Vertebrate Assemblages Research Articles

Le dauphin à dents de requin Squalodon (Cetacea: Odontoceti) du remarquable assemblage de vertébrés marins de Montagna della Majella (Formation de Bolognano, Italie centrale).

The extinct family Squalodontidae consists of heterodont, medium-sized odontocetes, featuring a long rostrum that houses large, procumbent incisors and heavily ornamented postcanine teeth carrying accessory denticles, hence their vernacular name, dolphins. These longirostrine toothed whales are often seen as bridging the anatomical gap between archaic Oligocene odontocetes and their late Miocene to Holocene relatives. Possibly among the major marine predators of their time, the shark-toothed dolphins are important components of several lower Miocene marine-mammal assemblages from the North Atlantic and Mediterranean/Paratethysian realms. In the present work, a partial skull of Squalodontidae is described from the strata of the Bolognano Formation cropping out in the northeastern sector of the Montagna della Majella massif (Abruzzo, central Italy), which has previously yielded a rich lower Miocene marine-vertebrate assemblage, including eleven taxa of elasmobranchs as well as subordinate teleosts and very fragmentary remains of marine reptiles and mammals. The specimen consists of the anterodorsal portion of a rostrum, preserving parts of both premaxillae and left maxilla, and the anteriormost seven upper left teeth. This partial skull is here identified as belonging to the genus Squalodon, whose presence in the Montagna della Majella vertebrate assemblage had already been tentatively proposed on the basis of two fragmentary teeth. The paleontological significance of this find is discussed in the broader framework of the Euromediterranean record of Squalodon.

Using vertebrate environmental DNA from seawater in biomonitoring of marine habitats.

Conservation and management of marine biodiversity depends on biomonitoring of marine habitats, but current approaches are resource‐intensive and require different approaches for different organisms. Environmental DNA (eDNA) extracted from water samples is an efficient and versatile approach to detecting aquatic animals. In the ocean, eDNA composition reflects local fauna at fine spatial scales, but little is known about the effectiveness of eDNA‐based monitoring of marine communities at larger scales. We investigated the potential of eDNA to characterize and distinguish marine communities at large spatial scales by comparing vertebrate species composition among marine habitats in Qatar, the Arabian Gulf (also known as the Persian Gulf), based on eDNA metabarcoding of seawater samples. We conducted species accumulation analyses to estimate how much of the vertebrate diversity we detected. We obtained eDNA sequences from a diverse assemblage of marine vertebrates, spanning 191 taxa in 73 families. These included rare and endangered species and covered 36% of the bony fish genera previously recorded in the Gulf. Sites of similar habitat type were also similar in eDNA composition. The species accumulation analyses showed that the number of sample replicates was insufficient for some sampling sites but suggested that a few hundred eDNA samples could potentially capture >90% of the marine vertebrate diversity in the study area. Our results confirm that seawater samples contain habitat‐characteristic molecular signatures and that eDNA monitoring can efficiently cover vertebrate diversity at scales relevant to national and regional conservation and management.

DIPLODON CF. COLHUAPIENSIS (BIVALVIA - HYRIIDAE) IN THE SANTA CRUZ FORMATION (EARLY-MIDDLE MIOCENE), AT THE RÍO SANTA CRUZ, PATAGONIA, ARGENTINA. STRATIGRAPHIC AND PALEOENVIRONMENTAL CONSIDERATIONS

The Santa Cruz Formation (Early–Middle Miocene) is one of the most widespread sedimentary units of the Argentine Patagonia. This unit contains an abundant and taxonomically diverse fossil vertebrate fauna, especially in mammals. Thus, the paleoecological and paleoenvironmental information derives mainly from the analysis of the vertebrate assemblages, as well as from the ichnological and paleobotanical evidence. The record of freshwater bivalves assigned to the species Diplodon cf. colhuapiensis Ihering, 1903 from the Santa Cruz Formation, collected in the locality of Barrancas Blancas (Estancia Santa Lucía), at Río Santa Cruz, allows us to infer the particular paleoenvironmental conditions setting during the deposition of the bearing levels. Considering this record, we propose that Diplodon, which was originally assigned to the “Sehuenense stage” (piso sehuenense of F. Ameghino), could have come from the Early–Middle Miocene of the Santa Cruz Formation. In this sense, the specimens referred to Diplodon cf. colhuapiensis suggest the existence of an established community of Hyriidae mollusks at the upper-middle levels of the Santa Cruz Formation. The presence of freshwater bivalves suggests that the depositional environment of this unit included the existence of water courses. The identification of the genus in the Santa Cruz Formation validates its presence in the Early Miocene and extends its southern distribution to the latitude of Río Santa Cruz (~ 50o S).

Spatial-seasonal variability of vertebrate assemblages in a Neotropical tidal flat: Recommendations for monitoring the potential impacts of port expansion

Our study aimed to understand the nekton biodiversity of a Neotropical tidal flat in southeastern Brazil (Araçá Bay) and to support its conservation, due to a potential port expansion, by determining: (1) the structure of the local assemblage of nekton (birds, fishes and turtles); (2) its spatial and seasonal variability; (3) potential processes explaining such variability; and (4) the impacts and monitoring measures related to port expansion. Araçá Bay has a high vertebrate richness (205 species, consisting of at least 126 fishes, 78 birds and one turtle species), two invasive fish species, 11 endangered species, a large abundance of target species in fisheries, and a high functional diversity in terms of life history and feeding habits. Mullets, mojarras, sardines and gobies dominate the fish assemblage, while the avifauna is mainly composed of herons and plovers. Green turtles (juveniles) were registered during high tides in all seasons. The low-tide bird and high-tide fish assemblages are spatially structured varying between the inner and the outer area of the flat. In tide pools, fish fauna varies according to bottom type. Juvenile fish predominate; fish assemblage varied according to recruitment and bird’s varied seasonally due to migration. The unique mosaic of habitats and the high productivity of the bay explain the high nekton diversity and make it a locally critical ecosystem for feeding, breeding, and growth. The port expansion would decrease the habitat diversity and productivity in the bay, negatively affecting nekton populations and their ecosystem services. We propose key aspects for nekton monitoring to mitigate port-related impacts.

A large sized megalosaurid (Theropoda, Tetanurae) from the late Jurassic of Uruguay and Tanzania

We report the first Jurassic remains that can confidently be referred to a megalosaurine theropod in Uruguay and Tanzania. This identification is sustained on a detailed morphological study. The large size of both teeth (>70 mm in lateral teeth) and denticles (<7 denticles per 5 mm), the clearly visible braided enamel texture, the centrally placed and apically restricted mesial carina in mesial teeth, and general shape of the teeth strongly resembles Torvosaurus. This is coherent with multivariate analyses of two datasets of large theropod teeth measurements, and also with the results of a phylogenetic analysis of theropod teeth. The presence of Torvosaurus in the Tacuarembó Formation of Uruguay further strengthens the Late Jurassic age proposed for the fossiliferous horizon. The Uruguayan megalosaurid would represent the apex predator in the vertebrate assemblage. The occurrence of megalosaurids in the Late Jurassic of Uruguay (the first unquestionable megalosaurid from South America) and Tanzania also greatly expands the geographical range of the family.

Bite marks and predation of fossil jawless fish during the rise of jawed vertebrates.

Although modern vertebrate diversity is dominated by jawed vertebrates, early vertebrate assemblages were predominantly composed of jawless fishes. Hypotheses for this faunal shift and the Devonian decline of jawless vertebrates include predation and competitive replacement. The nature and prevalence of ecological interactions between jawed and jawless vertebrates are highly relevant to both hypotheses, but direct evidence is limited. Here, we use the occurrence and distribution of bite mark type traces in fossil jawless armoured heterostracans to infer predation interactions. A total of 41 predated specimens are recorded; their prevalence increases through time, reaching a maximum towards the end of the Devonian. The bite mark type traces significantly co-occur with jawed vertebrates, and their distribution through time is correlated with jawed vertebrate diversity patterns, particularly placoderms and sarcopterygians. Environmental and ecological turnover in the Devonian, especially relating to the nekton revolution, have been inferred as causes of the faunal shift from jawless to jawed vertebrates. Here, we provide direct evidence of escalating predation from jawed vertebrates as a potential contributing factor to the demise and extinction of ostracoderms.

Marine Vertebrate Biodiversity and Distribution Within the Central California Current Using Environmental DNA (eDNA) Metabarcoding and Ecosystem Surveys

Environmental DNA (eDNA) metabarcoding is a new approach for assessing marine biodiversity that may overcome challenges of traditional monitoring and complement both existing surveys and biodiversity assessments. There are limited eDNA studies that evaluate vertebrate biodiversity in the marine environment or compare patterns of biodiversity with traditional methods. This study uses eDNA metabarcoding of the mitochondrial 12S rRNA genes present in seawater samples to characterize vertebrate biodiversity and distribution within National Marine Sanctuaries located in the California Current upwelling ecosystem. The epipelagic community in the study region has been monitored using traditional (mid-water trawl and marine mammal) survey methods since 1983. During 2016 and 2017, we concurrently sampled the epipelagic community using traditional survey methods and water for eDNA analysis to assess agreement among the methods. We collected replicate eDNA samples from 25 stations at depths of 10, 40, and 80 m, resulting in 131 small volume (1 L) environmental water samples to examine eDNA sequences. Across the eDNA and traditional survey methods, 80 taxa were identified. Taxa identified by eDNA partially overlapped with taxa through trawl and marine mammal surveys, but more taxa were identified by eDNA. Diversity and distribution patterns of marine vertebrates inferred from eDNA sequences reflected known spatial distribution patterns in species occurrence and community structure (e.g., cross-shelf and alongshore patterns). During both years we identified fishery taxa Sebastes (rockfish), Merluccius (hake), Citharichthys (sanddab), and Engraulis (anchovy) across the majority of the stations using eDNA metabarcoding. The marine vertebrate assemblage identified by eDNA in 2016 was statistically different from the 2017 assemblage and more marine mammals were identified in 2017 than in 2016. Differences in assemblages identified by eDNA were coincident with different oceanographic conditions (e.g., upwelling and stratification). In 2016 weak upwelling and warmer than average conditions were measured, and vertebrate assemblages were not different among ecological regions (Point Reyes, Pescadero, and Monterey Bay). While in 2017, average upwelling conditions returned, vertebrate assemblages differed at each region. This study illustrates that eDNA provides a new baseline for vertebrate assessments that can both augment traditional biomonitoring surveys and aid our understanding of changes in biodiversity.

New materials and an overview of Cretaceous vertebrates from the Chubut Group of the Golfo San Jorge Basin, central Patagonia, Argentina

In this paper, we present an updated revision of fossil vertebrates from the Chubut Group, Golfo San Jorge Basin, while also describing some new remains. Extensive exposures of both Lower and Upper Cretaceous sedimentary sequences are present in central Patagonia. These outcrops have, over the past several decades, yielded a varied vertebrate fauna, including fishes, turtles, crocodyliforms, pterosaurs, and dinosaurs, currently herein characterized and described. Although vertebrate diversity in the Chubut Group in central Patagonia is remarkable, the most abundant vertebrates recovered are dinosaurs. The Matasiete Formation (Hauterivian?–Albian) is markedly less prolific in terms of fossils discoveries than either the Bajo Barreal Formation (Cenomanian–early Turonian) or the recently recognized Lago Colhué Huapi Formation (Coniacian–Maastrichtian). The Bajo Barreal fauna is, at a high level, typical of coeval Gondwanan faunas. However, interestingly, several taxa occupy a basal position within their respective groups. The Lago Colhué Huapi Formation has produced a more derived vertebrate fauna, again similar to those from other Gondwanan regions. Finally, in a broad context, the new materials described augment our understanding of Cretaceous terrestrial vertebrate assemblage of central Patagonia and add to the generally meager record of vertebrate in the Cretaceous of the Southern Hemisphere.

New data for the late Upper Palaeolithic in the Cantabrian region: Arangas Cave (Cabrales, Asturias, Spain)

This paper presents new archaeological evidence recorded in the late Pleistocene levels from Arangas cave (Northern Spain). The main goal is to reconstruct the subsistence strategies of the hunter-gatherer groups that occupied the cave between 18,500 and 12,500 cal BP from the integral study of biotic and abiotic remains. Anthracological study reveals that during the Lower Magdalenian (Levels G and F) and Azilian (Level E) daily firewood was collected mainly from species such us as Scots pine nowadays disappeared around the catchment area of the cave or the common oak located in sheltered areas of the hillsides. Faunal remains indicate that the diet was based almost exclusively in the hunting of several ungulates species (red deer, Iberian ibex and chamois). Small vertebrate assemblage is only abundant during the Level G where an open humid and not very cold environment has been inferred.The abiotic evidence is characterized by a lithic assemblage made in local raw materials (above all quartzite). Whereas in the levels dated during the Lower Magdalenian the retouched implements are typologically unrepresentative, in the Azilian level they are more characteristic, above all with the classification of a “thumbnail” end scraper.

P.817 The effects of different length of displacement on the war-related stress induced health outcomes in internally displaced persons in Georgia

Fragments of turtle shell are known from several Upper Cretaceous formations in Mexico, including Corral de Enmedio and Packard Shale, Sonora; Aguja and Cerro del Pueblo, Coahuila; San Carlos, Chihuahua; El Gallo, Baja California; and Ocozocoautla, Chiapas. Turtles are important members of Upper Cretaceous vertebrate assemblages throughout North America and are considered a useful tool to define biogeographic patterns. The Upper Cretaceous sedimentary rocks exposed in the Aguja Formation record the final transgressive/regressive sequence of the Western Interior Cretaceous Seaway and the subsequent transition from a marine to terrestrial environment. The total area of outcrops is small compared to correlative exposures of these strata elsewhere in North America, in spite of this, numerous invertebrate and vertebrate fossils have been collected. The Aguja Formation in Texas preserves one of the southernmost well-studied Upper Cretaceous (Campanian) terrestrial vertebrate faunas in North America; contrary to what happens with the outcrops in northern Chihuahua, where the record of terrestrial vertebrates is scarce and especially those related to Testudines. Non-marine strata of the Aguja Formation do not appear to be present farther south in Mexico, and this is the reason why the Aguja fauna is relevant to documenting latitudinal variation in Campanian continental faunal associations. In this paper, the richness of Upper Cretaceous turtles collected from three localities within the Aguja Formation in Chihuahua is reviewed. Six taxa are recognized based on shell fragments with distinctive sculpture patterns: stem cryptodires, including cf. Baenidae, c.f. Denazinemys nodosa and cf. Compsemys victa, and crown group cryptodires including trionychians (trionchids and Basilemys sp.) and a kinosternoid (cf. Yelmochelys rosarioae). With the recognition of these taxa, new records are reported for the Aguja Formation (e.g. cf. Yelmochelys rosarioae) and Mexico (e.g. c.f. Denazinemys nodosa). The knowledge of Cretaceous turtle richness of the Aguja Formation and Mexico is increased and confirms the proposal of the variability richness along the North American localities. This latitudinal variability suggests that at any time turtles would have had a climatically controlled northern limit of distribution, and the richness of turtles would have decreased as this limit was reached.

Fish, amphibian and reptilian faunas from latest Oligocene to middle Miocene localities from Central Turkey

In this paper, we describe ectothermic vertebrate assemblages from the Kargi 1, Kargi 2, Kargi 3, Harami1, Harami 3, Hancili, Kesekoy, Candir and Bagici localities in Turkey. The ages of these localities range from the latest Oligocene to the middle Miocene. The preserved non-mammalian fauna of the studied localities includes fishes (Luciobarbus sp., Barbus sp., Luciobarbus vel Barbus sp., aff. Capoeta sp., Barbini indet., Leuciscus sp.), anurans (Bufonidae indet. (? Pseudepidalea sp.), Pelobatidae indet., Latonia sp., Palaeobatrachidae indet.), caudates (Salamandra sp.), lizards (Pseudopus sp., Lacertidae indet. 1, Lacertidae indet. 2, Lacertidae indet. 3, Lacertidae indet. 4, Blanidae indet. (?Blanus sp.)), snakes (Albaneryx sp., Erycinae indet.) and crocodiles (Crocodylia indet.). Here, we describe, for the first time, the fossil occurrences of the genera Salamandra, Albaneryx and Pseudopus from Anatolia, as well as the first fossil representative of the clade of the Western Asian lizards (Lacertidae indet. 3). Our study provides the earliest known fossil occurrences of the genera Luciobarbus, Barbus, Pseudopus and Albaneryx. Palaeobiogeographic relationships of each studied group are discussed and compared with the European and Asiatic records. A tentative palaeoenvironmental reconstruction is provided for each locality.

Anatomy, Relationships, and Paleobiology of Cambaytherium (Mammalia, Perissodactylamorpha, Anthracobunia) from the lower Eocene of western India

ABSTRACT The anatomy of Cambaytherium, a primitive, perissodactyl-like mammal from the lower Eocene Cambay Shale Formation of Gujarat, India, is described in detail on the basis of more than 350 specimens that represent almost the entire dentition and the skeleton. Cambaytherium combines plesiomorphic traits typical of archaic ungulates such as phenacodontids with derived traits characteristic of early perissodactyls. Cambaytherium was a subcursorial animal better adapted for running than phenacodontids but less specialized than early perissodactyls. The cheek teeth are bunodont with large upper molar conules, not lophodont as in early perissodactyls; like perissodactyls, however, the lower molars have twinned metaconids and m3 has an extended hypoconulid lobe. A steep wear gradient with heavy wear in the middle of the tooth row suggests an abrasive herbivorous diet. Three species of Cambaytherium are recognized: C. thewissi (∼23 kg), C. gracilis (∼10 kg), and C. marinus (∼99 kg). Body masses were estimated from tooth size and long bone dimensions. Biostratigraphic and isotopic evidence indicates an age of ca. 54.5 Ma for the Cambay Shale vertebrate fauna, the oldest Cenozoic continental vertebrate assemblage from India, near or prior to the initial collision with Asia. Cambaytheriidae (also including Nakusia and Perissobune) and Anthracobunidae are sister taxa, constituting the clade Anthracobunia, which is sister to Perissodactyla. We unite them in a new higher taxon, Perissodactylamorpha. The antiquity and occurrence of Cambaytherium—the most primitive known perissodactylamorph—in India near or before its collision with Asia suggest that Perissodactyla evolved during the Paleocene on the Indian Plate or in peripheral areas of southern or southwestern Asia.

TESTING THE DAPTOCEPHALUS AND LYSTROSAURUS ASSEMBLAGE ZONES IN A LITHOSTRATOGRAPHIC, MAGNETOSTRATIGRAPHIC, AND PALYNOLOGICAL FRAMEWORK IN THE FREE STATE, SOUTH AFRICA

ABSTRACT The vertebrate-fossil record in the Karoo Basin has served as the accepted model for how terrestrial ecosystems responded to the end-Permian extinction event. A database of several hundred specimens, placed into generalized stratigraphies, has formed the basis of a step-wise extinction scenario interpreted by other workers as spanning the upper Daptocephalus (=Dicynodon) to Lystrosaurus Assemblage Zones (AZ). Seventy-three percent of specimens used to construct the published model originate from three farms in the Free State: Bethel, Heldenmoed, and Donald 207 (Fairydale). The current contribution empirically tests: (1) the stratigraphic resolution of the vertebrate record on these farms; (2) whether a sharp boundary exists that delimits the vertebrate assemblage zones in these classic localities; and (3) if the Lystrosaurus AZ is of early Triassic age. We have used a multi-disciplinary approach, combining lithostratigraphy, magnetostratigraphy, vertebrate biostratigraphy, and palynology, to test these long-held assumptions. Previously reported vertebrate-collection sites have been physically placed into a litho- and magnetostratigraphic framework on the Bethel and Heldenmoed farms. The reported assemblage-zone boundary is used as the datum against which the stratigraphic position of vertebrates is compared and a preliminary magnetostratigraphy constructed. We find specimens of the Daptocephalus AZ originate in the Lystrosaurus AZ (as currently defined) and vice versa, and discrepancies between reported and field-checked stratigraphic positions below or above the assemblage-zone boundary often exceed 30 m. Hence, the utility of the data set in defining a sharp or abrupt biozone boundary is questionable. We further demonstrate the presence of a stratigraphically thick reverse polarity magnetozone that encompasses the reported assemblage-zone boundary, implying that these rocks are not correlative with the end-Permian event, which is reported to lie in a normal polarity chron. A latest Permian age is supported by palynological data from the Lystrosaurus AZ on the Donald 207 (Fairydale) farm, with equivalence to Australian (APP602) and Eastern Cape Province assemblages. We conclude that the turnover from the Daptocephalus to Lystrosaurus Assemblage Zones is more protracted than envisioned, it is not coincident with the end-Permian event as recognized in the marine realm, and little evidence exists in support of a three-phased extinction model based on vertebrate assemblages in the Karoo Basin.

Implications of modern Barn owls pellets analysis for archaeological studies in the Middle East

Situated at the crossroad between Africa, Asia and Europe, the Middle East is an important region for the knowledge of human and mammal migrations. Among mammals, fossil small mammals are good proxies for palaeoenvironmental reconstructions, and can also play the role of markers of prehistoric movements. In the aim to better characterize the origins and the palaeoecological signal delivered by the small vertebrate assemblages in Middle East archaeological sites, we performed a taxonomic and taphonomic study of the small mammal remains found in pellets from Barn owl (Tyto alba) from a poorly known region of South of Turkey at the Syrian border, east of Euphrates River. This will constitute the first available taphonomic referential for this region.The studied sample constituted by more than 40 disintegrated pellets provided 2503 rodent skeletal elements. The most common preys are Meriones tristami, followed by Mus musculus. The taphonomic study showed that our assemblage fits well with a predator category of light modification. Regarding the preservation, our mean bone relative abundance reached 82% and the bone fragmentation showed that more than 77% of our sample is intact. The digested elements represented 22% and the low to moderate grades were dominant (83.5%). Implications for environmental and climatic reconstructions based on small mammal communities were also explored using BioclimaticModel and Habitat Weighting methods.

New marine reptile fossils from the Late Jurassic of Poland with implications for vertebrate faunas palaeobiogeography

A new marine vertebrate assemblage from the Late Jurassic (late Kimmeridgian) at Krzyżanowice near Iłża in the NE margin of the Holy Cross Mountains in Poland is described. This new locality is rich in fossils of coastal and pelagic reptiles. The most frequent fossils are plesiochelyid turtle shell fragments and pliosaurid skull bones and teeth. The Krzyżanowice vertebrate assemblage is similar to the Late Jurassic Boreal/Sub-Boreal localities of the Kimmeridge Clay in Great Britain and Svalbard Archipelago in the Arctic, in the presence of pliosaurids and long-necked plesiosaurids. However, plesiochelyid turtles and crocodylomorphs are similar to those from the Mediterranean/Sub-Mediterranean sites of the northern border of the Tethys Ocean, as, for example, in the Swiss Jura Mountains and Southern Germany. This unique composition of the Krzyżanowice vertebrate fauna demonstrates that, during the Late Jurassic this new locality was located in the transitional palaeobiogeographic line referred to in this paper as the “Matyja-Wierzbowski Line”. The new palaeobiogeographical reconstructions of Late Jurassic of Europe are based on the composition of the Krzyżanowice locality and other sites with similar turtle-pliosaurid faunas which formed a long-term, stable ecological sympatry in marine ecosystems of the European Archipelago.

Presence of the Jehol Biota turtle &amp;lt;i&amp;gt;Ordosemys liaoxiensis&amp;lt;/i&amp;gt; in the Early Cretaceous Hengtongshan Formation of southern Jilin Province, China

Abstract. Recently, a vertebrate assemblage of the Jehol Biota has been reported from the Early Cretaceous Hengtongshan Formation of Xingling Town, Meihekou City, Jilin Province, China. It is dominated by the fishes Lycoptera and Sinamia and the sinemydid turtle Ordosemys. Here, we describe the turtle specimens and referral to Ordosemys liaoxiensis, otherwise known from the older Yixian Formation of the Jehol Biota. It is characterized by a subcircular shell, wide vertebral scales, well-developed plastral fenestrae, and a major contribution from the xiphiplastra to enclose the hypo-xiphiplastral fenestra. As the first Mesozoic turtle of Jilin Province, this record represents the first tetrapod to indicate the presence of the Jehol Biota in the region. Given the geographic and temporal distance from the Yixian Formation, future collections from the Hengtongshan Formation have good potential for evaluating spatiotemporal patterns of the Jehol Biota.

Silurian vertebrate remains from the Oslo Region, Norway, and their implications for regional biostratigraphy

Several vertebrate assemblages are described from the Silurian of the Oslo Region, Norway, based on the review and revision of previous reports of microremains, as well as unpublished material from ...

A Middle Miocene (~14 Ma) vertebrate assemblage from Palasava, Rapar Taluka, Kutch (Kachchh) District, Gujarat State, western India

ABSTRACT The present article aims to record a recently discovered middle Miocene vertebrate assemblage (including marine and terrestrial mammals) from Palasava, Kutch (Kachchh) District, Gujarat State, western India. The faunal assemblage comprising fishes, chelonians, crocodiles, snakes, birds and mammals is significant in terms of palaeoecology, palaeoenvironment and biostratigraphy of the region and yields evidence concerning its biogeographic affinities linked to Neogene Eustatic history. Palasava fauna together with previously known Neogene (particularly Miocene) vertebrate assemblages from the Kutch region indicates the presence of a riverine-estuarine system(s) linked to the sea, i.e. the depositional centres were quite close to the sea. Furthermore, the Palasava vertebrate assemblage (recorded herein) points towards a prevalence of warm, humid/wet, tropical to sub-tropical environmental conditions. The terrestrial mammalian assemblage from Palasava represents at least seven families with six of the terrestrial mammalian taxa identified herein to the genus level, namely: Sanitherium, Sivameryx, Brachypotherium, Zygolophodon, Gomphotherium, and Deinotherium. The overall assemblage (including Zygolophodon and Deinotherium) is indicative of a Middle Miocene, 14 ± 2 Ma (Langhian to Serravallian) age for the sedimentary succession at Palasava. Furthermore, a ~ 14 Ma age for the Palasava fauna indicates a correlation to regression cycle R5 in the Tagus Valley succession of Portugal.

The Formation of a Marine Bonebed at the Upper Cretaceous Dinosaur Park - Bearpaw Transition of West - Central Saskatchewan, Canada

A marine bonebed from the Campanian (Upper Cretaceous) Bearpaw – Dinosaur Park Formation transition, containing both micro- and macrovertebrate fossils and trace fossils, was discovered in west-central Saskatchewan, Canada. The bonebed formed during transgression of the Western Interior Seaway, with the stratigraphy of the area displaying extensive interfingering of these terrestrial and marine facies. The macrovertebrate fossils occur in a layer of fine-grained, unconsolidated sand. Directly overlying this stratum is a layer of sulfur-rich, medium-grained sandstone, containing the microvertebrate fossils. Most of the material in both layers is highly encrusted in gypsum. The bonebed formed in a barrier island system over three stages: original deposition of marine reptile bones in a silled basin over a period of sediment starvation, redeposition and burial of the bone material due to higher energy flow through the basin, and deposition of bony and cartilaginous fish material during a period of water stratification and subsequent euxinic conditions. Because sediment deposition rates were low when the marine reptile bones accumulated, these elements spent extended periods at the sediment-water interface, allowing them to become bioeroded. The bioerosion at this site takes two main forms: parallel-sided boreholes about one cm wide, and extensive hollowing out of the cancellous bone. Although the invertebrate tracemakers were not preserved the boreholes resemble clavate borings made by bivalves, and the hollowing could have been caused by polychaete worms or grazing gastropods. The presence of sulfur-rich deposits and chemosymbiotic Chondrites isp. traces in the layer above the bonebed suggest the development of a stratified water column in the basin, with euxinic (anoxic and sulfuric) conditions near the seafloor. Disruption of the water column culminated in a mass die-off of non-air breathing vertebrates in the surface waters and constitutes the microvertebrate layer of the bonebed. Marine reptile bonebeds are rare in the fossil record, and this site represents the first time a vertebrate assemblage has been described from a barrier island system in Saskatchewan. This study will help further our understanding of the transition between the Dinosaur Park and Bearpaw formations, two of the best-known Campanian fossil-bearing deposits in Canada.

The Evolution of Color Pattern in Butterflyfishes (Chaetodontidae).

Coral reef fishes constitute one of the most diverse assemblages of vertebrates on the planet. Color patterns are known to serve a number of functions including intra- and inter-specific signaling, camouflage, mimicry, and defense. However, the relative importance of these and other factors in shaping color pattern evolution is poorly understood. Here we conduct a comparative phylogenetic analysis of color pattern evolution in the butterflyfishes (Chaetodontidae). Using recently developed tools for quantifying color pattern geometry as well as machine learning approaches, we investigate the tempo of evolution of color pattern elements and test whether ecological variables relating to defense, depth, and social behavior predict color pattern evolution. Butterflyfishes exhibit high diversity in measures of chromatic conspicuousness and the degrees of fine versus gross scale color patterning. Surprisingly, most diversity in color pattern was not predicted by any of the measures of ecology in our study, although we did find a significant but weak relationship between the level of fine scale patterning and some aspects of defensive morphology. We find that the tempo of color pattern diversification in butterflyfishes has increased toward the present and suggest that rapid evolution, presumably in response to evolutionary pressures surrounding speciation and lineage divergence, has effectively decoupled color pattern geometry from some aspects of ecology. Machine learning classification of color pattern appears to rely on a set of features that are weakly correlated with current color pattern geometry descriptors, but that may be better suited for the detection of discrete components of color pattern. A key challenge for future studies lies in determining whether rapid evolution has generally decoupled color patterns from ecology, or whether convergence in function produces convergence in color pattern at phylogenetic scales.