A New Species of Sphaerodactylus (Gekkota: Sphaerodactylidae) from the Northwest Limestone Region of Puerto Rico
Advances in both morphological and molecular techniques have uncovered many lineages across the tree of life, and Neotropical vertebrates are no exception. Sphaerodactylus geckos (Sphaerodactylidae) are abundant and important components of the Neotropical herpetofauna, but few studies have thoroughly investigated them using a combination of morphology and modern molecular genetic methods. Here, we combine morphological and genetic data to describe a new species of Sphaerodactylus from the northwestern karst region of Puerto Rico. The new species is compared to other closely related and sympatric species of Sphaerodactylus. Morphological analysis shows that the combination of small body size (median SVL = 21.5 mm), lepidosis, skull morphology, and coloration of the head differentiates the new species from its closest relatives, including the related species, Sphaerodactylus klauberi. Comparing sequences of the mitochondrial 16S rRNA gene showed a genetic distance between S. klauberi and the new species of 5.1–5.6%, which is similar to genetic distances among other recognized gecko species. This is the first new species of Sphaerodactylus to be described from Puerto Rico in nearly a century, highlighting the continued need to evaluate and chronicle biological diversity even in well-studied regions. Las filogenias moleculares han elucidado múltiples linajes en el árbol de la vida, incluyendo varios vertebrados neotropicales. Las salamanquitas del género Sphaerodactylus (Sphaerodactylidae) son abundantes y forman una parte importante de la herpetofauna neotropical. Este género ha sido investigado recientemente utilizando métodos moleculares modernos. En este artículo se describe una nueva especie del género Sphaerodactylus, procedente de la región kárstica del noroeste de Puerto Rico. Los individuos de la nueva especie fueron comparados con especies afines y simpátricas. El análisis morfológico muestra que la combinación entre el tamaño corporal, escamación, morfología del cráneo y coloración cefálica, distinguen a la especie nueva de otras especies cercanas filogenéticamente, incluyendo su especie hermana Sphaerodactylus klauberi. Al comparar secuencias del gen mitocondrial 16S rRNA se observó una distancia genética de 5.1–5.6% entre la especie nueva y S. klauberi, dicha distancia es similar a la que existe entre otras especies descritas de salamaquitas. Ha pasado casi un siglo desde que la última especie de Sphaerodactylus de Puerto Rico fue descrita, ésto resalta la necesidad de seguir evaluando y catalogando la biodiversidad, inclusive en áreas que han sido investigadas a profundidad.
Proposed distribution of Sphaerodactylus verdeluzicola, new species. Orange symbols represent the proposed distribution of the new species; green and pink symbols denote distribution of S. klauberi. Circles indicate records from museum databases (Sphaerodactylus klauberi in GBIF Secretariat, 2020). Scale bar in mm applies to all pictures of geckos. Museum specimens were examined to confirm if they match the description of the new species. Squares indicate visited localities. 1) Rincón, 2) Isabela, 3) Camuy, 4) Bosque Estatal de Río Abajo, 5) Arecibo, 6) Florida, 7) Maricao, 8) Adjuntas, 9) Toro Negro, 10) Divisoria, 11) Orocovis-Villalba, 12) Bosque Estatal de Carite, 13) El Toro trail.
Dorsal and ventral view of Sphaerodactylus verdeluzicola from two localities. Rincón: (A–B) MPM-RA34017, female; (C–D) MPM-RA34016, male, holotype; (E–F) MPM-RA34018, female. Bosque Estatal de Río Abajo: (G–H) MPM-RA34019, male.
Live coloration of Sphaerodactylus verdeluzicola. Above, a male specimen from Bosque Estatal de Río Abajo. Below, a female specimen from Rincón.
Phylogenetic relationships among a subset of Puerto Rican species of Sphaerodactylus. Maximum likelihood phylogeny constructed using mitochondrial 16S rRNA gene sequences with UFBoot values ≥95 adjacent to respective branches. Bayesian posterior probabilities ≥0.95 are indicated by black circles at nodes. Sequences of Sphaerodactylus verdeluzicola are highlighted by the gray box. Outgroup taxa (Table 1) pruned for clarity. See Data Accessibility for tree file.
Dot-box plot of SVL range between males and females of S. verdeluzicola and S. klauberi. Digital X-rays of the holotype of Sphaerodactylus klauberi (USNM 120719, left) and one specimen of S. verdeluzicola (MPM-RA34016, right) were added to the figure as a visual reference of the size difference between the two species.
Pectoral scales of Sphaerodactylus verdeluzicola and S. klauberi. Smooth scales in a specimen from Rincón (TG 2645, left), faintly keeled scales from a Bosque Estatal de Río Abajo individual (JDD 048, middle), and proportionally larger and strongly keeled scales in S. klauberi (TG 2758) from El Yunque (right).
Skull high resolution computed tomography images of Sphaerodactylus verdeluzicola and S. klauberi. (A–C) Sphaerodactylus verdeluzicola from Rincón (MPM-RA34016, holotype); (D–F) Sphaerodactylus klauberi from El Yunque (JDD 449). Notice the poorly ossified region along the tooth-bearing bones in S. klauberi; this phenomenon was present in both CT scanned specimens from El Yunque.
Full body high resolution computed tomography of Sphaerodactylus klauberi and S. verdeluzicola. (A–B) Sphaerodactylus klauberi from the type locality—El Yunque (JDD 449); (C–D) S. verdeluzicola from Rincón (MPM-RA34016); (E–F) S. verdeluzicola from Bosque Estatal de Río Abajo (MPM-RA34019, male). (1) Indicates a clavicular fenestra, completely enclosed on bone; (2) indicates a nearly emarginate clavicular fenestra. Right clavicle of (G) S. klauberi (JDD 449) and (H) S. verdeluzicola (MPM-RA34019) showing the difference in size and position of the clavicular fenestra and the clavicular foramen.
Contributor Notes
Associate Editor: B. L. Stuart.