Aim: To infer the biogeographical and evolutionary history of the Western Mediterranean Psammodromus lizards with the aim of assessing the role of vicariance and dispersal on the cladogenetic events ...within the palaeogeological dynamics of the Strait of Gibraltar. Location: North Africa and Western Europe. Methods: We built a dataset including all six species of Psammodromus using mitochondrial (12S, cytb, nd4) and nuclear (acm4, mc1r, pomc) gene fragments. Species tree and concatenation methods were used to infer phylogenetic relationships and divergence times. Phylogenies were used for biogeographical inference using S-DIVA, DEC and BBM. Results: Psammodromus probably originated in Iberia, with P. algirus diverging early. The ancestor of the African P. blanci and P. microdactylus dispersed to Africa through the Betic-Rif massif, c. 10 Ma. The cladogenetic events within Africa and Iberia were probably due to vicariance mediated by habitat and climatic changes at the end of the Miocene (P. blanci and P. microdactylus) and during the Pliocene (P. occidentalis, P. hispanicus and P. edwardsianus). Psammodromus algirus shows three lineages, two in Iberia and one in Africa, the latter originated following a transmarine dispersal during the Middle Pleistocene (1.5 Ma). Main conclusions: Over-sea dispersal has played a major role in intercontinental exchange and divergence in Psammodromus, with two dispersal events towards Africa that occurred 10 and 1.5 Ma resulting in the African lineages. This study, combined with previous literature, provides compelling evidence that major biotic exchanges took place across the Strait of Gibraltar well before or long after the land connection during the Messinian Salinity Crisis (MSC, 5.9–5.33 Ma). These findings suggest caution in the application of the relatively short event of Atlantic flooding at the end of the MSC as cause for divergence in molecular clock calibrations, which is a popular approach in literature.
The identity of Scolelepis squamata (O.F. Müller,
1806
) (Spionidae) has long been under debate. For clarification of this problem a collection of Scolelepis specimens at the type locality of this ...species, the island of Helgoland (North Sea) and in particular the Helgoland Dunes, has been undertaken. Based on morphological and molecular studies the occurrence of only one Scolelepis species can be reported in the eulittoral zone. The specimens are in good accordance with the morphology of S. squamata. Based on these newly collected specimens S. squamata is redescribed and illustrated comprehensively, and, in addition, molecular information on several markers is provided. A neotype has been designated and deposited in the collection of the Zoological Museum at Hamburg University, Germany. Molecular phylogenetic analyses based on COI, 18S rRNA and 28S rRNA reveal little genetic diversity along the Atlantic coast from Helgoland to Portugal and thus support the occurrence of S. squamata in these coastal regions of the Eastern North Atlantic Ocean. Our results further indicate the presence of a distinct Scolelepis species in the Black Sea, which is closely related to S. squamata. Also, S. mesnili is reinstated as a valid species. Furthermore, it is shown that several earlier genetic studies had misidentified S. squamata specimens wrongly as S. foliosa or S. bonnieri, highlighting the need for the taxonomic redescription as well as for providing DNA barcodes from unambiguously identified specimens.
http://zoobank.org/urn:lsid:zoobank.org:pub:0D6C3783-FF06-4D84-8D92-B8691E88F0B9
Despite the diverse morphology of the adult squamate naso-palatal complex - consisting of the nasal cavity, vomeronasal organ (VNO), choanal groove, lacrimal duct and superficial palate - little is ...known about the embryology of these structures. Moreover, there are no comprehensive studies concerning development of the nasal cavity and VNO in relation to the superficial palate. In this investigation, we used X-ray microtomography and histological sections to describe embryonic development of the naso-palatal complex of iguanian lizard, the brown anole (
). The purpose of the study was to describe the mechanism of formation of adult morphology in this species, which combines the peculiar anole features with typical iguanian conditions. Considering the uncertain phylogenetic position of the Iguania within Squamata, embryological data and future comparative studies may shed new light on the evolution of this large squamate clade.
Development of the naso-palatal complex was divided into three phases: early, middle and late. In the early developmental phase, the vomeronasal pit originates from medial outpocketing of the nasal pit, when the facial prominences are weakly developed. In the middle developmental phase, the following events can be noted: the formation of the frontonasal mass, separation of the vestibulum, appearance of the lacrimal duct, and formation of the choanal groove, which leads to separation of the VNO from the nasal cavity. In late development, the nasal cavity and the VNO attain their adult morphology. The lacrimal duct establishes an extensive connection with the choanal groove, which eventually becomes largely separated from the oral cavity.
Unlike in other tetrapods, the primordium of the lacrimal duct in the brown anole develops largely beyond the nasolacrimal groove. In contrast to previous studies on squamates, the maxillary prominence is found to participate in the initial fusion with the frontonasal mass. Moreover, formation of the choanal groove occurs due to the fusion of the vomerine cushion to the subconchal fold, rather than to the choanal fold. The loss or significant reduction of the lateral nasal concha is secondary. Some features of anole adult morphology, such as the closure of the choanal groove, may constitute adaptations to vomeronasal chemoreception.
Reptiles, as well as other vertebrate groups, harbour a significant diversity of parasitic organisms, from nematodes and other helminths to viruses and bacteria. The Northeast is one of the richest ...regions in Brazil in terms of the reptile diversity, number of species and endemism. Parasites are diverse organisms and knowledge about the parasitic fauna of vertebrates is an important factor in understanding the ecological relationships between hosts and the environment. Studies on the parasitic fauna of reptiles in South America have increased in the past few years. The present review is a compilation of 122 studies published from 1924 to 2021. We present information on 101 species of reptiles from five groups (amphisbaenians, crocodile, testudines, snakes and lizards) and 183 parasitic taxa belonging to four phyla: Nematoda; Arthropoda; Platyhelminthes; and Acanthocephala. Nematodes were the most frequently recorded species. Lizards and snakes had more records of parasitism and higher levels of parasite richness and diversity. Ceará was the state with most studies and recorded cases of parasite-host association. The Caatinga and Atlantic Forest were the most investigated environments. The objective of this review was to contribute knowledge on the parasitic biodiversity in reptiles from Northeast Brazil, which may help identify gaps in our knowledge and guide future studies.
Christmas Island in the eastern Indian Ocean forms the pinnacle of a once-drowned, coral atoll. Exactly when the seamount re-emerged above the seas is, unfortunately, imprecisely understood. One of ...the consequences of this uncertainty is that it can hamper studies dealing with its land-locked faunal assemblage. We attempt to address this issue using geological and geophysical information. A first constraint is provided by sub-aerially erupted volcanic rocks that accumulated on a karstified land-surface. Radiometric ages for five associated basalt samples yield a mean of 4.39 ± 0.08 Ma (2σ). These data, together with the geological observations, indicate that the island existed in the mid-Early Pliocene. A second constraint is provided by the seamount's postulated uplift path as it ascended the outer-trench high on its journey towards the subduction zone south of Java. Here, the edifice is estimated to have become sub-aerial between 5.66 and 4.49 Ma (5.03 + 0.63/−0.54 Ma). In terms of biogeography, landmass emergence in the latest Miocene-Early Pliocene is largely concordant with the island's native land-locked reptile and mammal species (eight of the nine extant and recently extirpated forms are endemic) as most show only small to negligible levels of genetic differentiation with respect to their nearest off-island relatives. Significantly, though, molecular-clock data for at least two, possibly three, of the lizard species indicate that they split from their nearest living congeners (incidentally, all from lands to the east of the Wallace Line >1100 km away) prior to Christmas Island's emergence, that is in the Late Miocene or earlier (specifically at c. 7 Ma, c. 13 Ma and c. 26 Ma). Assuming the ages are reliable, these dichotomies could be explained if there are/were intermediate relatives that exist elsewhere/are now-extinct as this would facilitate the ancestors of the Christmas Island species colonizing the landmass sometime in the last five million years or so.
•Geological and geophysical data used to establish Christmas Island's re-emergence.•Volcanic rocks that were erupted sub-aerially 4.39 ± 0.08 Ma provide one constraint.•Up-warping paths derived from geophysical studies indicate exposure 5.66–4.49 Ma.•Data will be important for biogeographical interpretations of the island's biota.
Assisted reproductive technologies such as cooling, freezing, and artificial insemination are essential in conserving genetic diversity of critically endangered reptiles like the golden lancehead ...pitviper (Bothrops insularis). Therefore, we examined viability of semen samples from captive golden lanceheads diluted in coconut‐water based extender over a 48‐h period of cooling (5°C). Semen evaluations were performed immediately after the dilution and at 6, 24, and 48 h, using computer‐assisted sperm analysis and stains to assess plasma membrane and acrosomal status. Our findings showed that the extender and protocol employed here were effective in preserving golden lancehead pitviper spermatozoa for a short periods of time (48 h), allowing semen samples to be transported to distant locations for immediate use without the setbacks of cryopreservation.
The critically endangered golden lancehead pitviper (Bothrops insularis) semen collection and preservation in coconut‐water based extender will enables the exchange of genetic material between ex situ and in situ populations.
Research Highlights
The results of plasma membrane and acrosome integrity for Bothrops insularis demonstrates that is possible to maintain sperm membrane viability in ACP‐120 medium for up to 48 h.
The resistance of spermatozoon to short‐term and indeed long‐term storage may allow the exchange of genetic material between wild and captive animals.
The semen samples diluted in ACP‐120 and stored under refrigeration for up to 48 h were considered viable for use in artificial insemination.
Within-species colour variation is widespread among animals. Understanding how this arises can elucidate evolutionary mechanisms, such as those underlying reproductive isolation and speciation. Here, ...we investigated whether five island populations of Aegean wall lizards (Podarcis erhardii) have more effective camouflage against their own (local) island substrates than against other (non-local) island substrates to avian predators, and whether this was linked to island differences in substrate appearance. We also investigated whether degree of local substrate matching varied among island populations and between sexes. In most populations, both sexes were better matched against local backgrounds than against non-local backgrounds, particularly in terms of luminance (perceived lightness), which usually occurred when local and non-local backgrounds were different in appearance. This was found even between island populations that historically had a land connection and in populations that have been isolated relatively recently, suggesting that isolation in these distinct island environments has been sufficient to cause enhanced local background matching, sometimes on a rapid evolutionary time-scale. However, heightened local matching was poorer in populations inhabiting more variable and unstable environments with a prolonged history of volcanic activity. Overall, these results show that lizard coloration is tuned to provide camouflage in local environments, either due to genetic adaptation or changes during development. Yet, the occurrence and extent of selection for local matching may depend on specific conditions associated with local ecology and biogeographic history. These results emphasize how anti-predator adaptations to different environments can drive divergence within a species, which may contribute to reproductive isolation among populations and lead to ecological speciation.
Most reptiles are oviparous (egg-laying), but viviparity (live-bearing) has evolved about 100 times in lizards and snakes. Geographic biases in the distribution of viviparous species stimulated the ...“cold-climate hypothesis,” proposed independently by three field-based researchers in the early 1900s. Mell (in China) and Weekes (in Australia) viewed viviparity as a mechanism for thermal buffering of embryos from nighttime frosts, whereas Sergeev (in Russia) suggested that eggs retained in utero would develop faster because they were kept warmer, enabling early hatching. Although alternative adaptationist hypotheses proliferated over the next few decades, many had logical flaws (failing to consider intermediate stages). Phylogenetically based analyses identified around 100 independent origins of viviparity from oviparity, and revealed a strong trend for viviparity to evolve in cold climates. After experimental studies showed that incubation temperatures affect offspring phenotypes as well as rates of development and survival, I proposed (in 1995) that by retaining eggs in utero, a mother can manipulate the phenotypic traits of her offspring (and thus, enhance their fitness). This mother of all hypotheses subsumes the cold-climate hypothesis, and has been supported by studies on both oviparous and viviparous squamates, and in tropical as well as cold-climate areas. The history of this research topic illustrates the emergence of similar ideas from different researchers (sometimes creating tensions); the major roles of happenstance and field experience in suggesting ideas and allowing them to be tested; and the vital contributions of concepts, methodologies, and technologies from other fields to our understanding of reptilian viviparity.
Non-ophidian ophidiomorphs, colloquially referred to as ‘dolichosaurs,’ are small-bodied aquatic lizards that lived in shallow seaways, rivers, and reef environments during the Late Cretaceous. ...Preservational, geographic, and taphonomic biases in this group make trends in biodiversity difficult to assess. This is exemplified by the fact that the majority of the described species are monotypic and known only from single specimens, imparting very little information on morphological or spatial variation. Here we present a revision of the spatial and temporal distributions of non-ophidian ophidiomorph lizards (‘dolichosaurs’) from Cretaceous sediments worldwide. The fossil record of dolichosaurs begins in the Valanginian (Early Cretaceous). The late Early Cretaceous records are sparse but suggest a wide geographic distribution spanning the Tethys and Western Pacific. This is followed by a dense Cenomanian record from Tethyan and British deposits, and rarer specimens from North America. Though there is a substantial drop in the number of specimens recorded from the Turonian–Maastrichtian, these rare occurrences represent the largest geographical distribution of dolichosaurs: spanning Europe, North America, and South America before going extinct during the end-Cretaceous mass extinction. These occurrences indicate that ophidiomorphs most likely originated in the Jurassic Tethys and continued to radiate spatially and phylogenetically until the end of the Mesozoic, showing much more temporally and environmentally diverse patterns than previously indicated.
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