Abstract:Tarentola annularis is a climbing gecko with a wide distribution in Africa north of the equator. In the present paper, we describe the development of the osteocranium of this lizard, from the first appearance of the cranial elements up to the point of hatching. This is based on a combination of histology and cleared and stained specimens. This is the first comprehensive account of gekkotan pre‐hatching skull development based on a comprehensive series of embryos, rather than a few selected stages. Given that G… Show more
“…However, even among other gekkotans that lay rigid-shelled eggs incubation periods are not as long as that observed in G. darwinii (e.g. Domingos et al, 2017;Khannoon & Evans, 2020;Kluge, 1967;Somaweera, 2009), highlighting another interesting trait in the reproductive biology of this species.…”
We present information on the reproduction of Gymnodactylus darwinii based on macroscopic analysis of its gonads. We found no sexual dimorphism in body size (SVL) between adult males and females, but males had, on average, wider heads and longer forearms. Both sexes had very similar sizes at sexual maturity and maximum body sizes, suggesting male–male competition for resources does not occur, and/or there are no sexual differences in survival rates. The smallest specimen had 24 mm SVL, and juvenile/immature specimens of similar or slightly bigger sizes were collected throughout the year suggesting a continuous turnover of individuals in the population. Adult males showed a continuous reproductive cycle, contrasting with a seasonal cycle of females, where maximum gonadal volume was observed from September to December. This is not uncommon and may be related to differential response to local environmental conditions, or because distinct investment in reproduction. Females have a small and fixed clutch size (two eggs per clutch), a pattern also observed in its congener G. amarali and in many geckonids, which is likely due to phylogenetic inertia. To compensate for a fixed clutch size, females may be able to lay more than one clutch per reproductive season.
“…However, even among other gekkotans that lay rigid-shelled eggs incubation periods are not as long as that observed in G. darwinii (e.g. Domingos et al, 2017;Khannoon & Evans, 2020;Kluge, 1967;Somaweera, 2009), highlighting another interesting trait in the reproductive biology of this species.…”
We present information on the reproduction of Gymnodactylus darwinii based on macroscopic analysis of its gonads. We found no sexual dimorphism in body size (SVL) between adult males and females, but males had, on average, wider heads and longer forearms. Both sexes had very similar sizes at sexual maturity and maximum body sizes, suggesting male–male competition for resources does not occur, and/or there are no sexual differences in survival rates. The smallest specimen had 24 mm SVL, and juvenile/immature specimens of similar or slightly bigger sizes were collected throughout the year suggesting a continuous turnover of individuals in the population. Adult males showed a continuous reproductive cycle, contrasting with a seasonal cycle of females, where maximum gonadal volume was observed from September to December. This is not uncommon and may be related to differential response to local environmental conditions, or because distinct investment in reproduction. Females have a small and fixed clutch size (two eggs per clutch), a pattern also observed in its congener G. amarali and in many geckonids, which is likely due to phylogenetic inertia. To compensate for a fixed clutch size, females may be able to lay more than one clutch per reproductive season.
“…Another possible factor shaping the modularity of lizard skulls is the difference in ossification sequence patterns. It appears that the ossification sequences of lizard skulls by Khannoon & Evans 26 and the modular pattern of lizards in this study lacks any correlations (Fig. 5 ).…”
Section: Discussionmentioning
confidence: 55%
“… Figure 5 Comparison of ossification sequence and modularity of lizard skulls. These figures are based on comparing the ossification sequence by Khannoon & Evans 26 in the developmental stages (blue values) according to Dufaure and Hubert 51 . The ossification sequence patterns with the modules of the same family are compared, respectively 26 , 52 – 54 .…”
The morphology of lizard skulls is highly diverse, and it is crucial to understand the factors that constrain and promote their evolution to understand how lizards thrive. The results of interactions between cranial bones reflecting these factors can be detected as integration and modularity, and the analysis of integration and modularity allows us to explore the underlying factors. In this study, the integration and modularity of the skulls of lizards and the outgroup tuatara are analyzed using a new method, Anatomical Network Analysis (AnNA), and the factors causing lizards morphological diversity are investigated by comparing them. The comparison of modular structures shows that lizard skulls have high integration and anisomerism, some differences but basically common modular patterns. In contrast, the tuatara shows a different modular pattern from lizards. In addition, the presence of the postorbital bar by jugal and postorbital (postorbitofrontal) also reflect various functional factors by maintaining low integration. The maintenance of basic structures due to basic functional requirements and changes in integration within the modules play a significant role in increasing the morphological diversity of the lizard skull and in the prosperity of the lizards.
“…The ossification sequences are often considered conserved among squamates (e.g., Khannoon & Evans, 2020) and reptiles (e.g., Chapelle et al, 2020) or even tetrapods (Schoch, 2006) basioccipital; bs, basisphenoid; co, coronoid; d, dentary; en, calcified endolymph; ept, epipterygoid; f, frontal; mx, maxilla; n, nasal; ot, otooccipital; p, parietal; pmx, premaxilla; pof, postorbitofrontal; prf, prefrontal; pro, prootic; pt, pterygoid; san, surangular; so, supraoccipital; sq, squamosal sent in iguanian (e.g., Ollonen et al, 2018), gekkotan (Rieppel, 1994 and this work), scincoid (e.g., Hugi et al, 2012), lacertiform (e.g., -Jaimes et al, 2012;Roscito & Rodrigues, 2012), and anguimorph (e.g., Good, 1995;Werneburg et al, 2015) lizards, as well as in many snakes (e.g., Buchtová et al, 2007;Polachowski & Werneburg, 2013) (see Table S1 for a full list). Because of this, the pterygoid was reconstructed to be ancestrally the first ossifying bone in squamates (Werneburg et al, 2015;Werneburg & Sánchez-Villagra, 2015), a conclusion supported by our data.…”
Gekkotans are one of the major clades of squamate reptiles. As one of the earliest‐diverging lineages, they are crucial in studying deep‐level squamate phylogeny and evolution. Developmental studies can shed light on the origin of many important morphological characters, yet our knowledge of cranial development in gekkotans is very incomplete. Here, we describe the embryonic development of the skull in a parthenogenetic gekkonid, the mourning gecko (Lepidodactylus lugubris), studied using non‐acidic double staining and histological sectioning. Our analysis indicates that the pterygoid is the first ossifying bone in the skull, as in almost all other studied squamates, followed closely by the surangular and prearticular. The next to appear are the dentary, frontal, parietal and squamosal. The tooth‐bearing upper jaw bones, the premaxilla and maxilla, develop relatively late. In contrast to previous reports, the premaxilla starts ossifying from two distinct centres, reminiscent of the condition observed in diplodactylids and eublepharids. Only a single ossification centre of the postorbitofrontal is observed. Some of the endochondral bones of the braincase (prootic, opisthotic, supraoccipital) and the dermal parasphenoid are the last bones to appear. The skull roof is relatively poorly ossified near the time of hatching, with a large frontoparietal fontanelle still present. Many bones begin ossifying relatively later in L. lugubris than in the phyllodactylid Tarentola annularis, which suggests that its ossification sequence is heterochronic with respect to T. annularis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
