Cool Geckos: Does Plesiomorphy Explain Morphological Similarities between Geckos from the Southern Cone?
The South American genus Homonota comprises 10 species of Broad-Headed Geckos that reach the austral limit for the Gekkota. Historically, morphological data have supported the monophyly of a group including Homonota and the Chilean genus Garthia, with the latter possibly embedded within the former. In contrast, molecular evidence indicates these two genera to be in separate clades and that Homonota is more closely related to the Leaf-Toed Geckos of the genus Phyllodactylus. Here, we analyze 592 morphological characters in Garthia, Homonota, and additional phyllodactylid geckos to evaluate their morphological similarities. Our results indicate that Homonota and Garthia share a great majority of both external and internal characters and are nearly indistinguishable on morphological grounds. These results are interpreted in the light of a recently published multigene molecular phylogeny, and they suggest the symplesiomorphic retention of many morphological states linked to miniaturization and terrestriality in Garthia and Homonota, and concomitant differentiation of the American Leaf-Toed Geckos. El género Homonota del sur de América del Sur comprende diez especies de gecos de cabeza ancha, alcanzando el límite austral para los Gekkota. Históricamente, los datos morfológicos han apoyado la monofilia de un grupo que incluye Homonota y el género chileno Garthia, con la posibilidad de que el género anterior estuviese contenido en el primero. Por otro lado, la evidencia molecular reciente indica que éstos dos géneros forman dos clados separados y que Homonota está más cercano a los gecos con dedos en forma de hoja del género Phyllodactylus. En este trabajo, analizamos 592 caracteres morfológicos en Garthia, Homonota, además de otros de la familia Phllodactylidae con el propósito de evaluar las similitudes morfológicas. Nuestros resultados indican que Homonota y Garthia comparten la mayoría de caracteres externos e internos, y que son casi indistinguibles morfológicamente. Estos resultados son interpretados utilizando una filogenia molecular reciente de varios genes, y sugieren que Garthia y Homonota retienen una gran cantidad de simplesiomorfias, las cuales están asociadas a sus hábitos terrestres y a procesos de miniaturización, como también a su diferenciación de los gecos americanos con dedos de hoja.Abstract
Resumen
Distributions Garthia and Homonota. Modified from Kluge (1964) and Morando et al. (2014) with the addition of G. penai, H. rupicola, and new localities from literature (Vanzolini and Donoso-Barros, 1966; Marquet et al., 1990; Martori and Aun, 1994; Lions et al., 1997; Acosta and Murúa, 1998; Guerreiro et al., 2005; Cacciali et al., 2007; Pelegrin and Bucher, 2009; Troncoso-Palacios, 2014) and data from the Instituto de Herpetología, Fundación Miguel Lillo, Argentina. Question mark indicates an unconfirmed record of Garthia gaudichaudii in Bolivia in Kluge (1964). Photo by D. Baldo, Homonota fasciata from Fuerte Esperanza, Departamento General Güemes, Provincia del Chaco, Argentina.
Intergeneric relationships of Phyllodactylidae by using two data sets. (A) Results from partitioned maximum likelihood analysis of the concatenated molecular genetic data. Numbered nodes are referred to in text. (B) One of the MPTs obtained using morphological data. (C) A supertree obtained combining A and B, node numbers correspond to 1, Phyllodactylidae; 2, a mainly southern South America clade, with the exception of the more widespread genus Phyllodactylus; and 3, Homonota. Image of Homonota fasciata. Values on nodes represent bootstrap values.
(A) Ventral view of the trunk of Phyllodactylus wirshingi (CAS 175498). (B) Lateral view of the pelvis of Phyllopezus pollicaris (JFBM 15822).
Dorsal and lateral view of the skull of representatives from all phyllodactylid genera. (A–B) Asaccus elisae (CAS 218137). (C–D) Garthia gaudichaudii (UMMZ 111574). (E–F) Gymnodactylus geckoides (CAS 49397). (G–H) Haemodracon riebeckii (MCZ A-27255). (I–J) Homonota fasciata (CAS 84771). (K–L) Phyllodactylus baurii (CAS 09501). (M–N) Phyllopezus lutzae (MCZ R-46191). (O–P) Ptyodactylus hasselquistii (CAS 228536). (Q–R) Tarentola mauritanica (CAS 87112). (S–T) Thecadactylus rapicauda (CAS 95146). Scale bar = 5 mm. Photo inset: Homonota fasciata from Departamento Capital, Provincia de San Juan, Argentina. Photo taken in an urban dominated environment, courtesy of A. Laspiur.
Skull in dorsal and ventral view of Garthia and Homonota geckos. All drawings made at the same scale, skull length after specimen number. (A, E) Garthia penai (MZSP 60938; 11.7 mm). (B, F) H. andicola (FML uncatalogued; 11.4 mm). (C, G) H. darwinii (FML uncatalogued; 11.5 mm). (D, H) H. fasciata (FML 01495; 12.1 mm). (I, M) H. whitii (FML 03547; 11.1 mm). (J, N) H. uruguayensis (FML uncatalogued; 9.1 mm). (K, O) H. borellii (FML 00933; 9.95 mm). (L, P) H. underwoodi (FML uncatalogued; 11.8 mm). Numbers on the figure correspond to characters and character states described in the text.
Morphological characters of Garthia and Homonota. (A, B) Labial and lingual view of the jaw of Homonota darwinii (FML uncatalogued, 13.61 mm); scheme of the anterior portion of the snout, showing the shape of rostral scale, nostril size, form of rostral crease, and associated scales in (C) Homonota whitii and (D) Garthia gaudichaudii (redrawn from Kluge, 1964). Scale bar = 10 mm. Numbers on the figure correspond to characters and character states described in the text.
Presence (A, Garthia gaudichaudii, UMMZ 111574) and absence (B, Phyllodactylus baurii, CAS 09501) of the stapedial foramen in phyllodactylids. (C) Pelvic girdle of Homonota fasciata (JFBM 15827) showing an ischium wider than pubis in ventral view and a posterior flange of ischium notably concave. Abbreviations: isc, ischium; mp, metischial processes; of, obturator foramen; pp, pectineal process; pub, pubis; pv, pygial vertebrae series.
Dorsal view of phyllodactylid geckos. Values next to the specimen number indicate total length, skull length after specimen number. (A) Tarentola mauritanica (AMNH 71591; 18.30 mm). (B) Ptyodactylus hasselquistii (FMNH 210095; 21.08 mm). (C) Asaccus elisae (BMNH uncataloged; 17.84 mm). (D) Gymnodactylus geckoides (CAS 49397). (E) Phyllopezus pollicaris (FML 02313; 18.14 mm). (F) Phyllodactylus whirshingi (CAS 175498; 17.55 mm). (G) P. tuberculosus (BMNH 1906.6.1.220, 24.76 mm). (H) Labial side of the jaw of P. tuberculosus (BMNH 1906.6.1.220; 25.21 mm). Dashed lines in (C) represent inferred sutures.
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