skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Comparative cranial osteology of European gekkotans (Reptilia, Squamata)
Comparative osteology of European lizards, and of European geckos in particular, is poorly known, resulting in problems when trying to determine to species isolated bones found as fossils or as remains of prey in scats or pellets. In order to partly solve this issue, we here present a detailed comparative analysis of the cranial bones of the four most broadly distributed species of European gekkotans: Euleptes europaea, Hemidactylus turcicus, Mediodactylus kotschyi and Tarentola mauritanica. The skulls of these species display both a set of features that are typical for geckos in general and unique features that can be employed to identify isolated bones of all considered species. Diagnostic differences are found in almost every bone (except the squamosal, epipterygoid and stapes), leading to the creation of a detailed diagnostic key. The dentition also displays some interspecific differences, even though all four species share a similar general tooth morphology, with pleurodont teeth provided with two parallel cutting edges separated by a groove-like space. Such a dentition is consistent with an arthropod-based diet.  more » « less
Award ID(s):
1657656
PAR ID:
10092688
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Zoological journal of the Linnean Society
Volume:
184
Issue:
3
ISSN:
0024-4082
Page Range / eLocation ID:
857 - 895
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract How developmental modifications produce key innovations, which subsequently allow for rapid diversification of a clade into new adaptive zones, has received much attention. However, few studies have used a robust comparative framework to investigate the influence of evolutionary and developmental constraints on the origin of key innovations, such as the adhesive toe pad of lizards. Adhesive toe pads evolved independently at least 16 times in lizards, allowing us to examine whether the patterns observed are general evolutionary phenomena or unique, lineage-specific events. We performed a high-resolution comparison of plantar scale development in 14 lizard species in Anolis and geckos, encompassing five independent origins of toe pads (one in Anolis, four in geckos). Despite substantial evolutionary divergence between Anolis and geckos, we find that these clades have undergone similar developmental modifications to generate their adhesive toe pads. Relative to the ancestral plantar scale development, in which scale ridges form synchronously along the digit, both padded geckos and Anolis exhibit scansor formation in a distal-to-proximal direction. Both clades have undergone developmental repatterning and, following their origin, modifications in toe pad morphology occurred through relatively minor developmental modifications, suggesting that developmental constraints governed the diversification of the adhesive toe pad in lizards. 
    more » « less
  2. 1935 gecko species (and 224 subspecies) were known in December 2019 in seven families and 124 genera. These nearly 2000 species were described by ~950 individuals of whom more than 100 described more than 10 gecko species each. Most gecko species were discovered during the past 40 years. The primary type specimens of all currently recognized geckos (including subspecies) are distributed over 161 collections worldwide, with 20 collections having about two thirds of all primary types. The primary type specimens of about 40 gecko taxa have been lost or unknown. The phylogeny of geckos is well studied, with DNA sequences being available for ~76% of all geckos (compared to ~63% in other reptiles) and morphological characters now being collected in databases. Geographically, geckos occur on five continents and many islands but are most species-rich in Australasia (which also houses the greatest diversity of family-level taxa), Southeast Asia, Africa, Madagascar, and the West Indies. Among countries, Australia has the highest number of geckos (241 species), with India, Madagascar, and Malaysia being the only other countries with more than 100 described species each. As expected, when correcting for land area, countries outside the tropics have fewer geckos. 
    more » « less
  3. Gekkota (geckos and pygopodids) is a clade thought to have originated in the Early Cretaceous and that today exhibits one of the most remarkable scansorial capabilities among lizards. Little information is available regarding the origin of scansoriality, which subsequently became widespread and diverse in terms of ecomorphology in this clade. An undescribed amber fossil (MCZ R–190835) from mid-Cretaceous outcrops of the north of Myanmar dated at 99 Ma, previously assigned to stem Gekkota, preserves carpal, metacarpal and phalangeal bones, as well as supplementary climbing structures, such as adhesive pads and paraphalangeal elements. This fossil documents the presence of highly specialized adaptive structures. Here, we analyze in detail the manus of the putative stem Gekkota. We use morphological comparisons in the context of extant squamates, to produce a detailed descriptive analysis and a linear discriminant analysis (LDA) based on 32 skeletal variables of the manus. The comparative sample includes members of 15 extant squamate families (Agamidae, Dactyloidae, Iguanidae, Leiosauridae, Liolaemidae, Polychrotidae, Tropiduridae, Diplodactylidae, Eublepharidae, Gekkonidae, Phyllodactylidae, Sphaerodactylidae, Gymnophthalmidae, Teiidae, and Scincidae). Although the fossil manus is qualitatively more similar to that of members of Gekkota, the LDA analysis places it in a morphozone shared by Gekkota and Scincomorpha. This result is particularly interesting, given that despite the presence of paraphalangeal structures had only been reported in extant geckos of the families Gekkonidae and Phyllodactylidae, the usage of an adhesive subdigital system to climb originated independently in Gekkota, Scincidae, and Dactyloidae. 
    more » « less
  4. The Peruvian sphaerodactyl gecko, Pseudogonatodes barbouri, is among the smallest reptile species in South America. Morphological information about this species, or even the genus, is limited. In this study, we produced a bone-by-bone description from the skull and atlantoaxial complex to contribute new phenotypic information about this poorly known lizard. To achieve this objective, we employed a divide-and-conquer approach in which each author digitally isolated one or two bones from the skull and produced a written description of these elements, thereby reducing 3D imaging processing and description to a fraction of time. In addition to a reduced phalanx in the fourth toe of both the hand and foot, the genus is characterized by having nasal bones with a broad lateral wing, an ectopterygoid that clasps the pterygoid, and an anterior shifting of the paroccipital process and as consequence the position of the quadrate, and squamosal not participating in the quadrate suspension. There are also modifications in fenestration and foramina and a trend towards synostosis of the jaw bones (e.g., coronoid + splenial, compound bone + surangular). Pseudogonatodes bears four long processes on the intercentrum of the axis; which is a character of New World sphaerodactyls. 
    more » « less
  5. Studies of the Caribbean herpetofauna (amphibians and reptiles) have made significant contributions to our knowledge of evolutionary patterns and processes. A prerequisite for these studies are accurate taxonomies and robust phylogenetic hypotheses. One notable Caribbean radiation lacking such data are dwarf geckos of the genus Sphaerodactylus. Systematics of the Puerto Rican Sphaerodactylus have been turbulent since the initial species descriptions and no molecular phylogenies exist that include complete or near-complete taxon sampling. Here, we combine a multi-locus molecular phylogeny with extensive morphological information to investigate the current diversity of Sphaerodactylus geckos from the Puerto Rican Bank, with a large number of species from Hispaniola as an outgroup. In particular, we focus our efforts on resolving the taxonomy of the Sphaerodactylus macrolepis Günther species complex. We find S. macrolepis sensu lato (currently two nominal species with nine subspecies) is made up of at least four diagnosable species within two clades: (1) the sister species Sphaerodactylus macrolepis sensu stricto from the Virgin Islands (including St. Croix) and Culebra, and S. parvus King from islands in the northern Lesser Antilles; and (2) all other Sphaerodactylus macrolepis subspecies from Puerto Rico, Vieques, and Culebra. We resurrect Sphaerodactylus grandisquamis Stejneger from synonymy to refer to all subspecies from Puerto Rico and elevate the subspecies Sphaerodactylus inigoi Thomas & Schwartz for geckos from Vieques and western Culebra. The resulting phylogeny and revised taxonomy will be a useful tool for subsequent research into Sphaerodactylus conservation and evolution. 
    more » « less