**4.3 Interrelationships among the karstic areas (richness analysis and biological subterranean corridor)**

The five karstic areas involved, show a differences in the species composition and their numbers, in some places only one specimens are located, whilst another there are hundred or even miles (**Table 3**). However, in the first view or richness the Yucatan Peninsula is more diversity in the crustaceans but have two different habitats and in the freshwater the *Creaseria morleyi* and *Creaseriella anops* are too cosmopolitan; whilst in the coastal areas the anchialine habitats allow that species

d. Petén Region (**Figure 4**)

e. Chiquibul Region (**Figure 5**)

it confirmed only this last species.

Cenote Chempita.

**48**

was confirmed by fieldwork from authors.

*Natural History and Ecology of Mexico and Central America*

This area is part of the Yucatan Peninsula base, where the elevations are less evident, from 350 to 50 masl, and the drainage to underground by karstic soil of water is more representative, here the caves are on floor level, and local people as water source use them. In this area the principal species are freshwater prawns *Macrobrachium* and crabs from Pseudothelphusidae family. They are not showed cave life adaptations. In this region all animals

In Belize, there are several areas with karstic composition in the soil but only around of Mountains Systems has been recorded caves with long formations. Is important mentioned that close to Mexican border the soils is too similar to rest of Yucatan Peninsula and the potential to found caves or even cenotes is high. However, the caves recorded in Belize are mainly in Chiquibul region among 150 to 800 msal and in Islands and Cays where has been recorded

*Macrobrachium catonium*,*Typhopseudothelphusa acanthochela* and fishes from *Rhamdia laticauda*, however there are in description two new species of *Macrobrachium* species and one crab from the same family. In the anchialine systems has been reported *Xibalbanus cockei.* Jill Yager author that described

The geological history of this region has two main sections in first instance the Mountain Systems Development in the different geological times was producing a new subterranean habitats to some freshwater groups invaded these sites with a consequently a new opportunity to speciation but they could be seen as a biological subterranean corridor, because these species have the same selection pressures and the changes among them are so closed. However, as has been reported each cave is a new chance to produce some changes in the adaptation as outcome of isolation procedure that considering this the different species of freshwater prawns, crayfish, or crabs, in these places in average the oxygen are lower between 2 to 3 mg/l with a saturation of 60%; at same time the pH is around the neutral values with some peaks to alkalinity, normally all with freshwater conditions and values of temperature around the 18 to 22°C, in all these places the measures were taken with low depth. However, the Yucatan Peninsula have a different origin and the different ways to colonised this subterranean habitats, our results show that in the enormous plate the species are cosmopolitan but exclusively in they are as *Creaseria morleyi, Typhlatya mitchelli*. Another big faunistic group is from anchialine group that their marine habitats conditions there are species so very primitive as Remipedia with at less three species around the coastal caves, or different decapod species that has been reported with different origins, as *Procaris mexicana, Anchialocaris paulini*, *Agostocaris bozanici, A. zabaletai,Typhlatya dzilamensis, Barbouria cubensis*, or even *Calliasmata nohochi* and *Yagerocaris cozumel*. In this places where the anchialine habitats are present the salinity is closed to marine conditions 36 ups, with pH values clearly to alkalinity between 8 and 9, the oxygen dissolved are close to hypoxic conditions 0.15 to 0.3 mg/l, with 5 or 10% of saturation. The temperature is around the 24°C [28] an example of these behaviour is showed in the **Figure 6** to

anchialine systems. In there some crustaceans could be found as

**4.2 Ecological conditions to freshwater and anchialine habitats**

freshwater shrimp and crabs. However according with the geological development from all these regions and this report of species distribution the subterranean corridor existed in this case among Tehuantepec Itsthmus and Chiapas, Alta Verapaz and Chiquibul region for *Macrobrachium* genus, because the all these regions this genus inhabiting the different cave options producing several species

**Specimens recorded**

Yucatan Peninsula 24 4500 >5000 180 24 25.193 Alta Verapaz 4 18 >1000 4.5 4.5 4.5 Peten 2 5 >500 2.5 2 2 Chiquibul 6 16 >500 2.6 6 6.3

*Tropical Subterranean Ecosystems in Mexico, Guatemala and Belize: A Review of Aquatic…*

**Richness (Cave/sp)**

16 150 60–90 9.3 16 18.336

**Chao's S1**

**Burham & Overton S2**

Pseudothelphusidae crab family, and of course fishes species. Currently this corridor is not working to gene flow because the caves working like a barrier among populations and the distance are very significative which not happened in the Yucatan Peninsula where the existence of subterranean rivers has been reported.

(Mexico, Guatemala & Belize) is higher in comparison with those temperate zones in Mexico even, because how has been described previously there are more taxa (**Figures 7** and **8**) [10, 21, 22, 29]. Although as well had been described, in other continents are described with more detail the taxa numbers by example Europe where the main factor to produce these numbers are the efforts occupied in exploring and registered these taxa [30]. Therefore, the diversity comparison among these regions are too difficult, because depends in first instance of the correct reports and the effort to exploring the areas, all these data are an approximately about that the current status of biodiversity [31], showed the status among this subterranean diversity in the tropics using some cave as examples but is not determinant but in the aquatic habitats the crustaceans are reported as main taxa. However, is evident that the freshwater groups colonised in first instance those habitats close the mountains in this biological subterranean corridor, there are another group that cluster the Yucatan Peninsula Region and due the different origin from the Mountain Systems allow that these species are cosmopolitan distribution [6]. Finally the anchialine species group are totally different and their relationships are more closely with Antilles fauna [32–35]. Even among the regions there are important differences in the diversity not only in the composition of genus or families, too in the number of species and in the specimens registered, by example due that the regions are big land extension is few possible that only one or two specimens were registered, is we check the numbers of index as Chao's or Burman & Overton the diversity estimated increase few because the taxa included in the analysis had a good representation in the area, someone are cosmopolitans in the

that have phylogenetics relationships, at the same situations occurs with

The tropical subterranean aquatic biodiversity in Central America

**5. Discussion**

**Karstic Regions Species**

*DOI: http://dx.doi.org/10.5772/intechopen.97694*

*Comparison of richness among karstic regions.*

Tehuantepec Isthmus & Chiapas

**Table 3.**

**number**

**Cave number**

same region.

**51**

**Figure 6.**

*Profile of Anchialine deep ecosystems. A) Temperature-Salinity, B) pH-Salinity; C) Oxygen Dissolved-Salinity; D) Oxygen concentration-Salinity. The cenote Chemita located in Cozumel Island, have a representative of three water layers i) freshwater 0-16 m; brackish water 16–24m, and marine water 24–60 m.*

with more relationships with another Caribbean Islands species live, and normally these species have a microdistribution and marine origin recent. Is evident that this region the species that inhabiting, not share with another region.

In contrast in the Isthmus and Chiapas region the crustaceans have a freshwater origin and their microdistribution are mainly in the locality type for several


*Tropical Subterranean Ecosystems in Mexico, Guatemala and Belize: A Review of Aquatic… DOI: http://dx.doi.org/10.5772/intechopen.97694*

#### **Table 3.**

*Comparison of richness among karstic regions.*

freshwater shrimp and crabs. However according with the geological development from all these regions and this report of species distribution the subterranean corridor existed in this case among Tehuantepec Itsthmus and Chiapas, Alta Verapaz and Chiquibul region for *Macrobrachium* genus, because the all these regions this genus inhabiting the different cave options producing several species that have phylogenetics relationships, at the same situations occurs with Pseudothelphusidae crab family, and of course fishes species. Currently this corridor is not working to gene flow because the caves working like a barrier among populations and the distance are very significative which not happened in the Yucatan Peninsula where the existence of subterranean rivers has been reported.
