Geobios最新文献

Palaeogiraffa is a poorly understood giraffid genus from the Vallesian of Axios Valley (Northern Greece), Turkish Thrace and Central Turkey. The Axios Valley remains come from three non-contemporaneous Vallesian faunas from the localities: Pentalophos, Ravin de la Pluie, and Xirochori, whereas the Turkish remains come from the Vallesian faunas of Middle Sinap, Yulafli, and Küçükçekmece. Remains from Pentalophos and Ravin de la Pluie were described as congeneric with the Iberian Deccenatherium, although they were later attributed to a new, distinct genus known by three different species: Palaeogiraffa macedoniae, Palaeogiraffa pamiri, and Palaeogiraffa major. The type species of the genus, Pg. macedoniae, was based on the most abundant Pentalophos material, while the rest of the species was established mainly on size difference criteria. Here we provide a review of the Palaeogiraffa material in order to (i) test its validity, (ii) re-discuss hypotheses about the genus phylogenetic relationships with other Late Miocene giraffids, and (iii) re-explore intrageneric diversity and number of recognized species based on the available Eastern Mediterranean samples. We confirm Palaeogiraffa as a distinct genus from other Late Miocene giraffids based on its unique proportions, as well as its dental and postcranial morphology. Furthermore, we endorse the likelihood of Palaeogiraffa being phylogenetically linked to the sivatherine lineage, based mainly on its dental and metatarsal morphological features. The generic attribution of specimens from Xirochori, Ravin de la Pluie, Middle Sinap, Yulafli and Küçükçekmece to Palaeogiraffa is adequately supported by the present data. Nevertheless, the recognition of three species is more open to discussion, though they should be retained until more material is available.

In this paper, we provide the first data on large (cm-sized) coprolites (represented by three morphotypes) comprising a rare occurrence of eight specimens from a total of three vertebrate-bearing horizons identified within the Early Miocene (Aquitanian) Khari Nadi Formation and Middle Miocene (Burdigalian-Langhian) Chassra Formation, Kutch Basin, western India. The geochemical data confirm the phosphatic character of the investigated ichnofossils. The dominance of partly digested bone matter and presence of plant remains in all the three coprolite morphotypes reflects the omnivorous diet of the producers, which were most likely chelonians. The occurrence of an inclusion (in a coprolite specimen recorded in this study) showcasing an ultrastructure similar to mammalian dental enamel is a rarity in Neogene coprolite records. Additional biotic inclusions observed in the investigated coprolites include ostracods (assigned to genera Paractinocythereis, Hermanites, and Propontocypris); large planispiral benthic foraminifera including the genus Quinqueloculina; uniserial and biserial benthic foraminifera belonging to genus Textularia; marine calcareous algae genus Actinoporella; chrysophytes (resting spores or cysts of planktonic algae); sponge spicules (represented by the morphotypes Acanthoxea and Strongyle); freshwater diatom genus Aulacoseira; unidentified fungal remains; and phytoliths. Taken together, the biotic and abiotic (e.g., pyrite) inclusions, geochemical data and associated microbiota suggest that these ichnofossils were deposited in a dominantly coastal marine (intertidal) setting linked to a lacustrine/palustrine environment.

The new Prat de Cest locality (Narbonne-Sigean Basin, Aude, France) provides a rodent fauna composed of Pseudocricetodon thaleri, Simplomys aff. aljaphi, Vasseuromys cf. bergasensis, Plesiosminthus myarion and Rhodanomys occitanensis nov. sp. Eomyidae account for more than 78% of the material collected and reflect a humid and forested environment. The presence of Plesiosminthus myarion and Simplomys aff. aljaphi, the evolutionary stage of Pseudocricetodon thaleri, close to the population of Coderet (MP30) but displaying some derived characters shared by Early Miocene populations, and the intermediate morphology and size of R. occitanensis nov. sp. between Rhodanomys transiens and Rhodanomys schlosseri support a basal MN1 age for Prat de Cest. The glirid Vasseuromys cf. bergasensis is the first occurrence of this genus outside Spain and could also be the first occurrence of Vasseuromys bergasensis in the Early Miocene. The unique faunal association found in Prat de Cest paves the way for a possible subdivision of the MN1 biozone.

This contribution studies some paleobiological aspects of Opisthodactylus kirchneri, a fossil rheid from the Late Miocene of northwestern Argentina. We estimate the body mass of this species using an allometric equation based on long-legged birds. Besides, we estimate the maximum running speed by applying a previously published biomechanical model to study other living and fossil running birds. We perform multivariate analyses with hindlimb measurements used as biomechanical model inputs to compare the fossil rheid with other living ratite species. We found that O. kirchneri would not have been a swift runner as living rheids of South America. We identify the presence of a long distal hindlimb segment correlated with a novel adaptation to paleoenvironmental conditions in southern South America during the Late Miocene. We propose alternative interpretations based on these results and the hindlimb bone proportions.

The giant flightless bird Gastornis laurenti Mourer-Chauviré and Bourdon, 2020, has been described from a mandible, maxilla and quadrate discovered in the early Eocene locality of La Borie (middle Ypresian, reference level MP 8–9). This locality has yielded abundant fossil vertebrates. We describe here new postcranial remains of G. laurenti, a coracoideum assigned to Tegulavis corbalani nov. gen., nov. sp. (cf. Galliformes), a tarsometatarsus attributed to Papulavis annae nov. gen., nov. sp. (cf. Aramidae), and the tibiotarsus of a small gruiform related to either Walbeckornis or Messelornithidae. The study of the postcranial material confirms that the species G. laurenti differs from other species of Gastornis in many features. The avifauna from La Borie is not very diversified but matches well with the paleoenvironment, which consists of an alluvial flood plain with sparse vegetation, in a tropical climate.

LSID of publication: urn: lsid: zoobank.org: pub: 5BA44166-BBEZ-41E7-BG8C-8A1DBCBA14AB.

Vegavis iaai is without any doubt the most complete and well-known Mesozoic bird from Antarctica. In spite of being known by several specimens, its highly specialized postcranial anatomy has obscured the recognition of its phylogenetic affinities. Skull material from Vegavis is scarce, and the lower jaw is known by a relatively well-preserved articular region of a partially articulated specimen (MACN-PV 19.748). The aim of the present contribution is to describe this articular region and to analyze its potential phylogenetic information. The articular region of Vegavis shows a unique combination of characters that separates it from most Mesozoic lineages. On the contrary, its anatomy is congruent with that of neornithine birds, and particularly from the neoavian clade Aequorlitornithes. Detailed comparisons led to the recognition of several shared features, including a well-developed transverse crest posterior to the articular cotyles, that bears a well-developed lateral tubercle; a short and ventrally deflected retroarticular process; a dorsally exposed posterior fossa; tree cotyles for jaw articulation, with a well-developed caudal cotyle fused to the medial cotyle; and lateral crest anteriorly projected with respect to the lateral cotyle. The three-cotyle articulation of the jaw of Vegavis invited us to review skull anatomy of its close kin Polarornis. A review of the bones of Polarornis indicates that the element previously identified as a quadrate is an uncertain bone, and thus, skull-jaw articulation of this taxon remains unknown. In contrast with previous contributions, we were not able to find diagnostic features of the Galloanserae clade on Vegavis jaw. The neoavian-like jaw of Vegavis contrasts with the anseriform signature of its postcranium, suggesting that this bird held some kind of morphological mosaicism on its skeleton.

We report fossils of the Halcyornithidae from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The material includes remains of nine individuals of these small zygodactyl birds, which belong to at least seven different species, two of which are newly described. This documents a high species richness of halcyornithids in the London Clay, and these birds apparently underwent a significant radiation in the early Paleogene. One of the specimens includes a skull with a proportionally much smaller neurocranium than in Pseudasturides macrocephalus from Messel, suggesting an increased encephalization of halcyornithids towards the middle Eocene. A previously undescribed variation in sternum morphology of halcyornithids distinguishes the fossils we assign to the taxa Pulchrapollia and Cyrilavis and indicates that halcyornithids occupied disparate ecological niches. Furthermore, sternum morphology supports a sister group relationship between the halcyornithid taxa Pulchrapollia and Pseudasturides. The closest extant relatives of the Halcyornithidae remain elusive, but our new osteological data substantiate the hypothesis of a sister group relationship to the Messelasturidae, another group of Eocene birds with zygodactyl feet.

[http://zoobank.org/urn:lsid:zoobank.org:pub:DDC1768F-1389-4F36-92F6-46DA318A0C19].

We describe the vertebrate remains found in a Holocene deposit inside the Taiti Cave, Socotra Island (Yemen). The fossils were found in a sand dune occupying almost entirely the main cavity of the Cave, with some bones collected on the surface and the majority of them found under its surface, in particular below a tiny level of hardened sand, the latter probably related to a guano deposit. They were mostly isolated bones, but under the guano layer, some of them were aggregated and recognizable as belonging to owl pellets. The analysis of the vertebrate remains reveals a great prey diversity and, together with the location of the pellet accumulation and the almost perfect preservation of the remains, indicates that the deposit derived from a pellet accumulation made by Tyto alba. This hypothesis is corroborated by a Tyto alba beak fragment found in the Hoq cave, in a deposit of uncertain stratigraphic context. The data presented herein represent the first documented evidence of the presence of Tyto alba on Socotra Island and indicate the probable existence of a now extinct population of Tyto alba on the island during the Holocene, already extinct at the time of the first ornithological surveys during the XIX Century.

Night herons of the genus Nycticorax and Nyctanassa are adept island colonisers, occurring on a number of oceanic islands and island archipelagos. Continental species and those inhabiting large islands are generally not considered threatened, whereas night herons restricted to small, oceanic islands are particularly vulnerable to human interference. As a result, six out of nine described species and one subspecies, all derived from Nycticorax nycticorax, Nycticorax caledonicus or Nyctanassa violacea, are now extinct whereas a further three extinct species await description. The extinct island endemics generally exhibit morphological adaptations to an insular environment and diet, such as an increase or decrease in size, robust jaws and legs, and smaller wings with associated reduced flying ability than founding stock. Here I present an osteological comparison along with historical descriptions of the extinct, oceanic island night herons, with special reference to the Mascarene and Ascension fossil species, and Bonin Island subspecies, and show the degree of morphological changes between the founding and island taxa. I further discuss the reasons why they became extinct.