Subjects -> PALEONTOLOGY (Total: 43 journals)
Showing 1 - 21 of 21 Journals sorted alphabetically
Alcheringa: An Australasian Journal of Palaeontology     Hybrid Journal   (Followers: 6)
Ameghiniana     Open Access  
Annales de Paléontologie     Full-text available via subscription   (Followers: 4)
Annals of Carnegie Museum     Full-text available via subscription   (Followers: 1)
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 13)
Comptes Rendus Palevol     Open Access  
European Journal of Protistology     Hybrid Journal   (Followers: 5)
EvoDevo     Open Access   (Followers: 4)
Facies     Hybrid Journal   (Followers: 9)
Fossil Record     Open Access   (Followers: 5)
Geobios     Full-text available via subscription   (Followers: 4)
Geologica Saxonica     Open Access   (Followers: 2)
Historical Biology: An International Journal of Paleobiology     Hybrid Journal   (Followers: 9)
Ichnos: An International Journal for Plant and Animal Traces     Hybrid Journal  
International Journal of Speleology     Open Access   (Followers: 3)
Journal of Paleolimnology     Hybrid Journal   (Followers: 5)
Journal of Paleontology     Hybrid Journal   (Followers: 8)
Journal of Quaternary Science     Hybrid Journal   (Followers: 31)
Journal of Vertebrate Paleontology     Full-text available via subscription   (Followers: 8)
Marine Micropaleontology     Hybrid Journal   (Followers: 2)
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen     Full-text available via subscription   (Followers: 3)
Novitates Paleoentomologicae     Open Access   (Followers: 1)
Open Quaternary     Open Access  
Palaeogeography, Palaeoclimatology, Palaeoecology     Hybrid Journal   (Followers: 13)
Palaeontographica A     Full-text available via subscription   (Followers: 3)
Palaeontology     Hybrid Journal   (Followers: 17)
Palaeoworld     Hybrid Journal   (Followers: 3)
Paläontologische Zeitschrift     Hybrid Journal   (Followers: 4)
Paleobiology     Full-text available via subscription   (Followers: 6)
PaleoBios     Open Access   (Followers: 1)
Paleoceanography and Paleoclimatology     Full-text available via subscription   (Followers: 5)
Paleontological Journal     Full-text available via subscription   (Followers: 4)
Palynology     Hybrid Journal   (Followers: 1)
Papers in Palaeontology     Hybrid Journal  
Peer Community Journal     Open Access   (Followers: 4)
Quaternaire     Open Access   (Followers: 3)
Quaternary Research     Full-text available via subscription   (Followers: 19)
Quaternary Science Reviews     Hybrid Journal   (Followers: 26)
Review of Palaeobotany and Palynology     Hybrid Journal   (Followers: 1)
Revue de Micropaleontologie     Full-text available via subscription  
Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy)     Open Access   (Followers: 1)
Spanish Journal of Palaeontology     Open Access  
Swiss Journal of Palaeontology     Hybrid Journal   (Followers: 4)
Vertebrate Anatomy Morphology Palaeontology     Open Access   (Followers: 1)
Zitteliana     Open Access  
Similar Journals
Journal Cover
Swiss Journal of Palaeontology
Journal Prestige (SJR): 0.396
Citation Impact (citeScore): 1
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1664-2376 - ISSN (Online) 1664-2384
Published by Springer-Verlag Homepage  [2469 journals]
  • Morphological disparity in extant and extinct sepiid phragmocones:
           morphological adaptions for phragmocone strength compared to those related
           to cameral liquid emptying hypotheses

    • Free pre-print version: Loading...

      Abstract: Abstract The phragmocone-bearing coleoid cephalopods Sepia, Sepiella, Metasepia and Hemisepius (sepiids) are the most diverse of all extant chambered cephalopods and show the highest disparity. As such, they have a great potential to serve as model organisms to better understand the paleobiology not only of extinct coleoids, but of extinct nautiloids and ammonoids as well. Here, we present new measurements from the phragmocones of Sepia and Sepiella and relate these to known maximum depths. While these latter data remain few for some species, in aggregate they provide progress allowing this work. In so doing, we expand upon the great legacy of Sigurd von Boletzky. We show that deep water-inhabiting sepiids have phragmocones with a higher number of septa per length, a smaller area covered by the last chamber in relation to the volume of all previous phragmocone chambers, are smaller in size (length and volume), and bear dorsal shields that have strengthening central rib(s) compared to most species from shallower water; the very small endemic species of South Africa may be an exception. We show that the various subgenera defined by Khromov (1987) are not monophyletic clades but morphological groupings explicitly related to depth, partially evolved convergently. We conclude with analyses of Australian sepiid assemblages and show that these are depth related in ways analogous to ammonite and/or nautiloid assemblages of the past that are later commingled through post-mortal drift.
      PubDate: 2022-05-03
       
  • Relationships of growth increments of internal shells and age through
           entire life cycles in three cultured neritic cephalopods (Mollusca:
           Cephalopoda) with re-evaluation as application for age determination

    • Free pre-print version: Loading...

      Abstract: Abstract Relationships between growth increments of internal shell and age was studied in three neritic decapod cephalopods cultured in laboratory through their entire life cycles. The studied cephalopods were the nektic Sepioteuthis lessoniana d’Orbigny, 1826, Sepia pharaonis Ehrenberg, 1831 and Sepiella inermis Van Hasselt, 1835. Most of the relationship models are in cubic parabolic, except when numbers of increments were estimated from age in S. pharaonis. Differences of numbers of increments from the real age were higher in the pelagic S. lessoniana when compared to the benthic sepiids. The differences were higher in juvenile stages (< 60 days after hatching) than adult stages (> 60 days) in the three species. The increment rate is close to the “one day one increment” assumption. The differences of numbers of increments from the ages and the rate of increment apposition revealed the transition point of the life cycle from 60 days of age, corresponding to the sexual maturity or adult stages. Numbers of increments with higher accuracy are reevaluated to be reliable for age determination at least for the neritic species in the tropical zone, where environmental conditions are more stable, regarding the life styles and stages in life cycles of each species.
      PubDate: 2022-04-18
       
  • Is the relative thickness of ammonoid septa influenced by ocean
           acidification, phylogenetic relationships and palaeogeographic
           position'

    • Free pre-print version: Loading...

      Abstract: Abstract The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the focus of current environmental research. These factors cause problems for marine calcifiers such as reduced calcification rates and the dissolution of calcareous skeletons. While the impact on recent organisms is well established, little is known about long-term evolutionary consequences. Here, we assessed whether ammonoids reacted to environmental change by changing septal thickness. We measured the septal thickness of ammonoid phragmocones through ontogeny in order to test the hypothesis that atmospheric pCO2, seawater pH and other factors affected aragonite biomineralisation in ammonoids. Particularly, we studied septal thickness of ammonoids before and after the ocean acidification event in the latest Triassic until the Early Cretaceous. Early Jurassic ammonoid lineages had thinner septa relative to diameter than their Late Triassic relatives, which we tentatively interpret as consequence of a positive selection for reduced shell material as an evolutionary response to this ocean acidification event. This response was preserved within several lineages among the Early Jurassic descendants of these ammonoids. By contrast, we did not find a significant correlation between septal thickness and long-term atmospheric pCO2 or seawater pH, but we discovered a correlation with palaeolatitude.
      PubDate: 2022-04-18
       
  • Scleractinian corals from the Lower Cretaceous of the Alpstein area
           (Anthozoa; Vitznau Marl; lower Valanginian) and a preliminary comparison
           with contemporaneous coral assemblages

    • Free pre-print version: Loading...

      Abstract: Abstract From the Vitznau Marl (lower Valanginian) at the locality Wart in northeastern Switzerland (Alpstein area), 18 species from 17 genera and 13 families are described, including the genera Actinaraea, Actinastrea, Adelocoenia, Aplosmilia, Axosmilia, Complexastrea, Cyathophora, Dermosmilia, Fungiastraea, Heterocoenia, Latiastrea, Montlivaltia, Placophyllia, Pleurophyllia, Stylophyllopsis, Thamnoseris, and specimens showing affinities to solitary stylophyllids. The corals from the Vitznau Marl were derived from a limestone–marl alternation that is fossiliferous and clay-rich at the base (Vitznau Marl), containing crinoids, bryozoans, and sparse reworked corals and sponges. The coral fauna is distinctly dominated by forms belonging to the category of lowest to no polyp integration (50%), followed by species of the cerioid-plocoid group (33%) and forms having the highest polyp integration (thamnasterioid; 17%). With regard to polypar size, the Wart fauna is dominated by corals having large-size (> 9 mm) polyps (= 39%), followed by corals having medium- (> 2.5‒9 mm; 33%) and small-size polyps (up to 2.5 mm; 28%). Based on morphological features, the fauna from the Vitznau Marl closely corresponds to coral assemblages that are subjected to near-chronic, moderate sediment-turbidity stress that is punctuated by high-stress events, and that are largely or entirely heterotrophic. No coral fabric was observed that would suggest a biohermal development. But in a very small number of places, structures are present which might be fragments of crusts of microbialites, pointing to the hypothesis that at least a few of the corals might have been a part of some kind of bioconstruction. At the species-level, the fauna of the Vitznau Marl shows either no or very little affinities to other Valanginian assemblages such as to the fauna of Hungary (4.3%), followed by the associations of Ukraine, Switzerland (non-Vitznau), Spain (SpII), and Bulgaria. At the genus-level, the Wart fauna shows low correspondence to the fauna of Spain (SpII) (14.5%), followed by the assemblages of Hungary, Bulgaria, and Ukraine. In addition to the Vitznau Marl corals, an account of all Valanginian coral faunas published before early 2021 is given, including their paleogeographic distribution, as well as their taxonomic and morphological characterization. For this preliminary study, a total of 206 coral species belonging to 97 genera found in the coral assemblages of the Valanginian were included. At both the genus- and the species-levels, colonial taxa are most abundant (colonial genera: 89%; colonial species 90%). The vast majority of the Valanginian genera already occurred in older strata. Only 11 genera (out of 97 = 11%) are newly recorded. The Valanginian faunas having the largest number of solitary taxa lived in both (sub-) paratropical to warm-temperate areas, and in arid regions. The coral faunas of the Valanginian are distinctly dominated by corals of well-established microstructural groups. Only 13% of the species from 24% of the genera belong to “modern” groups. Compared to the situation in the Berriasian which showed that 9% of the species and 17% of the genera belonged to modern microstructural groups, the occurrence of “modern” groups significantly increased during the Valanginian.
      PubDate: 2022-03-12
       
  • Fish otoliths from the middle Miocene Pebas Formation of the Peruvian
           Amazon

    • Free pre-print version: Loading...

      Abstract: Abstract A small assemblage of 22 otoliths was identified from the historical collection of Bluntschli and Peyer gathered in 1912 on the Itaya riverbank at Iquitos, Peru (Amazonia), from the Pebas Formation. The Pebas Mega-Wetland System in western Amazonia during the Miocene represented a unique, albeit short-lived, biotope characterized by a pronounced endemic evolution with gigantism in some vertebrate groups (e.g., turtles, crocodylians). Thus far, fishes have mainly been recorded based on isolated skeletal remains and teeth. Here, we describe the first well-preserved otolith assemblage from the Pebas Formation. This otolith assemblage adds a new facet to the fauna by complementing the skeletal bony fish data, primarily with species of the Sciaenidae and, to a lesser extent, Ariidae and Cichlidae. The sciaenids and ariids indicate that migration must have occurred between the marginal marine environments to the north and the Pebas Wetland System. The otoliths also indicate the likelihood of endemic developments of adapted marine immigrants to the Pebas Wetland System, some of which have become extinct (Pogonias, Umbrina), while others now represent typical South American freshwater fish groups (Plagioscion). Six new species are described based on otoliths, one in the Cichlidae—Cichlasoma bluntschlii n. sp., one in the Ariidae—Cantarius ohei n. sp., and four in the Sciaenidae—Pebasciaena amazoniensis n. gen. et n. sp., Plagioscion peyeri n. sp., Pogonias tetragonus n. sp. and Umbrina pachaula n. sp.
      PubDate: 2022-02-24
      DOI: 10.1186/s13358-022-00243-5
       
  • A large osteoderm-bearing rib from the Upper Triassic Kössen Formation
           (Norian/Rhaetian) of eastern Switzerland

    • Free pre-print version: Loading...

      Abstract: Abstract An important component of the Alpine vertebrate record of Late Triassic age derives from the Kössen Formation, which crops out extensively in the eastern Alps. Here, we present an isolated and only partially preserved large rib, which carries an osteoderm on a low uncinate process. Osteological comparison indicates that the specimen likely belongs to a small clade of marine reptiles, Saurosphargidae. Members of the clade are restricted to the western (today Europe) and eastern margins of the Tethys (today China) and were so far known only from the Anisian stage of the Middle Triassic. The assignment of the new find to cf. Saurosphargidae, with potential affinities to the genus Largocephalosaurus from the Guanling Formation of Yunnan and Guizhou Provinces, China, would extend the occurrence of the clade about 35 million years into the Late Triassic.
      PubDate: 2022-02-23
      DOI: 10.1186/s13358-022-00244-4
       
  • A historical vertebrate collection from the Middle Miocene of the Peruvian
           Amazon

    • Free pre-print version: Loading...

      Abstract: Abstract The Miocene aquatic and terrestrial fossil record from western Amazonia constitute a clear evidence of the palaeoenvironmental diversity that prevailed in the area, prior to the establishment of the Amazon River drainage. During the Miocene, the region was characterized by a freshwater megawetland basin, influenced by episodic shallow-marine incursions. A fossil vertebrate collection from the middle Miocene strata of the Pebas Formation is here studied and described. This historical collection was recovered in 1912 along the banks of the Itaya River (Iquitos, Peru), during a scientific expedition led by two scientists of the University of Zurich, Hans Bluntschli and Bernhard Peyer. Our findings include a total of 34 taxa, including stingrays, bony fishes, turtles, snakes, crocodylians, and lizards. Fishes are the most abundant group in the assemblage (~ 23 taxa), including the first fossil record of the freshwater serrasalmids Serrasalmus, and Mylossoma, and the hemiodontid Hemiodus for the Pebas system, with the latter representing the first fossil be discovered for the entire Hemiodontidae. The presence of a representative of Colubroidea in the middle Miocene of Iquitos supports the hypothesis of arrival and dispersal of these snakes into South America earlier than previously expected. This fossil assemblage sheds light on the palaeoenvironments, and the geographical/temporal range of several aquatic/terrestrial lineages inhabiting the Amazonian region.
      PubDate: 2021-12-20
      DOI: 10.1186/s13358-021-00239-7
       
  • Evolutionary development of the cephalopod arm armature: a review

    • Free pre-print version: Loading...

      Abstract: Abstract The cephalopod arm armature is certainly one of the most important morphological innovations responsible for the evolutionary success of the Cephalopoda. New palaeontological discoveries in the recent past afford to review and reassess origin and homology of suckers, sucker rings, hooks, and cirri. Since a priori character state reconstructions are still ambiguous, we suggest and discuss three different evolutionary scenarios. Each of them is based on the following assumptions: (1) Neocoleoidea uniting extant Decabrachia and Octobrachia is monophyletic (= proostracum-bearing coleoids); (2) extinct Belemnitida and Diplobelida are stem decabrachians; (3) proostracum-less coleoids (Hematitida, Donovaniconida, Aulacoceratida) represent stem-neocoleoids; (4) Ammonoidea and Bactritoidea are stem coleoids. We consider a scenario where belemnoid hooks derived from primitive suckers as well-supported. Regarding belemnoid hooks and suckers as homologues implies that belemnoid, oegopsid, and probably ammonoid arm hooks arose through parallel evolution. Our conclusions challenge the widespread opinion, whereupon belemnoid hooks evolved de novo, and instead support earlier ideas formulated by Sigurd von Boletzky.
      PubDate: 2021-12-20
      DOI: 10.1186/s13358-021-00241-z
       
  • The impact of the Pliensbachian–Toarcian crisis on belemnite
           assemblages and size distribution

    • Free pre-print version: Loading...

      Abstract: Abstract The second-order Pliensbachian–Toarcian crisis affected major groups of marine organisms. While its impact has been intensively studied for ammonites, the response of belemnites is only currently emerging through quantitative studies. Novel overall and regional diversity analyses suggest that belemnite richness in the NW-Tethys drops at the Pliensbachian–Toarcian boundary, while overall diversity slightly increases in NW-Tethys assemblages during the Toarcian Oceanic Anoxic event (T-OAE), mostly driven by NW European assemblages (e.g., Yorkshire). The T-OAE coincides with marked taxonomic turnover within individual basins, which is associated with an increase in median rostrum size of specimens in taxa at most localities. The changes in median body size across the Pliensbachian–Toarcian boundary are less consistent and driven by changes in body size within individual lineages crossing the boundary. However, our analyses also illustrate differences in sampling across the Pliensbachian–Toarcian crisis, which needs to be considered in further studies.
      PubDate: 2021-12-20
      DOI: 10.1186/s13358-021-00242-y
       
  • Novel insights into early life stages of finned octopods (Octopoda:
           Cirrata)

    • Free pre-print version: Loading...

      Abstract: Abstract The finned or dumbo octopods (Octopoda: Cirrata) constitute a cephalopod (Mollusca: Cephalopoda) taxon almost exclusively comprising organisms that inhabit the deep-sea. This renders studying the general biology of adult cirrate specimens a difficult task, but even more so when it comes to gathering knowledge on their early life stages. During his comprehensive research exploits on cephalopod development, the late Sigurd von Boletzky (1942–2020) also sought to shed light on specific adaptations that eggs and embryos of these enigmatic deep-sea octopods might show. Based on his seminal work, the present article sets out to provide additional data on a broad range of early cirrate life stages, including egg capsules without any obvious embryonic stage as well as those containing embryos. These previously unreported specimens obtained from museum collections were analyzed using conventional morphological as well as modern three-dimensional imaging techniques. The present overview includes specimens from four of the five oceans, i.e., the Atlantic, Pacific, Indian, and Southern Ocean. Based on information on cirrate ovum, chorion, and egg capsule size as well as shape gathered from the literature, an attempt is made here for the first time to identify von Boletzky's as well as the specimens introduced here down to at least genus level. The combined data provide novel insights into early life stages of finned octopods, aiming to continue von Boletzky's legacy with regard to developmental research on a still largely enigmatic taxon of extant deep-sea cephalopods.
      PubDate: 2021-12-20
      DOI: 10.1186/s13358-021-00240-0
       
  • A redescription of the Late Jurassic (Tithonian) turtle Uluops uluops and
           a new phylogenetic hypothesis of Paracryptodira

    • Free pre-print version: Loading...

      Abstract: Abstract We study the Late Jurassic (Tithonian) turtle Uluops uluops using micro-computed tomography scans to investigate the cranial anatomy of paracryptodires, and provide new insights into the evolution of the internal carotid artery and facial nerve systems, as well as the phylogenetic relationships of this group. We demonstrate the presence of a canalis caroticus lateralis in Uluops uluops, the only pleurosternid for which a palatine artery canal can be confidently identified. Our phylogenetic analysis retrieves Uluops uluops as the earliest branching pleurosternid, Helochelydridae within Pleurosternidae, and Compsemydidae including Kallokibotion bajazidi within Baenidae, which suggests at least two independent losses of the palatine artery within paracryptodires. We expect future studies will provide additional insights into the evolution of the circulation system of paracryptodires, as well as clarifying relationships along the turtle stem.
      PubDate: 2021-10-06
      DOI: 10.1186/s13358-021-00234-y
       
  • Observations on mating in Mediterranean Sepiola and Sepietta species and
           review of mating behaviour in Sepiolinae (Cephalopoda: Sepiolidae)

    • Free pre-print version: Loading...

      Abstract: Abstract Mating was observed and described in captive individuals of Sepiola affinis, Sepiola intermedia and Sepietta obscura (Cephalopoda: Sepiolidae) collected in the Catalan Sea, western Mediterranean Sea. This is the first report of a mating event in S. intermedia; it is also the first detailed description of the mating behaviour for the other two species. The published literature on mating in Sepiolinae, which includes both cursory reports and in-depth descriptions of mating events, was thoroughly reviewed. In all, copulation has been examined in eight species belonging to four different genera, namely, Eumandya, Euprymna, Sepietta and Sepiola, starting from 1894 to the present. Common traits of the mating behaviour were detected among the studied sepioline species, so that a general five stages succession of actions is established to portray the mating progress in Sepiolinae: (A) female hovers by, male attention (it is discussed whether actual copulation is preceded by any courtship); (B) male approaches female from below; (C) male grasps female at the neck by its third arms, inserts its first arms in the female’s mantle cavity (the hectocotylised left arm is thus aligned with the bursa copulatrix), holds the female’s mantle by its second arms and positions itself and mate in the “parallel position”; (D) copulation and transfer of spermatophores from male to female (this stage may last from 3 min to 3 h); (E) mating dissolution. Mating occurs preferentially during the dark hours; it is described as violent and the female tries to escape the forceful grasp by the male; the male skin coloration turns darker. The similarity of the mating behaviour in all examined sepioline species is an evidence of both its evolution in harmony with their copulatory organs (hectocotylus and bursa copulatrix) and, seemingly, its common derivation to the whole Sepiolinae clade.
      PubDate: 2021-10-05
      DOI: 10.1186/s13358-021-00232-0
       
  • Analysis of septal spacing and septal crowding in Devonian and
           Carboniferous ammonoids

    • Free pre-print version: Loading...

      Abstract: Abstract Septal crowding is widely known as a sign of maturity in conchs of ammonoids and nautiloids. However, reduced septal spacing may also occur as a consequence of adverse ecological conditions. Here, we address the question how septal spacing varied through ontogeny in representatives of some of the major clades of Devonian and Carboniferous ammonoids. We found that the degree of ontogenetic variation is similar between clades and that variation is only weakly linked with conch form. The results show that septal crowding alone is insufficient to identify adulthood in ammonoids; intermediate septal crowding is a common phenomenon and occurs in various growth stages. Changes in septal distances during ontogeny were, in addition to adulthood of the individuals, a passive reaction likely caused by fluctuating environmental conditions.
      PubDate: 2021-10-04
      DOI: 10.1186/s13358-021-00235-x
       
  • An assemblage of giant aquatic snakes (Serpentes, Palaeophiidae) from the
           Eocene of Togo

    • Free pre-print version: Loading...

      Abstract: Abstract We here describe a monospecific assemblage of giant aquatic snakes from the middle Eocene of Kpogamé, Togo. The material, consisting of large isolated vertebrae, is referred to Palaeophis africanus, an enigmatic palaeophiid species, which was so far otherwise known only from a limited number of vertebrae from the middle Eocene of Nigeria and Angola. Material from the late Eocene of the eastern USA that had been referred to the same species, is here instead considered too fragmentary for species-level determination and Palaeophis africanus is thus so far restricted to Africa. With the aid of micro-CT scanning, we present 3D models of 17 vertebrae, pertaining to different portions of the vertebral column. We provide detailed comparisons of the new material with all named African species of the genus Palaeophis. A tentative diagnosis of Palaeophis africanus is provided. With more than 50 vertebrae, the new Togolese specimens represent the most abundant known material attributed to Palaeophis africanus and significantly enhance our knowledge of the vertebral anatomy and intracolumnar variation for this taxon. Furthermore, this adds to the, as yet, extremely scarce fossil record of squamates from central western Africa, a region where Paleogene herpetofaunas are only rather poorly known.
      PubDate: 2021-09-23
      DOI: 10.1186/s13358-021-00236-w
       
  • The swimming trace Undichna from the latest Devonian Hangenberg Sandstone
           equivalent of Morocco

    • Free pre-print version: Loading...

      Abstract: Abstract Trace fossils occur in several strata of the Devonian and Carboniferous of the eastern Anti-Atlas, but they are still poorly documented. Here, we describe a fossil swimming trace from strata overlying the Hangenberg Black Shale (correlation largely based on lithostratigraphy; Postclymenia ammonoid genozone, ca. 370 Ma old). We discuss the systematic position of the tracemaker and its body size. This ichnofossil is important for three main reasons: (1) it is considered here to be the first record of Undichna from the Devonian of Gondwana, as far as we know; (2) it is the oldest record of vertebrate trace fossils from Africa; (3) it provides a unique window into the behaviour of Late Devonian fishes for which body-fossils cannot provide direct evidence. Further, we put this discovery into the macroecological context of the palaeoenvironment following the Late Devonian Hangenberg biodiversity crisis.
      PubDate: 2021-09-13
      DOI: 10.1186/s13358-021-00237-9
       
  • Taxonomic revision of the snakes of the genera Palaeopython and Paleryx
           (Serpentes, Constrictores) from the Paleogene of Europe

    • Free pre-print version: Loading...

      Abstract: Abstract Large constrictor snakes, referred to the genera Palaeopython and Paleryx, are an ecologically prominent part of the fauna of Europe during the Paleogene. Most species were named over a century ago and their taxonomy is largely based on isolated vertebrae. Furthermore, the majority of named taxa originate from imprecisely known localities within the Phosphorites du Quercy, in southern France, and thus their exact age is not known. We critically review and re-diagnose these genera based on personal examination of all existing type material, an array of new specimens, and a detailed literature review. We consider Palaeopython and Paleryx to be valid and propose vertebral characters to distinguish them. We recognize three valid species of Palaeopython, i.e. Palaeopython cadurcensis (type species) from the Phosphorites du Quercy, Palaeopython ceciliensis from Geiseltal, and Palaeopython helveticus from Dielsdorf (Switzerland), and one valid species of Paleryx, i.e. Paleryx rhombifer (type species) from Hordle Cliff (England). Four other species, which were previously treated as members of Palaeopython and Paleryx, i.e. “Palaeopython” filholii and “Palaeopython” neglectus from the Phosphorites du Quercy, “Palaeopython” fischeri from Messel, and “Paleryx” spinifer from Geiseltal, are also considered as valid but pertain to other genera. Among these four taxa, “Palaeopython” fischeri has been recently assigned to its own genus, Eoconstrictor. A new genus, Phosphoroboa gen. nov. is established to accommodate “Palaeopython” filholii. We designate a lectotype for Palaeopython cadurcensis and establish that the paralectotype maxilla and dentary are reasonably referred to this species. New material attributed to Palaeopython cadurcensis is described from the old collections of the Phosphorites du Quercy. Paleryx cayluxi, another species established from the old collections of the Phosphorites du Quercy, is synonymized here with Palaeopython cadurcensis. We further clarify important errors in the original description and figures of Paleryx cayluxi, identify the exact specimens that comprise the type series, and designate a lectotype. Much new material is described for Palaeopython ceciliensis from its type area in Geiseltal and intracolumnar variation is considered. We describe additional vertebral and cranial material of Paleryx rhombifer from its type area in Hordle Cliff. Based on this cranial material, we suggest non-booid affinities for Paleryx rhombifer. We designate a lectotype for Paleryx depressus and agree with its previous suggested synonymy with Paleryx rhombifer. We re-describe the lectotype and paralectotypes of “Palaeopython” neglectus and refer and describe new material of this species from the Phosphorites du Quercy, paying special attention to intracolumnar variation; we also defer a decision on its generic relations until more abundant and complete material can be studied. We describe new vertebral material of the booid Eoconstrictor cf. fischeri from Geiseltal; similar material was previously known only from Messel and Dielsdorf. We determine that Eoconstrictor fischeri contains two distinct and unrelated species and describe intracolumnar variation in the nominotype. We clarify certain issues regarding the type series of Paleryx spinifer, designate a lectotype, and report previously unrecognized cranial material associated with the latter specimen; we transfer this species to Eoconstrictor based on cranial features and recombine it as Eoconstrictor spinifer comb. nov. We finally describe much new vertebral and cranial material of Phosphoroboa filholii comb. nov. from the Phosphorites du Quercy (both from the old collections but also from the late Eocene localities of Escamps A and C), paying special attention to intracolumnar variation. Based on this cranial material from Escamps, we identify Phosphoroboa gen. nov. as a booid. An analytical approach is undertaken in many isolated remains in order to quantify v...
      PubDate: 2021-08-13
      DOI: 10.1186/s13358-021-00224-0
       
  • The geography of body size in cuttlefishes (Cephalopoda, Sepiidae)

    • Free pre-print version: Loading...

      Abstract: Abstract This study explores body size in sepiids (Cephalopoda, Sepiidae) on the interspecific scale and provides an overview of their geographical distribution. Results reveal a highly skewed distribution of body size variation for raw values and a nearly normal distribution for log-transformed data. However, normality is not statistically validated due to the overrepresentation of small and large species. The geographical distribution of sepiids reveals five main clusters: Atlantic, Cape Basin, Indian Ocean, Asia-Pacific, and Australian. On average, clusters display more or less the same mean body size pattern except the Cape Basin cluster, which is statistically different from the others (smaller interspecific mean body size). The reasons remain unclear but a phylogenetic effect is suspected as southwest African coastal waters concentrate species from the ‘Hemisepius’ complex which is made up of small species. Sepiids do not obey Bergmann’s rule: species from high latitudes do not tend to be larger than species from low latitudes.
      PubDate: 2021-07-28
      DOI: 10.1186/s13358-021-00231-1
       
  • Fish otoliths from the early Miocene of Chile: a window into the evolution
           of marine bony fishes in the Southeast Pacific

    • Free pre-print version: Loading...

      Abstract: Abstract Few fossil fish otolith associations have been described from the Pacific side of the Americas and, except for a single species (Steindachneria svennielseni), none have been described from Pacific South America south of the Central American tropical region. Here, we describe a rich otolith assemblage obtained from fifteen early Miocene outcrop locations along the Chilean coast from about 33°S to about 45°S. More than 2,000 specimens were studied resulting in the recognition of 67 species, with 27 being new to science. This assemblage represents an important new data point distant from any previously known otolith-based fish fauna, with the nearest coeval associations being from the Caribbean Province in Venezuela, which lies about 5000 km to the north, and New Zealand, which is about 9000 km to the west. The fauna represents a mixture of offshore and shallow water fishes and is rich in myctophids, paralichthyids (Citharichthys), ophidiids (Lepophidium), steindachneriids, and macrourids. Typical tropical American fishes are nearly completely absent, with the exception of Steindachneria and certain anguilliforms. The mesopelagic faunal component, chiefly Myctophidae, shows a striking resemblance to the well-known coeval fish fauna from New Zealand, and both are interpreted as representing an early South Pacific mesopelagic bioprovince. The strong correlation with the mesopelagic otolith-based fish fauna from New Zealand constricts the time interval of the sampled sediments to the middle Burdigalian (approximately 17.5 to 18.5 Ma). All otoliths obtained from the early Miocene of Chile relate to extant fish groups of the area and few exotic components not currently present in the East Pacific. The sole exception is a morpho-type described as Navidadichthys which has an unresolved relationship, possibly with the Prototroctidae, a family that is today endemic to the freshwater and nearshore marine environments of Australia and New Zealand. The new taxa are in the sequence of taxonomic description: Pterothrissus transpacificus n. sp., Pythonichthys panulus n. sp., Chiloconger chilensis n. sp., Gnathophis quinzoi n.sp., Rhynchoconger chiloensis n. sp., Navidadichthys mirus n. gen. et n. sp., Maurolicus brevirostris n. sp., Polyipnus bandeli n. sp., Lampanyctus ipunensis n. sp., Physiculus pichi n. sp., Coelorinchus fidelis n. sp., Coelorinchus rapelanus n. sp., Nezumia epuge n. sp., Paracarapus chilensis n. gen. et n. sp., Lepophidium chonorum n. sp., Lepophidium mapucheorum n. sp., Sirembola supersa n. sp., Spectrunculus sparsus n. sp., Pseudonus humilis n. sp., Capromimus undulatus n. sp., Agonopsis cume n. sp., Cottunculus primaevus n. sp., Kuhlia orientalis n. sp., Citharichthys parvisulcus n. sp., Citharichthys vergens n. sp., Achirus australis n. sp., Achirus chungkuz n. sp.
      PubDate: 2021-07-27
      DOI: 10.1186/s13358-021-00228-w
       
  • Preservation of nautilid soft parts inside and outside the conch
           interpreted as central nervous system, eyes, and renal concrements from
           the Lebanese Cenomanian

    • Free pre-print version: Loading...

      Abstract: Abstract Nautilid, coleoid and ammonite cephalopods preserving jaws and soft tissue remains are moderately common in the extremely fossiliferous Konservat-Lagerstätte of the Hadjoula, Haqel and Sahel Aalma region, Lebanon. We assume that hundreds of cephalopod fossils from this region with soft-tissues lie in collections worldwide. Here, we describe two specimens of Syrionautilus libanoticus (Cymatoceratidae, Nautilida, Cephalopoda) from the Cenomanian of Hadjoula. Both specimens preserve soft parts, but only one shows an imprint of the conch. The specimen without conch displays a lot of anatomical detail. We homologise the fossilised structures as remains of the digestive tract, the central nervous system, the eyes, and the mantle. Small phosphatic structures in the middle of the body chamber of the specimen with conch are tentatively interpreted as renal concrements (uroliths). The absence of any trace of arms and the hood of the specimen lacking its conch is tentatively interpreted as an indication that this is another leftover fall (pabulite), where a predator lost parts of its prey. Other interpretations such as incomplete scavenging are also conceivable.
      PubDate: 2021-07-23
      DOI: 10.1186/s13358-021-00229-9
       
  • First discovery of nautilids from the Albian–Cenomanian succession of
           the Koppeh Dagh Basin, NE Iran

    • Free pre-print version: Loading...

      Abstract: Abstract The Aitamir Formation, situated in the Koppeh Dagh Basin in the northeast of Iran, is known for its well-exposed Albian-to-Cenomanian succession. Although geologists previously documented a number of macro- and microfossils, no nautilids had been discovered until now to our knowledge. Here, we present lower Albian and middle Cenomanian nautilids from the Koppeh Dagh Basin for the first time. This discovery is also the first record of Cretaceous nautilids from Iran. We identified the specimens as Eutrephoceras clementianum (d’Orbigny 1840), E. sublaevigatum (d’Orbigny 1850), E. bouchardianum (d’Orbigny 1840) and Eutrephoceras sp. These specimens occur in horizons situated between several ammonite-bearing levels, which allowed us to more precisely constrain age estimates for the recovered nautilid specimens. E. clementianum could not be dated precisely but likely comes from between late Aptian ammonite index Hypacanthoplites uhligi and middle Albian Hoplites (Hoplites) baylei. E. sublaevigatum occurs just above the late Albian ammonites Mariella bergeri and Semenoviceras michalskii and below the Mantelliceras mantelli Zone. At the upper part of the section, E. bouchardianum and Eutrephoceras sp. were collected from lower Albian beds, which correspond to the Mantelliceras mantelli and Mantelliceras dixonii zones. These new findings contribute to our knowledge of the geographical distribution and stratigraphic range of Albian–Cenomanian nautilid species.
      PubDate: 2021-07-21
      DOI: 10.1186/s13358-021-00230-2
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 34.231.247.88
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-