Tantilla wilcoxi
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publication ID |
https://doi.org/ 10.5281/zenodo.13237132 |
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persistent identifier |
https://treatment.plazi.org/id/E24187CD-FF91-FFC7-FCD9-EAC202F8C5D8 |
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treatment provided by |
Felipe |
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scientific name |
Tantilla wilcoxi |
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Examination of the above-listed species indicates that of the 65 single-region species in Coahuila, 22 are country endemics and nine are state endemics. The remaining 34 are non-endemic species that are also distributed in the USA.
Coefficient of Biogeographic Resemblance. A Coefficient of Biogeographic Resemblance (CBR) matrix was created for examining herpetofaunal relationships among the 10 physiographic regions of Coahuila ( Table 6) and these data were used to produce a UPGMA dendrogram ( Fig. 12 View Fig ). As mentioned above, the numbers of species within the 10 physiographic regions of Coahuila range from a high of 91 species within the Sierras y Llanuras Coahuilenses (SLC) to a low of 38 within Laguna de Mayrán (LDM) . The mean species richness number for all 10 regions is 50.3. The numbers of species shared between regions range from 20 to 45. The lowest value of 20 is found between only one pair of regions, the Llanuras de Coahuila y Nuevo León (LCN) and Gran Sierra Plegada (GSP) . The highest number is also shared between only one pair of regions, the SLC and Serranías del Burro (SDB). The mean number of shared species among the 45 regional pairings is 32.9. The lowest number of 20 shared species between LCN and GSP makes biogeographic sense because these two regions are situated at opposite ends of the state, are not connected geographically, and are environmentally quite different: LCN contains subhumid lowland plains and hills versus GSP with semihumid to subhumid highland mountainous areas carved by deep valleys. Also, GSP has a much smaller area in Coahuila than does LCN. On the other hand, the two regions with the highest number of 45 shared species are SLC and SDB. These two regions share part of their borders and both contain similar ecological regimes. Unlike the situation in Tamaulipas ( Terán-Juárez et al. 2016), the higher numbers of species in the regional pairings in Coahuila, with the exception of SLC (91 species), do not necessarily equate to higher numbers of shared species, which is more similar to the patterns shown in adjacent Nuevo León (Navárez-de los Reyes et al. 2016). This discrepancy is most likely due to the larger number of included physiographic regions, and the lower number of shared species from more distant regions. Reflecting this trend, the following pairwise comparisons of regions are aligned in order of highest to lowest species richness (underlined values) and their corresponding numbers of shared species (in parentheses) with all other regions; see text and map for discussions on characteristics and sizes of the regions:
SLC 91: SDB (45), SLP (40), PSP (44), STR (34), GSP (31), LCN (40), LDM (32), LSV (42), BDM (38).
LCN 53: GSP (20), STR (21), PSP (24), SLP (24), SDB (28), SLC (40), LDM (22), LSV (23), BDM (22).
GSP 51: LCN (20), STR (31), PSP (32), SLP (29), SDB (27), SLC (31), LDM (29), LSV (29), BDM (29).
PSP 49: STR (35), GSP (32), LCN (24), SLP (38), SDB (37), SLC (44), LDM (36), LSV (36), BDM (37).
STR 47: GSP (31), LCN (21), PSP (35), SLP (34), SDB (30), SLC (34), LDM (32), LSV (32), BDM (33).
SDB 45: SLP (35), PSP (27), STR (30), GSP (27), LCN (28); SLC (45), LDM (34), LSV (36), BDM (34).
BDM 45: LSV (38), LDM (37), SLC (38), SDB (34), SLP (36), PSP (37), STR (33), GSP (29), LCN (22).
LSV 44: BDM (38), LDM (37), SLC (42), SDB (36), SLP (37), PSP (36), STR (32), GSP (29), LCN (22).
SLP 40: BDM (36), LSV (37), LDM (36), SLC (40), SDB (35), PSP (38), STR (34), GSP (29), LCN (24).
LDM 38: BDM (37), SLP (36), PSP (36), STR (32), GSP (29), LCN (22), SLC (37), SDB (34), LSV (34).
SLC, with its 91 species, is the largest physiographic region in Coahuila that shares borders to variable extents with five of the nine other regions in the state (LCN, SDB, PSP, LSV, SLP), including the 2 nd and 4 th most speciose regions (LCN, PSP). The 91 species in SLC reveals a large discrepancy between it and all nine other regions in the state. Ninety-one species is 38 more than found in LCN, the second most species-rich region with 53 species, whereas the total difference for all nine of the other regions is only 15 species between the 53 species in LCN and the 38 species in LDM. LCN is a lowland region next to the Rio Grande with few montane landscapes, but it contains several generalist herpetofaunal species that also exist in adjacent montane regions of Coahuila at lower elevations. PSP is mostly separated from LCN by two other regions to its north (LDM, SLP); however, it shares a geographic connection through a northwestern extension of PSP in Nuevo León (Nevárez-de los Reyes et al. 2016).
The following data show ranges and mean numbers of shared species for each of the 10 regions listed above that are arranged according to increasing mean numbers (bold in parentheses) with underlined values referring to species richness in each region:
Llanuras de Coahuila y Nuevo León ( LCN) (53): 20– 40 (24.7)
Gran Sierra Plegada - GSP (51): 20–32 (28.5)
Sierras Transversales - STR (47): 21–35 (31.3) Laguna de Mayrán - LGM (38): 22–37 (33.3)
Bolsón de Mapimí - BDM (45): 22–38 (33.8) Serranías del Burro - SDB (45): 27–45 (34.0)
Llanuras y Sierras Volcánicas - LSV (44): 22–42 (34.3) Sierra de la Paila - SLP (40): 24–40 (34.3)
Pliegues de Saltillo Parras - PSP (49): 24–38 (35.4) Sierras y Llanuras Coahuilenses - SLC (91): 31–45 (39.0)
With the exception of SLC and PSP (1 st and 4 th highest in species richness, and 1 st and 2 nd highest mean numbers of shared species, respectively), the mean number of pairwise species comparisons between all other regions indicate that higher species richness in a region does not necessarily translate into a higher mean number of shared species when all regions are totaled. Apparent extreme examples of this are: LCN, GSP, and STR, respectively, having the 1 st, 2 nd, and 3 rd highest numbers of species and lowest mean numbers of shared species. It makes sense that LCN would share fewer species with other regions in Coahuila because of its ecological uniqueness associated with lower elevations and general differences in vegetation formations and topography, as well as herpetofaunal affinities to the United States northward across the Rio Grande. GSP has the smallest area of all regions in the state, but is much more extensive when considering it also exists in Nuevo León and Tamaulipas (Nevárez-de los Reyes et al. 2016; Terán-Juárez et al. 2016). STR is a slender montane region with high species richness positioned primarily within Coahuila across its entire southern border.
UPGMA Dendrogram. Based on the data in Table 6, a UPGMA dendrogram ( Fig. 12 View Fig ) was created to illustrate the herpetofaunal resemblance patterns in a hierarchical fashion among the 10 physiographic regions of Coahuila ( Fig. 1 View Fig ). The patterns are different when compared to those shown in the two other northern Mexico states bordering Texas that were covered in previous MCS publications: Nuevo León (Nevárez-de los Reyes et al. 2016) and Tamaulipas ( Terán-Juárez et al. 2016). The Coahuila dendrogram shows the similarity relationships in descending order from the most similar regions, SLP clustering with LDM at a value of 0.92, down to the lowest value, where LCN clusters with all the other regions at a value of 0.48. In other words, there are no distinct subgroupings within the dendrogram, which indicates on a biogeographic scale that there are no distinct subgroups composed of distributional units that share more closely related herpetofaunas. On the other hand, neighboring Nuevo León with seven regions has two distinct biogeographic subgroups, a southern unit containing two regions and a more northern unit containing five regions that clusters with the southern unit at the 0.37 similarity level. Tamaulipas, also with seven recognized regions, has the most complex pattern of herpetological similarity of these three states. Two biogeographic subgroups are found in what can be considered the northern and eastern sections of the state. One of those subgroups contains three regions that make up the majority of the state’s area, while the other subgroup is comprised of two small disjunct highland regions that cluster together at the 0.55 level; and both are nested within one of the other subgroup’s regions. Those two subgroups cluster with each other at the 0.46 similarity level. One of the two remaining regions, which make up the extreme southwestern sector of Tamaulipas, clusters independently with the other two biogeographic subgroups at the 0.44 level of herpetofaunal similarity. The last region, which is the southwestern-most section of the state, is the most distinctive of the seven, thereby clustering with the others at the 0.23 level of herpetological similarity.
In summary, the UPMGA dendrogram for Coahuila shows that the lowland non-montane region ( LCN) bordering the Rio Grande and Texas is the most distinctive region in Coahuila as far as herpetological similarity goes, based on numbers of shared species. It also shows a pattern of similarity among regions in close proximity to each other that also share ecological parameters either within the state or through areas of the same physiographic region outside Coahuila .
Distribution Status Categorizations
The discussion of the distribution status of Coahuilan herpetofauna members uses the system developed by Alvarado-Díaz et al. (2013), and employed in all the other entries in the Mexican Conservation Series. The categories in the system are non-endemic, country endemic, state endemic, and non-native ( Tables 7 and 8).
Given the 512-km-long border shared between Coahuila and Texas (http://wikipedia.org; accessed 11 August 2018), it is not surprising that the largest component of the herpetofauna falls into the non-endemic category. Of the 143 species comprising the Coahuilan herpetofauna, 100 species (69.9% of the total) belong to this category. Almost half (49) of the non-endemic species are snakes, and this number is only five fewer than the total number of snake species in the entire herpetofauna ( Table 8). The 76 non-endemic squamate species are 71.7% of the total of 106 species for the state. In addition, a large portion of the state’s anurans (17 of 20; 85.0%) are also non-endemic species. On the other hand, slightly more than half the turtle species (seven of 13; 53.8%) are non-endemic to Coahuila ( Table 8).
The next largest component is the 31 (21.7%) country endemic species, most of which are squamates, including 18 lizards and five snakes (74.2%). The remainder are amphibians (six species; 19.4%) and turtles (two species; 6.5%). Almost half of the country endemics are phrynosomatid lizards (14 of 31; 45.2%).
Only nine of the species (6.3%) in Coahuila are state endemics. Six of these are lizards ( Gerrhonotus lugoi , G. mccoyi , Crotaphytus antiquus , Sceloporus gadsdeni , Uma exsul , and Scincella kikaapoa ) and three are turtles ( Terrapene coahuila , Trachemys taylori , and Apalone atra ).
The number of non-native species in Coahuila is only three, the ranid frog Lithobates catesbeianus , the gekkonid lizard Hemidactylus turcicus , and the emydid turtle Trachemys scripta . These three species also were reported as introduced into Nuevo León (Nevárez-de los Reyes et al. 2016).
The number of endemic species in Coahuila (country and state endemics combined) is 40, which is 4.9% of the total number of endemic species for Mexico (811; Johnson unpub.). The number of non-endemic species is 100, which is 19.7% of the total of such species in the entirety of Mexico (508; Johnson unpub.).
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Lincoln City and County Museum |
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