Nototriton tomamorum, Townsend, Josiah H., Butler, Michael, Wilson, Larry David & Austin, James D., 2010
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publication ID |
https://doi.org/ 10.5281/zenodo.194769 |
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https://doi.org/10.5281/zenodo.5618714 |
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persistent identifier |
https://treatment.plazi.org/id/B61687D9-FFA4-E916-0186-F99FFAFBFD77 |
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Plazi |
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scientific name |
Nototriton tomamorum |
| status |
sp. nov. |
Nototriton tomamorum View in CoL new species
( Figs. 2 View FIGURE 2 , 3 View FIGURE 3 )
Holotype: A female (UF 155377) from 2.5 km NNE of La Fortuna (15°25.965’N, 87°18.556’W), 1550 m, Refugio de Vida Silvestre Texiguat, Departamento de Yoro, Honduras, collected 9 April 2008 by J. Slapcinsky and the field team of J. M. Butler, L. P. Ketzler, N. M. Stewart, J. H. Townsend, and L. D. Wilson. Original field number JHT 2437.
Diagnosis. A small member of the genus Nototriton (SVL= 26.9 mm; Table 2 View TABLE 2 ) based on having 13 costal grooves (>16 costal grooves in Oedipina ), hands and feet longer than broad (hands and feet broader than long in Bolitoglossa ), and nares that are smaller than most Cryptotriton and Dendrotriton ( Fig. 3 View FIGURE 3 A, B; 0.018 NL/ SVL; 0.020–0.029 NL/SVL in Cryptotriton [except some individuals of C. veraepacis ] and Dendrotriton ). Cryptotriton veraepacis has nares ranging from 0.017–0.027 NL/SVL (mean 0.022), and can be differentiated from N. tomamorum by having a uniformly dark gray ventral surface (ventral surface pale with gray flecks in N. tomamorum ; Fig. 2 View FIGURE 2 ). Generic placement in Nototriton is also strongly supported by sequence data from the mitochondrial genes 16S and cob (Table 3; Fig. 4 View FIGURE 4 ). This new species is distinguished from all other Nototriton , except N. richardi and N. tapanti , by having syndactylous hands and feet ( Fig. 3 View FIGURE 3 C, D; hands and feet with free, differentiated toes in all other species) and relatively large nares ( Fig. 3 View FIGURE 3 A, B; 0.018 NL/SVL versus 0.010–0.016 in N. picadoi , 0.003–0.014 in N. abscondens , 0.012 in N. stuarti , 0.005–0.011 in N. barbouri , 0.006–0.009 in N. lignicola , 0.004–0.009 in N. guanacaste , 0.004–0.005 in N. brodiei , 0.003 in N. limnospectator , 0.003 in N. major , and 0.002–0.003 in N. saslaya ). Nototriton tomamorum can be further differentiated from members of the N. barbouri group by having a broader head (0.145 HW/SVL versus 0.138 in N. stuarti , 0.104–0.132 in N. barbouri , 0.120 in N. brodiei , 0.103–0.118 in N. lignicola , and 0.095–0.118 in N. limnospectator ) and fewer maxillary teeth (26, versus 36 in N. stuarti , 41–54 in N. barbouri , 42–55 in N. limnospectator , 46–54 in N. lignicola , and 60–62 in N. brodiei ), from members of the N. picadoi group by having a relatively shorter tail (0.911 TL/SVL, versus 1.441 in N. major , 1.123–1.344 in N. picadoi , 1.013– 1.365 in N. abscondens , 1.210–1.337 in N. guanacaste , and 1.10–1.30 in N. gamezi ) and narrower feet (0.037 HFW/SVL, versus 0.058–0.071 in N. abscondens , 0.059 in N. major , 0.060–0.070 in N. picadoi , and 0.066– 0.072 in N. guanacaste ), and from N. saslaya by having shorter forelimbs (0.160 FLL/SVL, versus 0.194– 0.210 in N. saslaya ) and hind limbs (0.197 HLL/SVL, versus 0.217–0.244 in N. saslaya ) and narrower feet (0.037 HFW/SVL, versus 0.075–0.091 in N. saslaya ). The new species also differs from N. richardi and N. tapanti in having a pale ventral surface mottled with gray chromatophores (ventral surface brown with dark flecks in N. richardi and dark brown in N. tapanti ), by having a tail that is shorter than the snout-vent length (0.91 TL/SVL, versus 1.072–1.482 in N. richardi and 1.205 in N. tapanti ), longer forelimbs (0.160 FLL/SVL, versus 0.140–0.146 in N. richardi and 0.147 in N. tapanti ), longer hind limbs (0.197 HLL/SVL, versus 0.174– 0.187 in N. richardi and 0.174 in N. tapanti ), and narrower feet (0.037 HFW/SVL, versus 0.044–0.050 in N.
richardi and 0.041 in N. tapanti ). This new species is also well differentiated from all other species of Nototriton based on mitochondrial sequence data (Table 3), and is 3.6–6.0% divergent on 16S and 10.2– 15.1% divergent on cob from all other congeners.
Description of holotype. Nototriton tomamorum is known only from a single, presumably female (mental gland and cloacal papillae absent) specimen, preserved with its mouth open and tongue extended, and is a relatively small member of the genus (SVL= 26.9 mm, total length= 51.4 mm) with a slender body and reduced limbs. Its head is rounded and slightly broader than the body, and the nostrils are relatively large (NL/ SVL=0.018), and the snout is rounded and of moderate length ( Fig. 3 View FIGURE 3 A, B). The nasolabial protuberances are apparent but not well developed, and barely extend below the upper lip line. The eyes are relatively large and protuberant, and the parotoid glands appear large but not well defined. The teeth are exceedingly small; there are approximately 26 maxillaries, 4 premaxillaries set slightly forward from the maxillary teeth, and 11 vomerines; vomerine teeth are arranged in two short medially-positioned arches. The limbs are short (CLL/ SVL=0.36), with the adpressed limbs being separated by approximately 5.5 costal grooves. The hands and feet are narrow and have poorly-developed, poorly-differentiated digits that are fused and lack subdigital pads ( Fig. 3 View FIGURE 3 C, D). The free tips of digits III on the hands and III and IV on the feet are pointed, and digits I, II and IV on the hands and I, II, and V on the feet are very short and essentially completely fused, being demarcated by shallow grooves on the dorsal side of the feet. The relative length of the digits is I<IV<II<III on the hands and V<I<II<IV<III on the feet. The tail is slightly shorter than the body (TL/SVL=0.91), with a slight basal constriction most apparent on the ventral side, and is slightly compressed laterally (tail depth 1.17 times tail width at level of basal constriction).
Measurements of holotype (in mm). SVL 26.9; AG 15.2; TW 3.6; HL 4.8; HW 3.9; TL 24.5; HLL 5.3; FLL 4.3; CLL 9.6; HFL 1.7; HFW 1.2; NL 0.5; eye length 1.6; eye width 1.2; interorbital distance 1.4; anterior rim of orbit to snout 1.1; distance separating internal nares 0.8; distance separating external nares 1.8; snout projection beyond mandible 0.6; tip of snout to axilla 7.7; distance from axilla to groin 15.2; snout to anterior edge of vent 24.9; tail depth at basal constriction 2.8; tail width at basal constriction 2.4.
Coloration of holotype. Dorsal surfaces of head, body, and tail medium grayish brown, with profuse pale chromatophores laterally, becoming less abundant dorsolaterally. The head has some pale mottling on the top of the snout, and two irregular lines of pale chromatophores extending from the lateral region above the forelimbs onto the posterior portion of the head and parotoid glands. There is a very thin, pale middorsal stripe, with a herringbone pattern with lines extending from the middorsal stripe posteriorly. There is an indistinct dark dorsolateral stripe starting about one-third the way down the trunk and extending onto the proximal one-third of the tail. Ventral surface of head, body, and tail cream, mottled with dark gray chromatophores, becoming somewhat more profuse toward the distal end of the tail.
Etymology. The specific name “ tomamorum ” means “belonging to the Tomams.” Tomams are the highest level of deities recognized in the belief system of the indigenous Tolupan of Honduras, of which there are four: Tomam Pones Popawai (Grandfather Tomam), his wife Tomam Pones Namawai (mother of all that exists), and their children Tomam the Elder and Tomam the Younger ( Chapman 1992). This name is given in recognition that the Tolupan are the traditional inhabitants of this area and that this new species is known only from the Cordillera Nombre de Dios, or “Name of God Mountains,” a name which, ironically, was given by 15th century Spanish explorers.
Natural history. The single known specimen of Nototriton tomamorum was collected during the daytime from leaf litter packed onto a rock ledge alongside a small creek at about 1550 m elevation in the Lower Montane Wet Forest formation ( Fig. 5 View FIGURE 5 ). This species is presumably endemic to the vicinity of the type locality, and is likely restricted to the Lower Montane Wet Forest around the neighboring peaks of Cerro San Francisco and Cerro Texiguat. The locality can be characterized as a narrow, steep-sided canyon with riparian forest, and more xeric upland pine-oak forest dominating the terrain above the canyon. The pine-oak forest transitions to mesic cloud forest (or remnant cloud forest) uphill from this locality. This species is sympatric with a congener, N. barbouri , and three other plethodontids: Bolitoglossa dofleini , Bolitoglossa porrasorum and Oedipina gephyra . The canyon where the holotype of N. tomamorum was collected is also the type locality of the hylid frog Isthmohyla insolita , and a known locality for the anurans Lithobates maculatus , Plectrohyla guatemalensis , and Ptychohyla spinipollex .
Conservation status. Based on the criteria of the IUCN (2001), Nototriton tomamorum should be classified as Critically Endangered (B1ab[iii]+2ab[iii]) due to the extremely limited extent of its known distribution and the direct threat to the remaining habitat around that locality. The primary threat to the type and only known locality for this species is from illegal timber extraction and wholesale slash-and-burn clearing of forest for bean cultivation once it has been depleted of valuable hardwoods, such as mahogany ( Fig. 6 View FIGURE 6. A ).
Systematic relationships. Nototriton tomamorum bears the strongest morphological resemblance to members of the N. richardi group ( Table 2 View TABLE 2 ), which are endemic to the central highlands of Costa Rica. The two species, N. richardi and N. tapanti , are the most morphologically distinctive members of the genus, differing from all other Nototriton by having syndactylous feet, relatively large nostrils, and frontal processes of the premaxillary arising separately from the maxillary ( Good & Wake 1993; Papenfuss & Wake 1987; Savage 2002). According to Savage (2002), N. richardi is distributed from 1370 to 1800 m elevation along the Atlantic slope of the Cordillera Central, and N. tapanti at a single locality at 1300 m elevation in the northern portion of the Cordillera de Talamanca. These localities are situated in the central montane spine of Costa Rica in Lower Central America and are separated widely from the type locality of N. tomamorum by over 670 airline km and much of the central highlands of Honduras and the lowland Nicaraguan Depression. Despite the morphological similarities between N. tomamorum and members of the N. richardi group, our phylogenetic analysis ( Fig. 4 View FIGURE 4 ) does not support the inclusion of N. tomamorum in the N. richardi group. Preliminary phylogenetic analysis of fragments from two mitochondrial genes (16S and cob) weakly supports (posterior probability = 0.55, bootstrap support = 58%) N. tomamorum as sister taxon to the rest of the N. barbouri group ( Fig. 4 View FIGURE 4 ). We also recovered N. richardi as the weakly supported sister (posterior probability = 0.58, bootstrap support = 59%) to the N. picadoi group, a finding consistent with previous phylogenetic hypotheses for Nototriton and N. richardi ( García-París & Wake 2000; Wiens et al. 2007; Adams et al. 2009).
Sequence data from the holotype of Nototriton tomamorum are at least 12.5% (16S) and 20.6% (cob) divergent from representatives of morphologically-similar genera of Central American plethodontids ( Cryptotriton , Dendrotriton , and Oedipina ), but less than 6.0% (16S) and 15.1% (cob) divergent from other species of Nototriton , supporting placement of N. tomamorum in this genus (Table 3). Within the genus Nototriton , the new species demonstrates differing patterns of sequence divergence on the two genes sampled. For 16S, N. tomamorum is closest to N. limnospectator (3.6–3.8%), a biogeographically-logical situation given the relative geographical proximity of RVS Texiguat to the type locality of N. limnospectator , approximately 100 airline km to the WSW in Parque Nacional Montaña de Santa Bárbara; however N. tomamorum is 12.4% divergent from N. limnospectator for cob, and for that gene is closer to the Costa Rican species N. abscondens (10.2%) and N. gamezi (11.5%) than to any other member of the N. barbouri group (Table 3).
Given the morphological differentiation and lack of strong phylogenetic support, we refrain from assigning N. tomamorum to any recognized species group pending acquisition and analysis of additional molecular data from mitochondrial and nuclear genes.
Our phylogenetic analyses included taxa and populations of Nototriton not available in previous studies ( García-París & Wake 2000; Wiens et al. 2007), including a sample from the vicinity of the type locality of N. barbouri (“Portillo Grande, Yoro, Honduras ” [ Schmidt 1936]). Inclusion of these data reveals the taxon N. barbouri to be paraphyletic ( Fig. 4 View FIGURE 4 ), with strong support for N. barbouri sensu stricto as the sister species of N. limnospectator and for the remaining populations assigned to N. barbouri (N. sp. in Fig 4 View FIGURE 4 ) from the Cordillera Nombre de Dios to be sister to N. brodiei from NE Guatemala and NW Honduras. We are currently preparing an intergrative systematic revision of the N. barbouri group that will use molecular and morphological analyses to resolve the taxonomic status of populations assigned to N. barbouri .
The herpetofauna of the RVS Texiguat is characterized by a remarkable degree of endemism ( McCranie & Castañeda 2004a; Wilson & McCranie 2004b). Currently, 39 species are known from 1550 m in elevation and above in this refuge. Of this number, 27 are considered to be conservation priority species ( Table 4 View TABLE 4 ), defined as those species judged to occupy one of three IUCN categories Critically Endangered, Endangered, or Vulnerable. Nine of the 27 are considered Critically Endangered, 12 are Endangered, and six are Vulnerable; 19 (70.4%) of these species (four salamanders, seven anurans, four lizards, and four snakes) are endemic to Honduras ( Table 4 View TABLE 4 ). Of the remainder, six are endemic to Nuclear Central America and two have widespread distributions. As indicated by Townsend & Wilson (In press), 91 species of amphibians and reptiles are endemic to Honduras, thus the Texiguat figure is 20.9% of the total. Therefore, RVS Texiguat qualifies as a major center of endemism in Honduras, as well as in the whole of eastern Nuclear Central America (as defined by Campbell, 1999). The Environmental Vulnerability Scores, as tabulated by Townsend and Wilson (in press) and indicated in Table 4 View TABLE 4 , indicate that the values for the Texiguat conservation priority species range from 9 to 17. Most of these species involved (16) are considered high vulnerability species (59.3%), nine (33.3%) are medium vulnerability species, and only two (7.4%) have scores lying at the upper end of the range for low vulnerability species ( Table 4 View TABLE 4 ). In summary, of the 27 species judged to be of conservation priority, 19 are endemic to Honduras and 16 are of high vulnerability. Based on the analysis above, Refugio de Vida Silvestre Texiguat is an area of immense importance for the conservation of the Honduran herpetofauna, especially its endemic component.
Unfortunately, little attention has been paid to RVS Texiguat by conservation authorities past its initial designation as a protected area in 1987 ( Wilson et al. 2001). Since 1991, ten species (including the present one) with type localities in the area have been described: Anolis kreutzi , A. purpurgularis , A. yoroensis , Celestus scansorius , Geophis damiani , Isthmohyla insolita , Nototriton tomamorum , Oedipina gephyra , Omoadiphas texiguatensis , and Rhadinaea tolpanorum ( McCranie et al. 1993a, b; Wilson et al. 1998; McCranie & Castañeda 2004a). Given the pattern of these finds, we expect that additional new taxa remain to be described from RVS Texiguat. During this period, significant environmental damage has been observed, most of it apparently as a consequence of the illegal extraction of mahogany and the subsequent conversion of the remaining forest to cropland for use in subsistence agriculture ( Fig. 6 View FIGURE 6. A ). Most recently during our visit in April 2008, we observed that a large stretch of forest upstream from the type locality of Nototriton tomamorum and Isthmohyla insolita had been clear-cut down to the streamside and planted to beans ( Fig. 6 View FIGURE 6. A C).
Damage to the forests in this refuge also has occurred by natural means. The stream that constitutes the type locality of Nototriton tomamorum and Isthmohyla insolita ( Fig. 5 View FIGURE 5 ) was severely damaged by Hurricane Mitch in 1998. At that time, the habitat supporting I. insolita was scoured by high waters in the narrow canyon. The moss masses clinging to the branches of small trees overhanging the stream, within which the adults laid their eggs, were stripped away. Our trip in 2008 evidenced that the moss has yet to be reestablished as we found it in 1991 when I. insolita was discovered. Whether the reestablishment of these conditions will occur is doubtful. Isthmohyla insolita has been located in one or two nearby streams ( McCranie & Castañeda 2007), but the same anthropogenic activities detailed above also are occurring there.
It is apparent that the natural habitat of this hotspot for herpetofaunal endemism will continue to succumb to the forces of habitat destruction unless steps are taken to protect it. Therefore, we use this opportunity not only to describe yet another endemic species from this reserve, but to attempt to raise RVS Texiguat’s international profile and issue an urgent call for its conservation. We offer the following recommendations, and emphasize the need for immediate and sustained action to prevent further loss of habitat:
Carry out intensive reconnaissance of RVS Texiguat on the Caribbean side of Cerro Texiguat and Cerro San Francisco, to search for and identify previously unknown areas supporting populations of conservation priority species. The majority of work in RVS Texiguat has taken place in the vicinity of La Fortuna, which is accessed by means of a logging road established sometime before 1991. The Caribbean slope of RVS Texiguat remains virtually unexplored and has no known access routes, and so exploratory work is needed immediately to determine if this areas supports target species.
Establish a habitat and species monitoring program led by Honduran biologists and local guardarecursos. This program has been initiated in cooperation with PROLANSATE (the organization tasked with managing RVS Texiguat). Initial plans are to hire six guardarecursos in early 2010 and begin training and capacity building for development of long-term monitoring teams.
Identify means of mitigating illegal logging and subsequent habitat destruction on the southern side of the RVS Texiguat. The extraction of high-value hardwoods from RVS Texiguat by way of the drier southern side of the mountain is well established and obviously influences the local economy; the subsequent clearing of relatively large plots of forest for cultivation of beans appears to be the work of relatively few individuals. While legal action against these actors is unlikely, identification of the most influential of these stakeholders and initiation of a dialogue with them is the first step toward mitigating the destruction of remaining habitat in the vicinity of La Fortuna.
Initiate public outreach and environmental education projects in buffer zone communities. Awareness of the unique nature and value of the biodiversity RVS Texiguat, or even the very existence of the reserve as a legal entity, is virtually non-existent. Any scientific-based conservation efforts need to be supported by efforts to empower local actors through education and capacity building, in an attempt to engender a local desire to conserve the natural resources of RVS Texiguat for the foreseeable future.
If these steps are not taken, it is likely that this significant center of herpetofaunal endemism will succumb to the pressures of severe, and largely unnecessary, environmental degradation. Given that fully one-fifth of Honduras’ endemic herpetofauna occurs in RVS Texiguat, this simply cannot be allowed to happen.
TABLE 2. Morphological and morphometric comparison of species of Nototriton; see Material and Methods section for explanation of abbreviations; SVL is given in mm. Comparative morphological data for species other than N. tomamorum are from Good & Wake (1993), Campbell & Smith (1998), McCranie et al. (1998), Ehmcke & Clemen (2000), Wake & Campbell (2000), Köhler (2002), McCranie & Wilson (2002), Savage (2002).
| Species | SVL | HW/SVL | TL/SVL | HLL/SVL | FLL/SVL | HFW/SVL | NL/SVL | MT | VT |
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| N. tomamorum sp. nov. | 26.9 | 0.145 | 0.911 | 0.197 | 0.160 | 0.037 | 0.018 | 26 | 11 |
| N. barbouri group | |||||||||
| N. barbouri | 30.2–39.9 | 0.104–0.132 | 1.031–1.398 | 0.153–0.200 | 0.142–0.174 | 0.037–0.060 | 0.005–0.011 | 41–54 | 12–23 |
| N. brodiei | 33.2–34.5 | 0.120 | 1.420–1.440 | 0.166–0.180 | 0.148–0.151 | 0.040–0.060 | 0.004–0.005 | 60–62 | 23–24 |
| N. lignicola | 28.3–33.9 | 0.103–0.118 | 0.840–1.059 | 0.158–0.181 | 0.137–0.160 | 0.029–0.040 | 0.006–0.009 | 46–54 | 16–24 |
| N. limnospectator | 33.0–38.2 | 0.095–0.118 | 1.027–1.297 | 0.164–0.211 | 0.156–0.183 | 0.048–0.061 | 0.003 | 42–55 | 16–26 |
| N. stuarti | 32.6 | 0.138 | 1.264 | 0.178 | 0.172 | 0.049 | 0.012 | 36 | 20 |
| N. richardi group | |||||||||
| N. richardi | 21.0–24.0 | 0.126–0.150 | 1.072–1.482 | 0.174–0.187 | 0.140–0.146 | 0.044–0.050 | 0.012–0.016 | 24 | 16 |
| N. tapanti | 23.5 | 0.129 | 1.205 | 0.174 | 0.147 | 0.041 | 0.013 | 31 | 14 |
| N. picadoi group | |||||||||
| N. abscondens | 21.0–33.0 | 0.121–0.143 | 1.013–1.365 | 0.157–0.206 | 0.148–0.183 | 0.058–0.071 | 0.003–0.014 | 27–38 | 8–11 |
| N. gamezi | 23.6–26.2 | 0.130–0.140 | 1.10–1.30 | 0.160–0.170 | 0.152 | 0.061 | 0.007 | 24–35 | 12–17 |
| N. guanacaste | 18.2–29.7 | 0.145–0.157 | 1.210–1.337 | 0.185–0.201 | 0.170–0.179 | 0.066–0.072 | 0.004–0.009 | 25–49 | 10–18 |
| N. major | 37.9 | 0.113 | 1.441 | 0.174 | 0.148 | 0.059 | 0.003 | 33 | 18 |
| N. picadoi | 20.0–32.0 | 0.123–0.144 | 1.203–1.424 | 0.180–0.189 | 0.169–0.182 | 0.060–0.070 | 0.010–0.016 | – | – |
| N. saslaya | 28.1–34.6 | 0.133–0.155 | 0.883–1.255 | 0.217–0.244 | 0.194–0.210 | 0.075–0.091 | 0.002–0.003 | 17–22 | 3–11 |
TABLE 4. Summary of conservation priority amphibian and reptiles from Reserva de Vida Silvestre Texiguat; distribution is characterized as Endemic (restricted to Honduras), NCA (restricted to Nuclear Central America), or Widespread (range extending outside of NCA); IUCN Red List status abbreviations are CR (Critically Endangered), EN (Endangered), VU (Vulnerable); methods for calculating Environmental Vulnerability Score are detailed in the Materials and Methods section.
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