Editorial Type:
Article Category: Research Article
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Online Publication Date: 11 Jun 2021

Molecular Phylogenetics and Morphometrics Reveal a New Endemic Jumping Pitviper (Serpentes: Viperidae: Metlapilcoatlus) from the Sierra Madre Oriental of Mexico

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Page Range: 181 – 191
DOI: 10.1670/20-028
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ABSTRACT

The jumping pitvipers of the genus Metlapilcoatlus are generally associated with montane environments and are widely distributed from central and southern Mexico to Panama. In this study, we analyzed the phylogenetic position and compared the morphology of a population from the Sierra Madre Oriental, within the Sierra Gorda Biosphere Reserve, to other species of jumping pitvipers. We implemented two mtDNA gene fragments (cyt b and ND4) of 50 specimens of the five Metlapilcoatlus species for phylogenetic reconstruction using Bayesian inference and maximum likelihood. We used a linear discriminant analysis and comparative statistics of external and hemipenial characters to assess the morphological differences among Metlapilcoatlus lineages. Our analyses support a strong genetic and morphological distinction of Metlapilcoatlus nummifer populations established to the north of the Trans-Mexican Volcanic Belt (Hidalgo, Northern Veracruz, and Querétaro) from other Metlapilcoatlus taxa. Based on this evidence we describe the populations from the north as a new species.

RESUMEN

Las víboras saltadoras del género Metlapilcoatlus generalmente están asociadas con ambientes de montaña y se encuentran ampliamente distribuidas desde el centro y sur de México hasta Panamá. En este estudio, analizamos la posición filogenética y comparamos la morfología de una población de la Sierra Madre Oriental, dentro de la Reserva de la Biosfera Sierra Gorda, con otras especies de víboras saltadoras. Utilizamos dos fragmentos de genes de ADNmt (cyt b y ND4) de 50 especímenes de las cinco especies de Metlapilcoatlus para reconstrucciones filogenéticas utilizando inferencia bayesiana y máxima verosimilitud. Utilizamos un análisis discriminante lineal y estadísticas comparativas de caracteres externos y hemipeniales para evaluar las diferencias morfológicas entre los linajes de Metlapilcoatlus. Nuestros análisis respaldan una distinción genética y morfológica de las poblaciones de M. nummifer establecidas al norte de la Faja Volcánica Transmexicana (Hidalgo, Norte de Veracruz y Querétaro) de otros taxones de Metlapilcoatlus. Con base en esta evidencia, describimos las poblaciones del norte como una nueva especie.

Copyright: Copyright 2021 Society for the Study of Amphibians and Reptiles 2021
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Fig. 1.
Fig. 1.

Distribution map of the specimens used in this study for morphological and molecular analysis of Metlapilcoatlus spp. in Mexico and Central America. Bolded icons represent type localites for each species. Shaded regions represent the Transmexican Volcano Belt (TVB).

Fig. 2.
Fig. 2.

Discriminant analysis performed to determine morphological variation between the six species of Metlapilcoatlus.

Fig. 3.
Fig. 3.

Comparison of the main lepidotic characters used to differentiate between Metlapilcoatlus nummifer and Metlapilcoatlus sp. (A) Foveal scales (W = 32.5, P = 0.008), (B) intercanthal scales (W = 37, P = 0.01), (C) interoculabial scales (W = 150.5, P = 0.0007), (D) postorbital stripe height (W = 147, P = 0.002), (E) intersupraocular scales (W = 30, P = 0.004), (F) middorsal scale rows (W = 140.5, P = 0.001), (G) nasorostral scales (W = 43, P = 0.02), (H) scales contacting third supralabial (W = 32, P = 0.004).

Fig. 4.
Fig. 4.

Hemipenes of the species of the genus Metlapilcoatlus. First, the asulcate view is shown and the sulcate face of the hemipenes of each species is printed with a premium letter. (A) Metlapilcoatlus indomitus (UTA R-52952), (B) M. mexicanus (UTA R-45500), (C) M. nummifer (UTA R-24842), (D) M. olmec (UTA R-25113), (E) M. occiduus (UTA R-26415), and (F) Metlapilcoatlus sp. (MZFC 35382).

Fig. 5.
Fig. 5.

Phylogenetic relationships of the genus Metlapilcoatlus obtained through Bayesian inference (IB) and maximum likelihood (ML) function with the RAxML software. The condensed nodes (black) correspond to the genera used in the external group. All nodes are shown with a subsequent probability (PP) ≥ 90 except those indicated with an arrow. The values obtained through IB are shown, followed by the values obtained through ML (IB/ML). Names of specimens at terminals correspond to IDs given in Table 1 and Supplemental Material 4.

Fig. 6.
Fig. 6.

Distribution of the specimens analyzed in this study. (A) Distribution of all species of the genus Metlapilcoatlus from Costa Rica to Mexico and location of the specimens used of the species M. nummifer (black box, solid line). (B) The two northernmost clades formed by the specimens of M. borealis and M. nummifer are showed in the black box. Shaded region represent the Transmexican Volcano Belt (TVB).

Fig. 7.
Fig. 7.

(A) Metlapilcoatlus borealis specimen from the locality of San Juan de los Durán, in Jalpan de Serra, Querétaro, (B) dorsal view of the holotype of M. borealis, (C) ventral view of the holotype of M. borealis. All photographs correspond to MZFC-35381 from San Juan de los Durán, Municipality of Jalpan de Serra, Querétaro. Photographs by Óscar Flores-Villela (A) and Mauricio Tepos Ramírez (B and C).

Contributor Notes

2 Corresponding Author. E-mail: teposmauricio@gmail.com
Accepted: 07 Mar 2021
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