Section 1 Biology and Ecology

Chapter 1

Abstract

Ostracoda

3

1. Introduction

Crustacean

Imad Mahmood Ghafor

Crustaceans include all the animals of the phylum Arthropoda Crustacea; the word comes from the Latin crusta, which means shell. Crustaceans are a very diverse group of invertebrate animals which includes active animals such as the crabs, lobsters, shrimp, krill, copepods, amphipods, and more sessile creatures like barnacles. Arthropoda is the largest phylum of Animal Kingdom. It includes about 11,340,000 species in all habitats. This constitutes about 83% of all the known animal species on earth. Arthropoda includes spider, scorpions, prawns, crabs, millipedes, centipedes, and many other insects. Arthropoda is characterized by heteronomous metamerism, chitinous exoskeleton, and joined appendages. The evolutionary acquisition of these traits is known as arthropodization. In very small crustaceans, exchange of the respiratory gases occurs through the general body surface. Large aquatic arthropods respire through gills and book gills, whereas

terrestrial forms respire through trachea and book lungs.

Keywords: Arthropoda, exoskeleton, crustacean: burrow, sedimentology,

Crustaceans are cladocerans if they have 4–6 pairs of (thoracic) legs, lack any paired eyes, swim with their second pair of antennae, and have at least the head not covered by a carapace [1]. Crustaceans are some of the most important marine life to humans crabs, lobsters, and shrimp are widely fished and consumed around the world.

There are more than 52,000 species of crustaceans in the world, which include popular marine animals like lobsters, crabs, shrimp, crayfish, and barnacles. Smaller crustaceans breathe through their bodies and larger ones breathe through gills. Most crustaceans are dioecious, meaning individuals are male or female. Reproduction varies among species. Most of them are the most important marine animals.

Humans rely heavily on crustaceans for food; and crustaceans are also an important prey source for marine life in the ocean food chain for a variety of animals, including whales, fish, and pinnipeds; more diverse than any group of arthropods, crustaceans are second or third in abundance of all categories of animal life after insects and vertebrates. They live in inland and ocean waters from the Arctic to the Antarctic as well as from elevations in the Himalayas up to 16,000 feet to well below the sea level. All crustaceans have a hard exoskeleton which protects the animal from predators and prevents water loss. However, exoskeletons do not grow as the animal inside them grows, so crustaceans are forced to molt as they grow larger. The molting process takes between a few minutes to several hours. During molting, a soft exoskeleton forms underneath the old one and the old exoskeleton is shed. Since the new exoskeleton is soft, this is a vulnerable time for the crustacean until

#### Chapter 1

## Crustacean

Imad Mahmood Ghafor

#### Abstract

Crustaceans include all the animals of the phylum Arthropoda Crustacea; the word comes from the Latin crusta, which means shell. Crustaceans are a very diverse group of invertebrate animals which includes active animals such as the crabs, lobsters, shrimp, krill, copepods, amphipods, and more sessile creatures like barnacles. Arthropoda is the largest phylum of Animal Kingdom. It includes about 11,340,000 species in all habitats. This constitutes about 83% of all the known animal species on earth. Arthropoda includes spider, scorpions, prawns, crabs, millipedes, centipedes, and many other insects. Arthropoda is characterized by heteronomous metamerism, chitinous exoskeleton, and joined appendages. The evolutionary acquisition of these traits is known as arthropodization. In very small crustaceans, exchange of the respiratory gases occurs through the general body surface. Large aquatic arthropods respire through gills and book gills, whereas terrestrial forms respire through trachea and book lungs.

Keywords: Arthropoda, exoskeleton, crustacean: burrow, sedimentology, Ostracoda

#### 1. Introduction

Crustaceans are cladocerans if they have 4–6 pairs of (thoracic) legs, lack any paired eyes, swim with their second pair of antennae, and have at least the head not covered by a carapace [1]. Crustaceans are some of the most important marine life to humans crabs, lobsters, and shrimp are widely fished and consumed around the world.

There are more than 52,000 species of crustaceans in the world, which include popular marine animals like lobsters, crabs, shrimp, crayfish, and barnacles. Smaller crustaceans breathe through their bodies and larger ones breathe through gills. Most crustaceans are dioecious, meaning individuals are male or female. Reproduction varies among species. Most of them are the most important marine animals. Humans rely heavily on crustaceans for food; and crustaceans are also an important prey source for marine life in the ocean food chain for a variety of animals, including whales, fish, and pinnipeds; more diverse than any group of arthropods, crustaceans are second or third in abundance of all categories of animal life after insects and vertebrates. They live in inland and ocean waters from the Arctic to the Antarctic as well as from elevations in the Himalayas up to 16,000 feet to well below the sea level. All crustaceans have a hard exoskeleton which protects the animal from predators and prevents water loss. However, exoskeletons do not grow as the animal inside them grows, so crustaceans are forced to molt as they grow larger. The molting process takes between a few minutes to several hours. During molting, a soft exoskeleton forms underneath the old one and the old exoskeleton is shed. Since the new exoskeleton is soft, this is a vulnerable time for the crustacean until

the new exoskeleton hardens. After molting, crustaceans typically expand their bodies almost immediately, increasing by 40–80%. Most crustaceans reproduce sexually with a separate male and female.

#### 2. General characters of phylum Arthropoda

Arthropoda have the following description [2]:


10.Three parts (head, thorax, and abdomen).


#### 3. Classification of phylum Arthropoda

Phylum Arthropoda have different views concerning their phylogeny. So there is no absolute system of classification for this phylum. The below given classification is the most accepted one. Arthropoda classified into subphylums and classes three subphyla namely Trilobita, Chelicerata, and Mandibulata are definitively arthropods, classes Trilobita, Xiphosura, Arachinida, Crustacea, Cheliopoda, Diplopoda, and Hexapoda [3] (Table 1).

#### 4. Classification of the crustaceans

Crustaceans have been known to humans since ancient times and have provided us with sources of both food and legend. The classification of crustaceans has been quite variable; the system used by [4] presented an overview of crustacean classification, and readers are referred to that publication for a window into the labyrinthine history of this subphylum. This classification was recognized in [5, 6] (Table 2).

5. General characters of class Crustacea (Crusta = shell)

(Figure 2).

Classification of the Crustacea [25].

Table 2.

5

Phylum Arthropoda Subphylum Trilobata

DOI: http://dx.doi.org/10.5772/intechopen.89730

Classification of phylum Arthropoda.

Table 1.

Crustacean

Ex. Trithurus

Class Xiphosura

Chelicerata Mandibulata

— Diplopoda

— Hexapoda

Crustacea Ex. Palaemon

Cheliopoda Ex. Scolopendra

Ex. Spirobolus

Ex. Musca

Ex. Limulus

Arachinida Ex. Palamnaeous

1.Class Crustacea head, or cephalon (plus the acron), thorax and abjedium

#### Crustacean DOI: http://dx.doi.org/10.5772/intechopen.89730


#### Table 1.

the new exoskeleton hardens. After molting, crustaceans typically expand their bodies almost immediately, increasing by 40–80%. Most crustaceans reproduce

1.Cosmopolitan in distribution is found in aquatic, terrestrial, and aerial forms.

12.Growth type is by molting which sheds old skeleton and secretes a large one.

Phylum Arthropoda have different views concerning their phylogeny. So there is no absolute system of classification for this phylum. The below given classification is the most accepted one. Arthropoda classified into subphylums and classes three subphyla namely Trilobita, Chelicerata, and Mandibulata are definitively arthropods, classes Trilobita, Xiphosura, Arachinida, Crustacea, Cheliopoda, Diplopoda,

Crustaceans have been known to humans since ancient times and have provided us with sources of both food and legend. The classification of crustaceans has been quite variable; the system used by [4] presented an overview of crustacean classification, and readers are referred to that publication for a window into the labyrinthine history of this subphylum. This classification was recognized in [5, 6]

sexually with a separate male and female.

Crustacea

2. General characters of phylum Arthropoda

Arthropoda have the following description [2]:

2.Body has jointed appendages or legs.

5.Organ system level of organization.

6.Body is divisible into head, thorax and abdomen.

10.Three parts (head, thorax, and abdomen).

11.Exoskeleton composed of chitineous materials.

13.They are either oviparous or ovoviviparous.

3. Classification of phylum Arthropoda

3.Body is triploblastic.

7.Segmented.

8. Jointed appendages.

and Hexapoda [3] (Table 1).

(Table 2).

4

4. Classification of the crustaceans

9.Hard external skeleton.

4.Bilaterally symmetrical.

Classification of phylum Arthropoda.

## 5. General characters of class Crustacea (Crusta = shell)

1.Class Crustacea head, or cephalon (plus the acron), thorax and abjedium (Figure 2).

2.They are found in marine, fresh water and terrestrial habitats.

8. Life cycle

Crustacean

has developed [11].

involved.

to feed.

8.2 Eggs

it was an entirely separate species.

DOI: http://dx.doi.org/10.5772/intechopen.89730

of mating and reproducing [12].

crustaceans, such as the Marmorkrebs crayfish [13].

8.1 Mating system

[14] (Figures 1 and 2).

8.3 Larvae

7

The life cycle for different crustaceans may be different or they are

between one crustacean and the next when it comes to their life cycles.

similarities between one crustacean and the next when it comes to their lifecycles. The Crustacean class is the largest group of arthropods of a marine nature, and there are approximately 30,000 different species in this group alone. The life cycle for different crustaceans is going to have unique qualities, but there are also similarities

Nauplius stage—this stage of crustacean life cycle is perceived as being a defining link among all crustaceans. This is the first larval stage of crustaceans and consists only of crustacean head and telson as neither the abdomen nor the thorax

Zoea larval stage—the crustacean life cycle involves a larval stage that is known as a zoea. When the zoea name was given to the crustacean, naturalists believed that

Mysis or megalopa stage—the stage of growth following the zoea stage of growth

The crustacean is going will being to look more like to its adult form. This is also the stage of growth where the crustacean will depend more on foraging and grazing

Adult growth stage—the adult growth stage is reached by 1 year of age for the most crustacean. After a year has passed, most crustacean varieties will be capable

Crustacean produced by sexually: a small number is hermaphrodites, including Barnacles, Remipedes, and Cephalocarida. Some may even change sex during the course of their life. Parthenogenesis is also widespread among crustaceans, where viable eggs are produced by a female without needing fertilization by a male. This occurs in many branchiopods, some ostracods, some isopods, and certain "higher"

The fertilized eggs are simply released into the water column, while others have developed a number of mechanisms for holding on to the eggs until they are ready to hatch. Most decapods carry the eggs attached to the pleopods, while peracarids, notostracans, anostracans, and many isopods form a brood pouch from the carapace and thoracic limbs. Female Branchiura do not carry eggs in external ovisacs but attach them in rows to rocks and other objects. Most leptostracans and krill carry the eggs between their thoracic limbs; some copepods carry their eggs in special thin-walled sacs, while others have them attached together in long, tangled strings

The visual systems of crustacean larvae concentrate on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects of their vision. Larval compound eyes of these macrurans are all built on fundamentally the same optical plan, the transparent apposition eye, which is eminently suitable for modification into the abundantly diverse optical systems of the adults. Many of these

is either the Mysis or megalopa stage development on what crustacean group is


#### 6. Origin and application and crustacean

Crustaceans have important economic, ecological, and esthetic values and also can be appreciated from the perspective of bi-level functionality. Some larger crustaceans, including shrimp, lobsters, and crabs, are a major food commodity, while smaller crustaceans in their own way are integral to many food webs, sometimes considered a class or superclass rather than a subphylum. The scientific study of crustaceans is known as carcinology. Other names for carcinology are malacostracology, crustaceology, and crustalogy, and a scientist who works in carcinology is a carcinologist, crustaceologist, or crustalogist. The origin crustacean differs according to the order, suborder, or other taxons of the crustacean [7]. The earliest crustaceans are known from Cambrian sediments including the well-known Burgess Shale fauna. These primitive crustaceans are essentially worm-like in shape, but they do have many of the key features of crustaceans visible even on modern types such as shrimps [8]. So, the origin is based on the age of the genera and species. The small planktonic and free-swilling crustaceans were common in the Paleozoic era. It is relatively rare to find their skeletons entirely except in those places, like the Burgess Shale, where some catastrophic events smothered them quickly enough trevent their decay [9]. The crustaceans colonized mud firm grounds, which were formed by erosion during a rapid sea-level fall; thus, the burrows occur in direct association with erosional regressive surfaces and therefore are good stratigraphic indicators of abrupt paleoenvironmental change.

#### 7. Ecology

The ecology of the crustacean differs from one type to another. They live in aquatic and terrestrial environments, and all are marine but a few groups have adapted to life on land, such as terrestrial crabs and terrestrial hermit crabs. They are also found as burrowed in the sand of beaches will near access of water. Some freshwater crustaceans are crawfish and fairy shrimp. Crawfish live in lakes and rivers hidden under rocks and sand. Fairy shrimp are found in vernal ponds which are temporary puddles made by rain water. Various species have occupied almost every conceivable niche within the aquatic environment. An enormous abundance of free-swimming (planktonic) species occupies the open waters of lakes and oceans. Other species live at the bottom of the sea, where they may crawl over the sediment or burrow into it. Different species are found in rocky, sandy, and muddy areas. Some species are so small that they live in the spaces between sand grains. Others tunnel in the fronds of seaweeds or into man-made wooden structures. Some members of the orders Isopoda and Amphipoda extend down to the greatest depths in the sea and have been found in oceanic trenches at depths of up to 10,000 m. Crustaceans colonize lakes and rivers throughout the world, even high mountain lakes at altitudes of 5000 m. They range widely in latitude as well: in the high Arctic, some crustaceans use the short summer to develop quickly through a generation, leaving dormant stages to overwinter [10].

#### 8. Life cycle

2.They are found in marine, fresh water and terrestrial habitats.

4.Crustaceans have two pairs of antennae and two pair of maxillae.

crustaceans is known as carcinology. Other names for carcinology are

are good stratigraphic indicators of abrupt paleoenvironmental change.

ation, leaving dormant stages to overwinter [10].

The ecology of the crustacean differs from one type to another. They live in aquatic and terrestrial environments, and all are marine but a few groups have adapted to life on land, such as terrestrial crabs and terrestrial hermit crabs. They are also found as burrowed in the sand of beaches will near access of water. Some freshwater crustaceans are crawfish and fairy shrimp. Crawfish live in lakes and rivers hidden under rocks and sand. Fairy shrimp are found in vernal ponds which are temporary puddles made by rain water. Various species have occupied almost every conceivable niche within the aquatic environment. An enormous abundance of free-swimming (planktonic) species occupies the open waters of lakes and oceans. Other species live at the bottom of the sea, where they may crawl over the sediment or burrow into it. Different species are found in rocky, sandy, and muddy areas. Some species are so small that they live in the spaces between sand grains. Others tunnel in the fronds of seaweeds or into man-made wooden structures. Some members of the orders Isopoda and Amphipoda extend down to the greatest depths in the sea and have been found in oceanic trenches at depths of up to 10,000 m. Crustaceans colonize lakes and rivers throughout the world, even high mountain lakes at altitudes of 5000 m. They range widely in latitude as well: in the high Arctic, some crustaceans use the short summer to develop quickly through a gener-

malacostracology, crustaceology, and crustalogy, and a scientist who works in carcinology is a carcinologist, crustaceologist, or crustalogist. The origin crustacean differs according to the order, suborder, or other taxons of the crustacean [7]. The earliest crustaceans are known from Cambrian sediments including the well-known Burgess Shale fauna. These primitive crustaceans are essentially worm-like in shape, but they do have many of the key features of crustaceans visible even on modern types such as shrimps [8]. So, the origin is based on the age of the genera and species. The small planktonic and free-swilling crustaceans were common in the Paleozoic era. It is relatively rare to find their skeletons entirely except in those places, like the Burgess Shale, where some catastrophic events smothered them quickly enough trevent their decay [9]. The crustaceans colonized mud firm grounds, which were formed by erosion during a rapid sea-level fall; thus, the burrows occur in direct association with erosional regressive surfaces and therefore

Crustaceans have important economic, ecological, and esthetic values and also can be appreciated from the perspective of bi-level functionality. Some larger crustaceans, including shrimp, lobsters, and crabs, are a major food commodity, while smaller crustaceans in their own way are integral to many food webs, sometimes considered a class or superclass rather than a subphylum. The scientific study of

3.Possess jaw, like appendages called mandibles.

5.Some of appendages are biramous.

7. Ecology

Crustacea

6

6. Origin and application and crustacean

The life cycle for different crustaceans may be different or they are similarities between one crustacean and the next when it comes to their lifecycles. The Crustacean class is the largest group of arthropods of a marine nature, and there are approximately 30,000 different species in this group alone. The life cycle for different crustaceans is going to have unique qualities, but there are also similarities between one crustacean and the next when it comes to their life cycles.

Nauplius stage—this stage of crustacean life cycle is perceived as being a defining link among all crustaceans. This is the first larval stage of crustaceans and consists only of crustacean head and telson as neither the abdomen nor the thorax has developed [11].

Zoea larval stage—the crustacean life cycle involves a larval stage that is known as a zoea. When the zoea name was given to the crustacean, naturalists believed that it was an entirely separate species.

Mysis or megalopa stage—the stage of growth following the zoea stage of growth is either the Mysis or megalopa stage development on what crustacean group is involved.

The crustacean is going will being to look more like to its adult form. This is also the stage of growth where the crustacean will depend more on foraging and grazing to feed.

Adult growth stage—the adult growth stage is reached by 1 year of age for the most crustacean. After a year has passed, most crustacean varieties will be capable of mating and reproducing [12].

#### 8.1 Mating system

Crustacean produced by sexually: a small number is hermaphrodites, including Barnacles, Remipedes, and Cephalocarida. Some may even change sex during the course of their life. Parthenogenesis is also widespread among crustaceans, where viable eggs are produced by a female without needing fertilization by a male. This occurs in many branchiopods, some ostracods, some isopods, and certain "higher" crustaceans, such as the Marmorkrebs crayfish [13].

#### 8.2 Eggs

The fertilized eggs are simply released into the water column, while others have developed a number of mechanisms for holding on to the eggs until they are ready to hatch. Most decapods carry the eggs attached to the pleopods, while peracarids, notostracans, anostracans, and many isopods form a brood pouch from the carapace and thoracic limbs. Female Branchiura do not carry eggs in external ovisacs but attach them in rows to rocks and other objects. Most leptostracans and krill carry the eggs between their thoracic limbs; some copepods carry their eggs in special thin-walled sacs, while others have them attached together in long, tangled strings [14] (Figures 1 and 2).

#### 8.3 Larvae

The visual systems of crustacean larvae concentrate on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects of their vision. Larval compound eyes of these macrurans are all built on fundamentally the same optical plan, the transparent apposition eye, which is eminently suitable for modification into the abundantly diverse optical systems of the adults. Many of these

#### Crustacea

Interpretation of the crustacean burrows from Mallorca makes them very comparable to some modern and fossil thalassinidean burrow systems [17, 18], and it is a direct consequence of the versatile behavior of fossorial shrimps. The helical burrows described herein were very likely part of complex burrow systems produced by thalassinideans. From an ichnotaxonomic point of view, these would be

Helical burrows. (a) and (b) Different parallel-to-bedding sections showing their architectural variability.

Figure 4.

Figure 3.

Crustacean

DOI: http://dx.doi.org/10.5772/intechopen.89730

Figure 5. Cylindroleberididae.

9

Chthamalus stellatus (Sessilia).

Figure 1. Eggs of Potamon fluviatile, a freshwater crab.

Figure 2. Zoea larva of the European lobster, Homarus gammarus.

eyes contain a layer of reflective structures overlying the retina that produces a counter illuminating eye shine, so they are unique in being camouflaged both by their transparency and by their reflection of light spectrally similar to background light to conceal the opaque retina. Besides the pair of compound eyes, at least some crustacean larvae have a non-imaging photoreceptor system based on a naupliar eye and possibly other frontal eyes. Larval compound eye photoreceptors send axons to a large and well-developed optic lobe consisting of a series of neuropils that are similar to those of adult crustaceans and insects, implying sophisticated analysis of visual stimuli. The visual system fosters a number of advanced and flexible behaviors that permit crustacean larvae to survive extended periods in the plankton and allow them to reach acceptable adult habitats, within which to metamorphose [15].

#### 9. Crustacean burrow

Crustaceans are mainly males, excavate burrows largely in carbonate substrates, and are therefore referred to as the burrowing barnacles. While their greatest diversity is found in shallow tropical seas, the most generalized or primitive members are found for the most part in deep water (between 1000 and 3000 m). Trace fossils, ranging back to the Devonian if not the Ordovician [16], reveal that species once occupied relatively high latitudes in Northern Europe and Gondwanaland, and at least one extant species is known from Antarctic waters today.

#### Crustacean DOI: http://dx.doi.org/10.5772/intechopen.89730

Interpretation of the crustacean burrows from Mallorca makes them very comparable to some modern and fossil thalassinidean burrow systems [17, 18], and it is a direct consequence of the versatile behavior of fossorial shrimps. The helical burrows described herein were very likely part of complex burrow systems produced by thalassinideans. From an ichnotaxonomic point of view, these would be

Figure 3. Helical burrows. (a) and (b) Different parallel-to-bedding sections showing their architectural variability.

Figure 4. Chthamalus stellatus (Sessilia).

Figure 5. Cylindroleberididae.

eyes contain a layer of reflective structures overlying the retina that produces a counter illuminating eye shine, so they are unique in being camouflaged both by their transparency and by their reflection of light spectrally similar to background light to conceal the opaque retina. Besides the pair of compound eyes, at least some crustacean larvae have a non-imaging photoreceptor system based on a naupliar eye and possibly other frontal eyes. Larval compound eye photoreceptors send axons to a large and well-developed optic lobe consisting of a series of neuropils that are similar to those of adult crustaceans and insects, implying sophisticated analysis of visual stimuli. The visual system fosters a number of advanced and flexible behaviors that permit crustacean larvae to survive extended periods in the plankton and allow them to reach

Crustaceans are mainly males, excavate burrows largely in carbonate substrates, and are therefore referred to as the burrowing barnacles. While their greatest diversity is found in shallow tropical seas, the most generalized or primitive members are found for the most part in deep water (between 1000 and 3000 m). Trace fossils, ranging back to the Devonian if not the Ordovician [16], reveal that species once occupied relatively high latitudes in Northern Europe and Gondwana-

land, and at least one extant species is known from Antarctic waters today.

acceptable adult habitats, within which to metamorphose [15].

Zoea larva of the European lobster, Homarus gammarus.

Eggs of Potamon fluviatile, a freshwater crab.

9. Crustacean burrow

Figure 2.

8

Figure 1.

Crustacea

compound structures composed of pellet-lined (Ophiomorpha) and unlined (Thalassinoides) branching tunnels, sometimes with spreiten due to vertical shifting (Teichichnus), or double (Lapispira) helical elements. Such double helix elements (Lapispira) were previously known only from the Jurassic as isolated burrows, also assigned to crustaceans [13]. Despite the lesser geometric regularity of the Mallorcan burrows, the presence of a knobby lining and the fact that these may

Figure 6.

Fossil remains of a barnacle (Cirripedia—left) and a crab (Decapoda—right) found in the UCMP teaching collection (images by Karen Osborn). Fossil stomatopod, center (image by Dr. Cees Hof, used with permission).

be connected to branching systems. The new occurrence of this unusual ichnogenus may record a case of behavioral convergence expressed in burrow architecture [19] (Figures 3–6). While most crustaceans are marine, a large number of crayfish live in freshwater, including crayfish (Figure 7). Etyus martini is one of the more common crabs in the Gault Clay (Figure 8). Spiny lobsters are among the larger crustaceans. Big specimens can weigh several kilograms and make very good eating

The crustaceans, such as crabs and lobsters, that have hard exoskeletons reinforced with calcium carbonate tend to preserve well as fossils, but many crustaceans have only thin exoskeletons. Most of the crustacean fossils known are from coral reef or shallow sea-floor environments, but many crustaceans live in open seas, on deep sea floors, or in burrows. Crustaceans tend, therefore, to be rare in the fossil record than trilobites. Some crustaceans are reasonably common in Cretaceous and Cenozoic rocks, but barnacles have a particularly poor fossil record, with very few specimens from before the Mesozoic era. The Late Jurassic lithographic limestones of Solnhofen, Bavaria, which are famous as the home of Archaeopteryx, are relatively rich in decapod crustaceans (five pairs of legs), such as Eryon (an eryonoid), Aeger (a prawn), or Pseudastacus (a lobster). The "lobster bed" of the Greensand formation from the Cretaceous period, which occurs at Atherfield on the Isle of Wight, contains many well preserved examples of the small glypheoid lobster

Mecochirus magna. Crabs have been found at a number of sites, such as the

with a well-documented fossil record beginning in the early Ordovician (e.g., [20–24]). During the Ordovician period, ostracods already possessed a global

Ostracods are tiny crustaceans, typically about one to two millimeters in length,

Cretacoues Gault clay and the Eocene London clay.

11. Crustacean example: ostracods

(Figure 9).

11

Figure 9. Spiny lobsters.

Crustacean

DOI: http://dx.doi.org/10.5772/intechopen.89730

10. Geological history

Figure 7. Crayfish.

Figure 8. Etyus martini.

compound structures composed of pellet-lined (Ophiomorpha) and unlined (Thalassinoides) branching tunnels, sometimes with spreiten due to vertical shifting (Teichichnus), or double (Lapispira) helical elements. Such double helix elements (Lapispira) were previously known only from the Jurassic as isolated burrows, also assigned to crustaceans [13]. Despite the lesser geometric regularity of the Mallorcan burrows, the presence of a knobby lining and the fact that these may

Fossil remains of a barnacle (Cirripedia—left) and a crab (Decapoda—right) found in the UCMP teaching collection (images by Karen Osborn). Fossil stomatopod, center (image by Dr. Cees Hof, used with permission).

Figure 7. Crayfish.

Figure 6.

Crustacea

Figure 8. Etyus martini.

10

be connected to branching systems. The new occurrence of this unusual ichnogenus may record a case of behavioral convergence expressed in burrow architecture [19] (Figures 3–6). While most crustaceans are marine, a large number of crayfish live in freshwater, including crayfish (Figure 7). Etyus martini is one of the more common crabs in the Gault Clay (Figure 8). Spiny lobsters are among the larger crustaceans. Big specimens can weigh several kilograms and make very good eating (Figure 9).

#### 10. Geological history

The crustaceans, such as crabs and lobsters, that have hard exoskeletons reinforced with calcium carbonate tend to preserve well as fossils, but many crustaceans have only thin exoskeletons. Most of the crustacean fossils known are from coral reef or shallow sea-floor environments, but many crustaceans live in open seas, on deep sea floors, or in burrows. Crustaceans tend, therefore, to be rare in the fossil record than trilobites. Some crustaceans are reasonably common in Cretaceous and Cenozoic rocks, but barnacles have a particularly poor fossil record, with very few specimens from before the Mesozoic era. The Late Jurassic lithographic limestones of Solnhofen, Bavaria, which are famous as the home of Archaeopteryx, are relatively rich in decapod crustaceans (five pairs of legs), such as Eryon (an eryonoid), Aeger (a prawn), or Pseudastacus (a lobster). The "lobster bed" of the Greensand formation from the Cretaceous period, which occurs at Atherfield on the Isle of Wight, contains many well preserved examples of the small glypheoid lobster Mecochirus magna. Crabs have been found at a number of sites, such as the Cretacoues Gault clay and the Eocene London clay.

#### 11. Crustacean example: ostracods

Ostracods are tiny crustaceans, typically about one to two millimeters in length, with a well-documented fossil record beginning in the early Ordovician (e.g., [20–24]). During the Ordovician period, ostracods already possessed a global

biogeographical distribution from high southern latitudes to the palaeo-tropics [26]. Crustacean ostracods are variously represented in washing residue and thin sections, two valves (left and right valves), the two valves being joined together along the hinge line. The body covered by external shell called Carapace is composed of two valves connected in the Dorsal side. Two valves are equal in the genus Amphisites or overlapping in Cytherella. Ovoid shape or semi ovoid, 0.5–4 mmlength to about 30 mm. Articulation along the dorsal margin is further characterized by development of teeth, socket, ridges, and grooves all together called hinge element (hinge elements: teeth, socket, grooves, and ridge-bar). The body is subdivided into Cephalon, Thorax, and Posterior, seven pairs appendages (antenna, antennule, mandible, maxilla, 1st thoracic leg, 2nd thoracic leg, and 3rd thoracic leg), one eye center, and two lateral calcareous part—internal and outer lamella with the valves are hard calcareous part, Carapace—right and left valve connected with hinge (Figure 10).

11.1 Important part in the general shape of ostracods, on the external surface of

denticulations (resemble to tooth) accumulated on the external margin of the valves; the number and shape of these denticulation differ from one sp. to another sp. and these denticulation are more accumulated on the anteroventral

2.Caudal process: some of the species in Ostracoda are characterized by having elongated end that is long and narrow and ended by anus. This caudal process is on the mid-posterior or on the posterodorsal side or posteroventral side.

3.Hinge ears: some species of Ostracoda have protuberance on anterior side of

5.Eye tubercle: it is a protuberance on the anterior side which is the position of

Is shown in the carapace view. The outer surfaces of the ostracod valves can be smooth or ornamented with pits, striations, reticulations, spines, sulci, tubercles,

Important parts in Ostracoda. (a) Caudal process and alae structure (b) Side view showing right and left

the hinge line which is formed by addition of calcareous materials.

4.Posteroventral spine: it is an calcareous spine on the posteroventral side,

6.Anteroventral beak-rostrum (Cypridea): some genera of Ostracoda are characterized by having protuberance resembling to beak, which is most

1.Marginal denticulation: most of the species in Ostracoda have more

the test

Crustacean

eye.

11.2 Ornamentation

Figure 12.

13

and posteroventral of the test.

DOI: http://dx.doi.org/10.5772/intechopen.89730

usually to the posterior side.

abundant in the genus Cypridea.

and wing-shaped (alae) (Figure 11) [22].

valves (c) Merodont hinge and alae structure, reticulation.

Figure 10. Ostracoda shell.

Figure 11. Ornamentation in some species of Ostracoda.

biogeographical distribution from high southern latitudes to the palaeo-tropics [26]. Crustacean ostracods are variously represented in washing residue and thin sections, two valves (left and right valves), the two valves being joined together along the hinge line. The body covered by external shell called Carapace is composed of two valves connected in the Dorsal side. Two valves are equal in the genus Amphisites or overlapping in Cytherella. Ovoid shape or semi ovoid, 0.5–4 mmlength to about 30 mm. Articulation along the dorsal margin is further characterized by development of teeth, socket, ridges, and grooves all together called hinge element (hinge elements: teeth, socket, grooves, and ridge-bar). The body is subdivided into Cephalon, Thorax, and Posterior, seven pairs appendages (antenna, antennule, mandible, maxilla, 1st thoracic leg, 2nd thoracic leg, and 3rd thoracic leg), one eye center, and two lateral calcareous part—internal and outer lamella with the valves are hard calcareous

part, Carapace—right and left valve connected with hinge (Figure 10).

Figure 10. Ostracoda shell.

Crustacea

Figure 11.

12

Ornamentation in some species of Ostracoda.

#### 11.1 Important part in the general shape of ostracods, on the external surface of the test


#### 11.2 Ornamentation

Is shown in the carapace view. The outer surfaces of the ostracod valves can be smooth or ornamented with pits, striations, reticulations, spines, sulci, tubercles, and wing-shaped (alae) (Figure 11) [22].

#### Figure 12.

Important parts in Ostracoda. (a) Caudal process and alae structure (b) Side view showing right and left valves (c) Merodont hinge and alae structure, reticulation.

wall. Marginal pores: these pores penetrated the test wall vertically and are distributed on the external surface; the number of the pores differ from family, genus species, and important in classification. Marginal pore canal: long pores distributed on the marginal zone; more pores on the anterior part than the other parts are also important in the classification. Test in ostracods is composed of calcareous material with chitineous test around them which helps to fix the hinge. Hinge elements are

The teeth in crustacean differ from one taxon to another; for example, ostracods have Adont hinge which is the simplest, without teeth or sockets, and often form part of a contact groove on the larger valve and a corresponding ridge on the smaller valve. The Merodont hinge is composed of a tooth and socket at each end of a groove or ridge structure (complementary negative and positive structures in left and right valves). The Entomodont hinge differs from the merodont hinge style by having a coarsely crenulated anterior portion of the median groove/ridge element. The Amphidont hinge has a more complex median structure with an anterior tooth and socket (Figure 13).

Ostracods as a mode of life are pelagic (planktonic) by using organic-walled shell (less CaCO3) or by producing oil droplets. Pelagic ostracods are not preserved in the sediments, or benthic on/in the sea floor. They can burrow, swim near the sea-bed, or crawl on or through the sediment. Benthic forms occur in all the aquatic environments from the abyss to the shoreline. They also occur in estuaries, lagoons, freshwater lakes, ponds and streams, salt lakes, hot springs, and damp vegetation (Figure 14). Ostracods can be influenced ecologically by various factors such as [27]:

1.Type of the substrate: swimmers have smooth, thin, bean-shaped carapace; fine-grained (mud) dwellers have flattened ventral, wing-shaped carapace;

(Hinge elements: teeth, socket, grooves, ridge-bar) (Figure 12).

11.5 Distribution and ecology of ostracods

DOI: http://dx.doi.org/10.5772/intechopen.89730

11.4 Teeth

Crustacean

Figure 14.

15

Psychrospheric and thermospheric ostracods.

Figure 13. Teeth types in Ostracoda.

#### 11.3 Pores in ostracods

Normal pores (open normal pores and sieve normal pores) and open normal pores: these pores penetrated the carapace, but sieve normal pores penetrated the

#### Crustacean DOI: http://dx.doi.org/10.5772/intechopen.89730

wall. Marginal pores: these pores penetrated the test wall vertically and are distributed on the external surface; the number of the pores differ from family, genus species, and important in classification. Marginal pore canal: long pores distributed on the marginal zone; more pores on the anterior part than the other parts are also important in the classification. Test in ostracods is composed of calcareous material with chitineous test around them which helps to fix the hinge. Hinge elements are (Hinge elements: teeth, socket, grooves, ridge-bar) (Figure 12).

#### 11.4 Teeth

The teeth in crustacean differ from one taxon to another; for example, ostracods have Adont hinge which is the simplest, without teeth or sockets, and often form part of a contact groove on the larger valve and a corresponding ridge on the smaller valve. The Merodont hinge is composed of a tooth and socket at each end of a groove or ridge structure (complementary negative and positive structures in left and right valves). The Entomodont hinge differs from the merodont hinge style by having a coarsely crenulated anterior portion of the median groove/ridge element. The Amphidont hinge has a more complex median structure with an anterior tooth and socket (Figure 13).

#### 11.5 Distribution and ecology of ostracods

Ostracods as a mode of life are pelagic (planktonic) by using organic-walled shell (less CaCO3) or by producing oil droplets. Pelagic ostracods are not preserved in the sediments, or benthic on/in the sea floor. They can burrow, swim near the sea-bed, or crawl on or through the sediment. Benthic forms occur in all the aquatic environments from the abyss to the shoreline. They also occur in estuaries, lagoons, freshwater lakes, ponds and streams, salt lakes, hot springs, and damp vegetation (Figure 14).

Ostracods can be influenced ecologically by various factors such as [27]:

1.Type of the substrate: swimmers have smooth, thin, bean-shaped carapace; fine-grained (mud) dwellers have flattened ventral, wing-shaped carapace;

Figure 14. Psychrospheric and thermospheric ostracods.

11.3 Pores in ostracods

Teeth types in Ostracoda.

Figure 13.

Crustacea

14

Normal pores (open normal pores and sieve normal pores) and open normal pores: these pores penetrated the carapace, but sieve normal pores penetrated the

Ostracods are used for ecostratigraphy. Ecostratigraphy is the study of the occurrence and development of fossil communities throughout geologic time, as evidenced by biofacies, with particular reference to its relevance in stratigraphic correlation and other fields, such as biogeography and basin analysis. Ecostratigraphic studies by ostracods are based on their morphological changes and ornamentations,

which are divided into different biozones and as environmental zone based on, diversity, community, and species abundant, range of the species and

The genera Karsteneis karsteni and Cythereis longaeva shows that the ratio of closed valves that the ratio of closed valves (carapace) of high percent and thick in the center of the cretaceous basin (rapid rate of deposition) in bohemia than the other deposits along the sides which are thin sediment and of low rate of deposition. Example no. 1. Some ostracods in the Garagu Formation, Dhouck City, Kurdi-

Example no. 2. The biostratigraphic distribution of Late Ordovician ostracod faunas from the Ellis Bay Formation on western Anticosti Island are described. Some 62 species are recorded. The EllisBay Formation can be subdivided into three ostracod biozones (these being partial range zones) and an interregnum, in ascending stratigraphical order these being the Longiscula subcylindrica biozone, the Eurychilina erugoface biozone, the Tetradella anticostiensis biozone and an interregnum in the uppermost part of the succession, marked by the local extinction of several taxa at the terminus of the T. anticostiensis biozone. These intervals are only locally developed, and are not useful for inter-regional correlation. A small number of the Ellis Bay Formation ostracod species are recorded elsewhere, from Sandbian and Katian age successions. These include Aechmina richmondensis, Aechmina maccormicki, Baltonotella parsispinosa, Macrocyproides trentonensis, Microcheilinella

(a) Cytherella sp., (b) Neocythere cf. gottisi Damotte & Grosdidier, 1963, (c) Protocythere bedoulensis

Moullade 1966, (d) Rehacythereis bernardi, (e) Cypridea bispinosa (Jones 1878) [28].

environment.

Crustacean

11.7 Ostracods and sedimentology

DOI: http://dx.doi.org/10.5772/intechopen.89730

stan Region, North Iraq (Figure 16) [28].

lubrica and Spinigerites unicornis [29].

Figure 16.

17

Figure 15. The ecological distribution of recent Ostarcoda with some tropical represented, Brassier. 2004.

coarse-grained (sand) dwellers have thick carapace with coarse ornamentation; and interstitial ostracods are small, long, and robust.

2. Salinity: ostracods carapace morphology tends to vary according to variation in salinity. They occur in fresh water (0.0–0.5‰) of rivers and estuaries, brackish water (0.5–30‰) of lagoons and marshes, normal sea water (35– 45‰), and hypersaline water bodies (up to 57‰) of the closed seas, lakes, lagoons, and marginal bays.

Fresh water ostracods—simple morphology, hinge adont, thin carapace, no marginal pores, and other weakly developed variable abundance and diversity.

Most shelf seas ostracods: low abundance, high diversity, stenohaline Cytheropteron.

Brackish lagoon and estuaries ostracods: thick shell, weakly ornamented, marginal pore canal, amphidont hinge. High abundance, low diversity, euryhaline, Cyprideis with tubecles.

Hypersaline lagoons ostracods, high abundance, low diversity, euryhaline, Cyprideis. Marine ostracods-continental shelf: strongly calcified carapace, strongly ornamented, hinge well developed (Figure 15).

#### 11.6 Application

They occur in the sedimentary column since the early Ordovician; hence, they can be used as: stratigraphic markers, paleo-salinity indicators, paleo-depth indicators, biostratigraphy, biostratigraphic correlation, and in paleoecology.

They are used as:


#### Crustacean DOI: http://dx.doi.org/10.5772/intechopen.89730

Ostracods are used for ecostratigraphy. Ecostratigraphy is the study of the occurrence and development of fossil communities throughout geologic time, as evidenced by biofacies, with particular reference to its relevance in stratigraphic correlation and other fields, such as biogeography and basin analysis. Ecostratigraphic studies by ostracods are based on their morphological changes and ornamentations, which are divided into different biozones and as environmental zone based on, diversity, community, and species abundant, range of the species and environment.

#### 11.7 Ostracods and sedimentology

The genera Karsteneis karsteni and Cythereis longaeva shows that the ratio of closed valves that the ratio of closed valves (carapace) of high percent and thick in the center of the cretaceous basin (rapid rate of deposition) in bohemia than the other deposits along the sides which are thin sediment and of low rate of deposition.

Example no. 1. Some ostracods in the Garagu Formation, Dhouck City, Kurdistan Region, North Iraq (Figure 16) [28].

Example no. 2. The biostratigraphic distribution of Late Ordovician ostracod faunas from the Ellis Bay Formation on western Anticosti Island are described. Some 62 species are recorded. The EllisBay Formation can be subdivided into three ostracod biozones (these being partial range zones) and an interregnum, in ascending stratigraphical order these being the Longiscula subcylindrica biozone, the Eurychilina erugoface biozone, the Tetradella anticostiensis biozone and an interregnum in the uppermost part of the succession, marked by the local extinction of several taxa at the terminus of the T. anticostiensis biozone. These intervals are only locally developed, and are not useful for inter-regional correlation. A small number of the Ellis Bay Formation ostracod species are recorded elsewhere, from Sandbian and Katian age successions. These include Aechmina richmondensis, Aechmina maccormicki, Baltonotella parsispinosa, Macrocyproides trentonensis, Microcheilinella lubrica and Spinigerites unicornis [29].

#### Figure 16.

(a) Cytherella sp., (b) Neocythere cf. gottisi Damotte & Grosdidier, 1963, (c) Protocythere bedoulensis Moullade 1966, (d) Rehacythereis bernardi, (e) Cypridea bispinosa (Jones 1878) [28].

coarse-grained (sand) dwellers have thick carapace with coarse ornamentation; and interstitial ostracods are small, long, and robust.

The ecological distribution of recent Ostarcoda with some tropical represented, Brassier. 2004.

lagoons, and marginal bays.

ornamented, hinge well developed (Figure 15).

Cytheropteron.

Figure 15.

Crustacea

Cyprideis with tubecles.

They are used as:

present.

16

11.6 Application

2. Salinity: ostracods carapace morphology tends to vary according to variation in salinity. They occur in fresh water (0.0–0.5‰) of rivers and estuaries, brackish water (0.5–30‰) of lagoons and marshes, normal sea water (35– 45‰), and hypersaline water bodies (up to 57‰) of the closed seas, lakes,

Fresh water ostracods—simple morphology, hinge adont, thin carapace, no marginal pores, and other weakly developed variable abundance and diversity. Most shelf seas ostracods: low abundance, high diversity, stenohaline

Brackish lagoon and estuaries ostracods: thick shell, weakly ornamented, marginal pore canal, amphidont hinge. High abundance, low diversity, euryhaline,

Hypersaline lagoons ostracods, high abundance, low diversity, euryhaline, Cyprideis.

They occur in the sedimentary column since the early Ordovician; hence, they can be used as: stratigraphic markers, paleo-salinity indicators, paleo-depth indica-

1.Tools for biozonation of marine strata, as they occur from Cambrian to the

2. Indicators of ancient marine shorelines salinity, relative sea-floor depth.

Marine ostracods-continental shelf: strongly calcified carapace, strongly

tors, biostratigraphy, biostratigraphic correlation, and in paleoecology.

## 12. Conclusions

This chapter has the following conclusions:

Crustaceans (Arthropods) are a group of animals with an armored external skeleton (called an exoskeleton),

1.The hard exoskeleton is the part that is preserved as a fossil. Arthropod comes from the Greek words "arthro" meaning joint and "poda" meaning foot or leg.

References

Crustacean

91(1):255-273

2015;22:63-74

(3):379-397

County; 2001

1990;4:667

2012;9:349

19

[1] Ortega-Hernández J. Making sense of

DOI: http://dx.doi.org/10.5772/intechopen.89730

[9] Chen JY, Zhou GQ, Edgecombe GD, Ramsköld L. Head segmentation in early cambrian fuxianhuia: Implications for arthropod evolution. Science. 1995;

268(5215):1339-1343

[10] Emmett Duffy J, Thiel M. Evolutionary Ecology of Social and Sexual Systems: Crustaceans as Model

[11] Olesen J. Crustacean life cycles—

environmental adaptations. The Natural History of the Crustacea: Life Histories.

Organisms. Oxford; 2007

developmental strategies and

Oxford University Press; 2018

[12] Jennifer Uhl has been writing professionally since 2005. She writes primarily for the web and has been published as a ghostwriter in "Tropical Fish Magazine" and "Entrepreneur." She is pursuing a Bachelor of Science in health care from Mira Costa College

[13] Gurney R. Larvae of DECAPOD Crustacea (PDF). London: Ray Society;

[14] Mauchline J. Egg and brood sizes of

Laboratory. Scottish Marine Biological. Marine Ecology–Progress. 1988;43:251-

[15] Torres AP, Santos AD, Alemany F, Massutí E. Larval stages of crustacean species of interest for conservation and fishing exploitation in the western

Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews. 2003;62:1-103

[17] Dworschak PC, Rodrigues SA. A modern analogue for the trace fossil

oceanic pelagic crustaceans. Dunstaffnage Marine Research

Mediterranean. 2013

[16] Taylor PD, Wilson MA.

Gyrolithes: Burrows of the

1942. pp. 1-306

258

[2] Chandra PP. Assessment of plant diversity in homegardens of three ecological zones of Nepal. Ecoprint;

[3] Asvin P. Torres Ferran Palero Antonina Dos Santos Pere Abelló Edurne Blanco lexandra Boné and Guillermo Guerao: Larval stages of the deep-sea lobster Polycheles typhlops (Decapoda, Polychelida) identified by DNA analysis: Morphology, systematic, distribution and ecology. Helgoland Marine Research; September 2014;68

[4] Martin JW, Davis GE. An Updated Classification of the Recent Crustacea. Natural History Museum of Los Angeles

[5] Jose J, Pillai L. Taxonomy and identification of commerciall important crustacean of india. Indian Council of Agriculture Journal. 2013. 169 p

[6] Martin RF, Randriandraisana A, Boulvais P. Ampandrandava and similar

silicocarbonatitic melt of crustal origin. Journal of Afrivan Earthscience. 2014;2

[7] Emerson MJ, Schram FR. The origin of crustacean biramous appendages and the evolution of arthropoda. Science.

[8] Schram F, Vaupel K. Treatise On Zoology–Anatomy, Taxonomy, Biology the Crustacea Complementary to the Volumes Translated from the French of the Traité De Zoologie. Part B, Brill Leiden Boston: Koninklijke Brill NV;

phlogopite deposits in southern Madagascar: Derivation from a

'lower' and 'upper'stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848. Biological Reviews. 2016;


## Author details

Imad Mahmood Ghafor Department of Geology, College of Science, University of Sulaimani, Sulaimaniyah, Iraq

\*Address all correspondence to: imad.gafor@univsul.edu.iq

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## References

12. Conclusions

Crustacea

or leg.

This chapter has the following conclusions:

11,340,000 species in all habitats.

exoskeleton, and joined appendages.

skeleton (called an exoskeleton),

general body surface.

growth stage.

Author details

Iraq

18

Imad Mahmood Ghafor

Crustaceans (Arthropods) are a group of animals with an armored external

1.The hard exoskeleton is the part that is preserved as a fossil. Arthropod

2.Arthropoda is the largest phylum of Animal Kingdom. It includes about

3.Arthropoda is characterized by heteronomous metamerism, chitinous

5.Large aquatic arthropods respire through gills and book gills, whereas

terrestrial forms respire through trachea and book lungs.

9.Ostracoda is an important example in crustacean.

\*Address all correspondence to: imad.gafor@univsul.edu.iq

provided the original work is properly cited.

6.The earliest crustaceans are known from Cambrian sediments.

4. In very small crustaceans, exchange of the respiratory gases occurs through the

7.A majority of crustaceans habitats are aquatic and they live in either marine or freshwater environments, but a few groups have adapted to life on land, such as terrestrial crabs, terrestrial hermit crabs, and marine environments.

8.The life cycle for different crustaceans starts from the nauplius stage, followed by the zoea larval stage and post-larval stage, and finally ends with the adult

Department of Geology, College of Science, University of Sulaimani, Sulaimaniyah,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

comes from the Greek words "arthro" meaning joint and "poda" meaning foot

[1] Ortega-Hernández J. Making sense of 'lower' and 'upper'stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848. Biological Reviews. 2016; 91(1):255-273

[2] Chandra PP. Assessment of plant diversity in homegardens of three ecological zones of Nepal. Ecoprint; 2015;22:63-74

[3] Asvin P. Torres Ferran Palero Antonina Dos Santos Pere Abelló Edurne Blanco lexandra Boné and Guillermo Guerao: Larval stages of the deep-sea lobster Polycheles typhlops (Decapoda, Polychelida) identified by DNA analysis: Morphology, systematic, distribution and ecology. Helgoland Marine Research; September 2014;68 (3):379-397

[4] Martin JW, Davis GE. An Updated Classification of the Recent Crustacea. Natural History Museum of Los Angeles County; 2001

[5] Jose J, Pillai L. Taxonomy and identification of commerciall important crustacean of india. Indian Council of Agriculture Journal. 2013. 169 p

[6] Martin RF, Randriandraisana A, Boulvais P. Ampandrandava and similar phlogopite deposits in southern Madagascar: Derivation from a silicocarbonatitic melt of crustal origin. Journal of Afrivan Earthscience. 2014;2

[7] Emerson MJ, Schram FR. The origin of crustacean biramous appendages and the evolution of arthropoda. Science. 1990;4:667

[8] Schram F, Vaupel K. Treatise On Zoology–Anatomy, Taxonomy, Biology the Crustacea Complementary to the Volumes Translated from the French of the Traité De Zoologie. Part B, Brill Leiden Boston: Koninklijke Brill NV; 2012;9:349

[9] Chen JY, Zhou GQ, Edgecombe GD, Ramsköld L. Head segmentation in early cambrian fuxianhuia: Implications for arthropod evolution. Science. 1995; 268(5215):1339-1343

[10] Emmett Duffy J, Thiel M. Evolutionary Ecology of Social and Sexual Systems: Crustaceans as Model Organisms. Oxford; 2007

[11] Olesen J. Crustacean life cycles developmental strategies and environmental adaptations. The Natural History of the Crustacea: Life Histories. Oxford University Press; 2018

[12] Jennifer Uhl has been writing professionally since 2005. She writes primarily for the web and has been published as a ghostwriter in "Tropical Fish Magazine" and "Entrepreneur." She is pursuing a Bachelor of Science in health care from Mira Costa College

[13] Gurney R. Larvae of DECAPOD Crustacea (PDF). London: Ray Society; 1942. pp. 1-306

[14] Mauchline J. Egg and brood sizes of oceanic pelagic crustaceans. Dunstaffnage Marine Research Laboratory. Scottish Marine Biological. Marine Ecology–Progress. 1988;43:251- 258

[15] Torres AP, Santos AD, Alemany F, Massutí E. Larval stages of crustacean species of interest for conservation and fishing exploitation in the western Mediterranean. 2013

[16] Taylor PD, Wilson MA. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews. 2003;62:1-103

[17] Dworschak PC, Rodrigues SA. A modern analogue for the trace fossil Gyrolithes: Burrows of the

thalassinidean shrimp Axianassa australis. Lethaia. 1997;30(1):41-52

[18] Mayoral E, Mun F. Nuevosi datos icnotaxnomicos sobre Gyrolithes del Pliocene inferior de la Cuenca del Guadalquiver (Lepi, Huelva, Espana). Rivista Espanola de Paleontologia. 1998; 13:61-69

[19] Lanés S, Manceñido M, Damborenea S. Lapispira: A double helicoidal burrow from Jurassic marine nearshore environments. In: Bromley RG, Buatois LA, Mángano MG, Genise J, Melchor R, editors. Sediment-Organism Interactions: A Multifaceted Ichnology. Tulsa: SEPM; 2007. pp. 59-78

[20] Gibert A. Toleration, Diversity and Global Justics. University of Pennsylvania; 2003. 233 p

[21] Haq BU, Boersma AB. Introduction to Marine Micropaleontology. North Holland: Elsevier; 1978. 376 p

[22] Brassier MD. Microfossils. In: Blackwell Publling Publishing. 1980

[23] Tinn O, Meidla T. Phylogenetic relationships of early middle Ordovician ostracods of Baltoscandia. Palaeontology. 2004;47:199-221

[24] Williams M, Floyd JD, Salas MJ, Siveter DJ, Stone P, Vannier JMC. Patterns of ostracod migration for the "North Atlantic" region during the Ordovician. Palaeogeography, Palaeoclimatology, Palaeoecology. 2003; 195:193-228

[25] Siveter DJ, Vannier JM, Palmer D. Silurian Myodocopes: Pioneer pelagic ostracods and the chronology of an ecological shift. Journal of Micropalaeontology. UK: University of Leicester; 1991;10(2):151-173

[26] Bennett CE, Williams M, Leng MJ, Siveter DJ, Davies SJ, Sloane SH, et al. Diagensis of fossil ostracods:

Implications for stable isotope based palaeoenvironmental reconstruction. Palaeogeography, Palaeoclimatology, Palaeoecology. Cambridge University Press; 2011;305:150-161

[27] Benson RH. The origin of the psychrosphere as recorded in changes of deep-sea ostracode assemblages. Lethaia. Wiley Online; 1975;8(1):69-83

[28] Ghafor IM, Mohialdeen IMJ. Early cretaceous microfossils associations (foraminifera, ostracoda, calcareous algae, and coral) from the Garagu Formation, Duhok Area, Kurdistan Region, Northern Iraq. Arabian Journal of Geosciences. 2018;11(15):1-206

[29] Taha ZA. The taxonomic, biogeographical, palaeogeographical and palaeoecological significance of the late ordovician Ostracod fauna of the Ellis Bay Formation, Anticosti Island, Eastern Canada [Ph.D. thesis]. United kingdom: Department of Geology University of Leicester; 2018

**21**

**Chapter 2**

**Abstract**

surfaces.

**1. Introduction**

Nicobar is focused.

**2. Methods**

keys [3].

The Robber Crab *Birgus latro*

The robber or coconut crab *Birgus latro* (Linnaeus, 1767) is a terrestrial hermit crab. It is the largest—land living arthropod in the world. As far as India is concerned, distribution of this crab is restricted to Great Nicobar Island and South Sentinel Island in Andaman and Nicobar Archipelago. The crab divided into a front section (cephalothorax), which has eight legs, and an abdomen. The front-most pair of legs has large chelae (claws), with the left being larger than the right. The next two pairs, as with other hermit crabs, are large, powerful walking legs with pointed tips, which allow coconut crabs to climb vertical or overhanging

The robber or coconut crab (*Birgus latro*; Linnaeus, 1767) is a terrestrial hermit crab. It is the largest—land living arthropod in the world. As far as India is concerned, distribution of this crab is restricted to Great Nicobar Island and South Sentinel Island in Andaman and Nicobar Archipelago. In the Nicobar Islands the species has been reported from Car Nicobar [1], Little Nicobar, Katchal, Camorta and Great Nicobar [2]. The crab separated into a visible section (cephalothorax), which has eight legs, and an abdomen. The next two pairs, as with other hermit crabs, are large, powerful walking legs with pointy tips, which allow coconut crabs to climb vertical or overhanging surfaces. The fourth pair of legs is slighter with tweezer-like chelae at the end, allowing young coconut crabs to grip the inside of a shell or coconut husk to carry for protection; adults use this pair for walking and climbing. The last pair of legs is very small and is used by females to tend their eggs, and by the males in mating. In the present study, the general ecology of coconut crabs in around great

Coconut crabs are generally "easy to collect" and most often hand picking is very effective in intertidal zones, Crabs can be preserved wet in 6–10% formalin for further study. Field photographs by using the following taxonomic identification

(Linnaeus, 1767)

**Keywords:** *Birgus latro*, Nicobar, India, robber crab

*Selvaraj Kumaralingam*

#### **Chapter 2**

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