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    Item-typ:Veröffentlichung,
    Subdigital integumentary microstructure in Cyrtodactylus (Squamata: Gekkota): do those lineages with incipiently expressed toepads exclusively exhibit adhesive setae?
    (Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2026-01)
    Ginal, Philipp
    ;
    Ecker, Yannick
    ;
    Higham, Timothy
    ;
    Grismer, L Lee
    ;
    Wipfler, Benjamin
    In taxa such as insects, spiders, bats, frogs, and lizards, adhesive structures at the distal ends of their limbs have independently evolved, enabling the animals to adhere to inclined or even inverted surfaces. The adhesive apparatus of geckos functions via a complex interaction among muscles, bones, vascular tissue, and microscopic epidermal microstructures. The microstructures of geckos are classifiable as spinules, spines, prongs and setae, but only setae, which possess spatulate tips, promote adhesive competency sufficient to support body mass employing van der Waals forces. Several studies indicate that the form of toepad microstructures might be specific to the exploitation of the attributes of the substrata employed during habitat use. The species-rich genus Cyrtodactylus exhibits extensive variation in the shape of the subdigital scales associated with different habitats, making it a promising candidate for studying toepad evolution. We investigated the subdigital microstructures of 27 Cyrtodactylus species occupying a wide range of habitats, and exhibiting a spectrum of subdigital morphology, from the presence of the ancestral condition of small, rounded scales to the early-stage development of macroscopically visible incipient toepads. Using SEM and phylogenetic comparative analyses, our objectives were to (a) clarify how integumentary microstructural traits relate to the presence of incipient toepads and (b) identify potential adaptations linked to specific habitat types. We hypothesized that (1) species showing incipient toepad development will possess setae, while those lacking obvious macrostructural modifications should exhibit only spines, prongs, or spinules. Additionally, we hypothesized that either (2) the presence of setae is associated with arboreal lifestyles and, to a lesser extent, with rock-dwelling ecotypes; or (3) alternatively, microstructural traits are more strongly influenced by phylogeny, with closely related species exhibiting more similar toepad features than those more distantly related. We found setae, spines, and prongs on the incipient toepads. Spines were found to be the ancestral subdigital microstructures of Cyrtodactylus, with multiple independent transitions to prongs (three times) and setae (twice). One shift towards setae defines a largely seta-bearing clade, exhibiting a strong phylogenetic signal and supports our third hypothesis. Most transitions to incipient toepads occurred within this clade, consistent with hypothesis 1, and we reveal that the evolution of setae likely preceded that of broadened scales. Although microstructure types did not significantly correlate with ecotype, specific morphometric traits varied significantly among both microstructure types and ecotypes.
    Wissenschaftlicher Artikel
    Band:17
      9
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    Item-typ:Veröffentlichung,
    Ecomorphology of the Locomotor Apparatus in the Genus Cyrtodactylus (Gekkota, Squamata)
    (Springer Nature, 2024-01)
    Riedel, Jendrian
    ;
    Grismer, L. Lee
    ;
    Higham, Timothy
    ;
    Wu, Joseph
    ;
    Do, Quyen Hanh
    Adaptive radiations garner considerable interest from evolutionary biologists. Lizard radiations diversifying along structural niche space often exhibit distinct changes in body and limb proportions. One prediction is that terrestrial species inhabiting open habitats will have relatively longer hindlimbs, associated with faster running speeds, while scansorial species will have relatively shorter limbs to keep the centre of mass closer to the substratum. Alternatively, terrestrial species in densely vegetated habitats could benefit from relatively shorter limbs to prevent entanglement with more frequently encountered obstacles, whereas scansorial species could benefit from longer limbs promoting greater limb spans and static stability. Cyrtodactylus, an ecologically diverse gekkonid genus, includes numerous specialists with narrow structural niches, but the degree of morphological diversification exhibited by these specialists is largely unknown. We investigated associations between locomotor morphology and structural microhabitat use in Cyrtodactylus to test if either of the opposing predictions can be corroborated for this radiation. We measured body length and relative limb dimensions of 87 species, covering multiple independent transitions among structural microhabitat preferences. Using these data, we reconstructed the phylomorphospace and tested for associations between structural microhabitat niche and limb morphology. We found strong separation between structural niche groups in accordance with the second hypothesis, although overlap is evident among functionally related niches such as those of granite and karst specialists.
    Wissenschaftlicher Artikel
    Band:51
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      51
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    Item-typ:Veröffentlichung,
    Sticky Innovation, Limited Expansion: Biogeography and Evolutionary Ecology of Toepads in Geckos
    (Wiley, 2025-10)
    Kukla, Yasemin
    ;
    Riedel, Jendrian
    ;
    Rödder, Dennis
    Wissenschaftlicher Artikel
    Band:52
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    Ecologically‐related variation of digit morphology in Cyrtodactylus (Gekkota, Squamata) reveals repeated origins of incipient adhesive toepads
    (British Ecological Society, 2024-07)
    Riedel, Jendrian
    ;
    Eisele, Katrin
    ;
    Gabelaia, Mariam
    ;
    Higham, Timothy
    ;
    Wu, Joseph
    Exploitation of different locomotor substrates in different ecological niches has driven the evolution of specialized morphological structures, and similar ecological demands, such as the structure of the microhabitat, often lead to convergent or parallel evolution. The evolution of adhesive toepads in geckos remains understudied because of the paucity of phylogenetically-informed investigations of candidate clades exhibiting purported incipient expression of these (i.e. species having evolved some, but not all, parts of the complex adhesive system of pad-bearing geckos). Using Cyrtodactylus, a speciose genus with well-established ecotypes, we tested the hypothesis that microhabitats that require more climbing will lead to the acquisition of incipient adhesive morphology. We measured subdigital scale area, a proxy for adhesive toepad evolution, and quantified subdigital scale shape for 77 of the 354 described species, including at least one representative of each ecotype. Subdigital scale area increased from terrestrial through generalist and saxicoline (rock-dwelling) to arboreal ecotypes, with subdigital scale shape evolving from ancestral conditions for padless lizards to lateromedially expanded lamella-like scales only in the arboreal ecotypes. This significant link between phenotype and environment supports the contention that scansorial, and particularly arboreal, Cyrtodactylus ecotypes have evolved incipiently expressed adhesive toepads. This highlights the suitability of this genus as a model system for studying the ecology and evolution of adhesive toepads as well as being a promising candidate for research on adaptive radiations.
    Wissenschaftlicher Artikel
    Band:38
    Heft:7
      50
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    Exploring Paleogene Tibet's warm temperate environments through target enrichment and phylogenetic niche modelling of Himalayan spiny frogs (Paini, Dicroglossidae)
    (Wiley, 2024-08)
    Hofmann, Sylvia
    ;
    Rödder, Dennis
    ;
    Andermann, Tobias
    ;
    Matschiner, Michael
    ;
    Riedel, Jendrian
    The Cenozoic topographic development of the Himalaya-Tibet orogen (HTO) substantially affected the paleoenvironment and biodiversity patterns of High Asia. However, concepts on the evolution and paleoenvironmental history of the HTO differ massively in timing, elevational increase and sequence of surface uplift of the different elements of the orogen. Using target enrichment of a large set of transcriptome-derived markers, ancestral range estimation and paleoclimatic niche modelling, we assess a recently proposed concept of a warm temperate paleo-Tibet in Asian spiny frogs of the tribe Paini and reconstruct their historical biogeography. That concept was previously developed in invertebrates. Because of their early evolutionary origin, low dispersal capacity, high degree of local endemism, and strict dependence on temperature and humidity, the cladogenesis of spiny frogs may echo the evolution of the HTO paleoenvironment. We show that diversification of main lineages occurred during the early to Mid-Miocene, while the evolution of alpine taxa started during the late Miocene/early Pliocene. Our distribution and niche modelling results indicate range shifts and niche stability that may explain the modern disjunct distributions of spiny frogs. They probably maintained their (sub)tropical or (warm)temperate preferences and moved out of the ancestral paleo-Tibetan area into the Himalaya as the climate shifted, as opposed to adapting in situ. Based on ancestral range estimation, we assume the existence of low-elevation, climatically suitable corridors across paleo-Tibet during the Miocene along the Kunlun, Qiangtang and/or Gangdese Shan. Our results contribute to a deeper understanding of the mechanisms and processes of faunal evolution in the HTO.
    Wissenschaftlicher Artikel
    Band:33
    Heft:15
      48