Guillaume Guinot, Sylvain Adnet, Gilles Cuny
et al.
Summary Estimating deep-time diversification patterns and the establishment of extant biodiversity represent major challenges in macroevolution. Fossil record data provide essential information to address these topics, but their heterogeneous temporal and geographical distributions require using analytical approaches to process these data. Gardiner et al. 1 (hereafter GEA) used a deep-learning model 2 and a fossil-occurrences dataset 3 to estimate neoselachian richness over the last 145 myr. Results and Discussion GEA 1 found that neoselachian diversity increased throughout the Cretaceous, was little impacted by the Cretaceous-Paleogene (K/Pg) mass extinction (~10% species loss), and peaked in the mid-Eocene but declined until the Present. While the Cretaceous increase in neoselachian richness is well known 4 , the other findings of GEA 1 are at odds with current knowledge. With the exception of lamniform sharks, the perceived decrease in species richness in the recent past is most likely due to a drop in available fossil record data combined with difficulties in identifying extant species in the fossil record 5 . Similarly, all previous analyses of the impact of the K/Pg mass extinction on elasmobranch diversification have reported high extinction rates, a marked diversity drop, and delayed recovery 6–7 , despite heterogeneity across clades, ecology, and geographical distribution 7 . Taking the K/Pg as an example, we demonstrate that the discrepancies between GEA 1 ’s results and current consensus is most likely due to a combination of incomplete, unverified, and incorrect fossil-occurrence data with inappropriate methodology.
Daniel T. Ksepka, Gerald Mayr, Alexander D. Clark
et al.
Abstract We report a new species of stem ibis (Threskiornithidae) from the early Eocene Fossil Butte Member of the Green River Formation. Rhynchaeites mcfaddeni n. sp. is represented by an articulated partial skeleton and was a diminutive species, with an estimated body mass of under 300 g. The holotype specimen is preserved in an unusual manner, leaving the skull, presacral vertebral column, wings, and feet in approximate life position despite the loss of the trunk, pelvis, tail, and upper legs. This peculiar mode of preservation may represent a case of the “stick ‘n’ peel” model of preservation, by which a portion of a carcass becomes firmly adhered to the sediment by substances released during decay. Like other members of the stem ibis genus Rhynchaeites , Rhynchaeites mcfaddeni n. sp. lacks the dense pitting of the bill tip associated with abundant Herbst corpuscles, which is developed in extant ibises. However, the new species differs from all stem and crown ibises in possessing a sharply tapering beak tip, which suggests a unique mode of foraging, possibly including prying mollusks from their shells. Given that Rhynchaeites messelensis Wittich, 1898 is one of the most common birds in the prolific Messel deposits but Rhynchaeites mcfaddeni n. sp. is represented by a single specimen after more than 50 years of intense collecting in the Green River Formation, it is likely the two species had divergent foraging strategies, with the former perhaps feeding closer to the lake margin and the latter in streams. UUID: http://zoobank.org/60d25b3b-9c76-4553-99c4-a390d3a5548d
Rana Mehroz FAZAL, HE Zhan-Wu, DU Bao-Pu, CHANG Mei-Jing, SHI Jing-Song, NI Xi-Jun, LI Qiang, ZHAO Ling-Xia
In 2015, the discovery of mammalian fossils, paleolithic artifacts, and burned bones in the Maoershan Cave of the Guilin Basin, northeastern Guangxi, indicated that it is a late Middle Pleistocene Paleolithic site. In 2021, stratigraphic sectioning and the systematic screening of small mammal sand samples were conducted. This paper presents a comprehensive account of the new material of the fruit bat Rousettus leschenaultii, accompanied by a concise overview of the non-volant micromammals that coexisted with it in the Quaternary sediments of the Maoershan Cave. This finding marks the second occurrence of fruit bat fossils in China, contributing to our understanding of the dental morphology and past geographical distribution of Rousettus. The micromammalian assemblage of the Maoershan Cave is composed of 3 orders, 9 families, 26 genera, and 30 species, and exhibits notable similarities with those of the late Middle Pleistocene Yumi Cave, Xinglong Cave, Yanhui Cave, Mawokou Cave, Zhongliangshan, and Chuan Cave faunas. The biochronology of the micromammalian assemblage from the Maoershan Cave has been determined to be consistent with the late Middle Pleistocene, providing a new assemblage in the Pleistocene mammalian faunal sequence in southern China. The presence of abundant oriental forested elements indicates that the Guilin Basin used to be a humid and warm subtropical forest paleoenvironment similar to the contemporary environment during the late Middle Pleistocene.
ALEXANDRE R.D. GUILLAUME, EDUARDO PUÉRTOLAS-PASCUAL, MIGUEL MORENO-AZANZA
The Guimarota beds (Kimmeridgian, Portugal) constitute one of the richest microvertebrate assemblages for the Upper
Jurassic, which include a diverse fauna of small reptiles. Among others, was described a new species of a small cho
ristodere, “Cteniogenys reedi”. The genus, also known from the Morrison Formation (Upper Jurassic, USA) and the
Kirtlington Mammal Bed (Middle Jurassic, UK), constitutes one of the oldest and most basal forms of this aquatic
reptile lineage considered to be ecologically similar to crocodylomorphs. However, later works considered this spe
cies to be a junior synonym, and challenged the assignment of some of this material, ascribing them to the aquatic
stem-lepidosaur Marmoretta. Here, we provided a revision of the published material from the Guimarota beds assigned
to Cteniogenys, together with unreported and mislabelled specimens. We confirmed that the Portuguese specimens are
probably non-conspecific with the taxa described in the Upper Jurassic of North America and in the Middle Jurassic of
England. Unfortunately, the lack of diagnostic features from the only valid species prevented to confirm the original
description as a distinct new species. Therefore, we only referred it to Cteniogenys aff. C. antiquus. We further supported
the presence of Marmoretta in the Upper Jurassic of Portugal, and erected a new species, Marmoretta drescherae. Those
occurrences support original palaeoenvironmental interpretations of the Guimarota beds as a wetland, probably close
to mangrove-like, with important freshwater inputs. The presence of Cteniogenys in Portugal further supports faunal
interchanges between North America, Europe, and potentially Northwestern Africa during the Jurassic/Cretaceous tran
sition, if later occurrences are to be confirmed. The presence of Marmoretta also extend the temporal range of this relict
reptile lineage at a time where squamates were radiating. However, its absence in other contemporary Jurassic localities,
notably in the Lourinhã and Morrison formations, could hint towards ecological differences between those assemblages.
The naturalist Carlos Rusconi firstly became in contact with important paleontologists such as Carlos Ameghino and Lucas Kraglievich in the Museum of Buenos Aires. Together with Lorenzo Parodi and Alfredo Castellanos, he formed an incipient group of vertebrate paleontologists. After the dispersion of this group at the end of 1930, Rusconi began to work at the Jardín Zoológico of Buenos Aires. Few years later, he was the Director of the provincial museum of Mendoza city, where he worked for 30 years. During this period, the Museo de Historia Natural of Mendoza experienced a great development, not only as an educational but also as a research institution. Rusconi recovered a significant paleontological collection mainly from Mendoza and close areas in the Cuyo Region. He reorganized the museum in different departments and started new inventory books. He published numerous articles on paleontology, among which those on Paleozoic trilobites and graptolites, Jurassic marine reptiles, and Triassic amphibians and fishes are greatly relevant. He defined a large number of new taxa, which are reflected in the numerous type materials stored at the museum. Rusconi worried about the paleontological heritage and even published a draft bill promoting a law to protect paleontological and archeological sites in Mendoza Province. The lack of provincial support to adequately maintain the museum and its collections led Rusconi to resign as Director in 1967. Despite his controversial personality and scientific isolation, Rusconi’s legacy in paleontology cannot be denied or ignored, especially when dealing with the paleontological record of Mendoza.
The Neogene interval witnessed three major waves of intercontinental dispersals by carnivoran mammals, mainly migrating from Eurasia to North America but with rare occurrences going in the opposite direction (e.g., Sthenictis, Leptarctus). The timing and composition of dispersers are thought to be controlled by filter-bridge mechanisms, but it is unclear what types of regional conditions promoted occasional dispersals outside of the three major waves. We study and report on new occurrences of small-bodied carnivorans from late Clarendonian-aged Black Hawk Ranch and Cuyama Valley fossil mammal assemblages in California. The relatively late occurrences of the mustelids Sthenictis and Hoplictis and the ailurid Alopecocyon in coastal regions of western North America suggest that nearshore dispersal corridors both facilitate and preserve faunal elements later than they might otherwise occur further inland. The availability of both marine- and terrestrially-derived food resources may be an important factor in allowing coastally dispersing taxa to be accommodated in those ecological communities compared to less heterogenous environments further inland.
Andre Nel, Valerie Ngo Muller, Romain Garrouste
et al.
Gallosynthemis bechlyi gen. et sp. nov., described from the Paleocene maar of Menat (Puy-de-Dôme, France) is the firstever fossil record of the dragonfly family Synthemistidae. It shows the main synapomorphies of the family, viz. hind wing with 3–5 costal braces (complete antenodal crossveins) alternating with non-aligned antenodals; presence of crossveins in median area and between CuP and PsA; absence of postsubnodal crossveins below first postnodal crossveins; in hind wing, a very large and elongate anal loop without a well-defined mid-rib; and CuAa without posterior branches. It belongs to the stem group of this family and is attributed to its own subfamily Gallosynthemistinae subfam. nov., characterized by a very long stem of hind wing cubitus anterior vein (autapomorphy), plus some symplesiomorphies such as sectors of arculus separated at their bases. While extant Synthemistidae sensu Bechly (2016) are Australasian, the present new taxon demonstrates that the family may have been much more widespread during the Paleocene. These dragonflies probably became extinct in the Northern Hemisphere in relation with the Cenozoic dramatic episodes of cooling.
AbstractAgalope oshikirii n. sp. (Zygaenidae, Chalcosiinae) is described from the uppermost Miocene–Pliocene Sanzugawa Formation in Akita Prefecture, northern Japan. Because we found a single fossil forewing in this study, we give a table of the forewing characters of various groups of the genus Agalope and related genera and compared them with this new species, confirming that it does not match any of the species. This is the first discovery of chalcosiine fossils in Japan and provides evidence of a historically broader distribution of the genus.http://zoobank.org/999828b5-4f91-470f-bc15-6b6fe7a8ec61
Leonardo Sebastián Filippi, Elena Previtera, Alberto Carlos Garrido
Kaijutitan maui is a basal titanosaur from the Sierra Barrosa Formation (Coniacian, Upper Cretaceous), Neuquén Basin, Patagonia Argentina. The Neuquén Basin in northwestern Patagonia, Argentina, holds the most important record of Cretaceous dinosaurs from South America. This work constitutes the first case of taphonomic and histological study of a dinosaur from the Rincón de los Sauces area. Kaijutitan is represented by cranial and postcranial materials of an adult individual of huge body size, preserved in clay sediments related to a floodplain environment. Bones were found disarticulated but associated, largely respecting their relative anatomical position. histological and diagenetic features of bones were analyzed in order to interpret the alteration degree of bone microstructure. Biostratinomic processes inferred are subaerial biodegradation, disarticulation, preburial weathering (cracking and flacking), and abrasion. Fossil-diagenetic processes comprise compaction, deformation, permineralization, and fracturing. Permineralization stages included infilling of bone cavities and fractures with sediments, iron oxides, calcite, or an iron oxide-calcite association during the burial history. Some characteristics suggest that the Kaijutitan specimen suffered weathering for a certain period of time before final burial and that biological activity in the carcass acted as a dispersal agent for the bones within the paleontological site.
Werner W. Schwarzhans, Orangel A. Aguilera, Torsten M. Scheyer
et al.
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. ZooBank LSID: urn:lsid:zoobank.org:pub:D05A3AA4-8F8E-4510-A07E-816C75790163. https://zoobank.org/4FE4BC4E-0EFC-4A32-A40F-CF561B98375F .
Juan M. Robledo, Silvina A. Contreras, Johanna S. Baez
et al.
The first pre-Quaternary representative of Alismataceae from South America is reported based on achenes of Sagittaria
montevidensis from the Palo Pintado Formation (upper Miocene) in the south of Salta Province, Argentina. Achenes
are laterally compressed, have a lateral beak and a single recurved seed inside them. The fruits were found both in the
base (10 Ma) and the top of the formation (~5 Ma), suggesting similar environmental conditions during this time period.
A cursory review of the Alismataceae family in the fossil record, with a special interest in those South American reports
is given. During the Oligocene–Miocene Sagittaria may have arrived from tropical Africa to South America and thence
to North America.
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.
M. Martínez de Pinillos, Laura Martín‐Francés, J. M. B. de Castro
et al.
Here, we present a metric and morphological study of the molar remains from the Montmaurin-La Niche mandible by means of microcomputed tomography. According to the last analysis, based on the combination of geomorphological and paleontological data, the level bearing this human mandible probably corresponds to the marine isotope stages (MIS) 7. These data place the Montmaurin-La Niche in a chronologically intermediate position between the Neanderthals and the Middle Pleistocene fossils (e.g., Sima de los Huesos, la Caune de l'Arago). A recent study has revealed that while the mandible is more closely related to the Early and Middle Pleistocene African and Eurasian populations, the morphology of the outer enamel surfaces of its molars is typical of the Neanderthal linage. The data presented here are in line with this finding because the morphology of the enamel-dentine junction of the molars is similar to that of Neanderthals, whereas the absolute and relative enamel thickness values (2D and 3D) are closer to those exhibited by some Early Pleistocene hominins. Moreover, the pulp cavity morphology and proportions are in concordance with the Neanderthal populations. Our results strengthen the hypothesis that the settlement of Europe could be the result of several migrations, at different times, originated from a common source population. Thus, the variability in the European Middle Pleistocene populations (e.g., Montmaurin, Sima de los Huesos, Arago, Mala Balanica) could indicate different migrations at different times and/or population fragmentation, without excluding the possible hybridization between residents and new settlers.
Channel Island National Park (CHIS), incorporating five islands off the coast of southern California (Anacapa Island, San Miguel Island, Santa Barbara Island, Santa Cruz Island, and Santa Rosa Island), has an outstanding paleontological record. The park has significant fossils dating from the Late Cretaceous to the Holocene, representing organisms of the sea, the land, and the air. Highlights include: the famous pygmy mammoths that inhabited the conjoined northern islands during the late Pleistocene; the best fossil avifauna of any National Park Service (NPS) unit; intertwined paleontological and cultural records extending into the latest Pleistocene, including Arlington Man, the oldest well-dated human known from North America; calichified “fossil forests”; records of Miocene desmostylians and sirenians, unusual sea mammals; abundant Pleistocene mollusks illustrating changes in sea level and ocean temperature; one of the most thoroughly studied records of microfossils in the NPS; and type specimens for 23 fossil taxa. Paleontological research on the islands of CHIS began in the second half of the 19th century. The first discovery of a mammoth specimen was reported in 1873. Research can be divided into four periods: 1) the few early reports from the 19th century; 2) a sustained burst of activity in the 1920s and 1930s; 3) a second burst from the 1950s into the 1970s; and 4) the modern period of activity, symbolically opened with the 1994 discovery of a nearly complete pygmy mammoth skeleton on Santa Rosa Island. The work associated with this paleontological resource inventory may be considered the beginning of a fifth period. Fossils were specifically mentioned in the 1938 proclamation establishing what was then Channel Islands National Monument, making CHIS one of 18 NPS areas for which paleontological resources are referenced in the enabling legislation. Each of the five islands of CHIS has distinct paleontological and geological records, each has some kind of fossil resources, and almost all of the sedimentary formations on the islands are fossiliferous within CHIS. Anacapa Island and Santa Barbara Island, the two smallest islands, are primarily composed of Miocene volcanic rocks interfingered with small quantities of sedimentary rock and covered with a veneer of Quaternary sediments. Santa Barbara stands apart from Anacapa because it was never part of Santarosae, the landmass that existed at times in the Pleistocene when sea level was low enough that the four northern islands were connected. San Miguel Island, Santa Cruz Island, and Santa Rosa Island have more complex geologic histories. Of these three islands, San Miguel Island has relatively simple geologic structure and few formations. Santa Cruz Island has the most varied geology of the islands, as well as the longest rock record exposed at the surface, beginning with Jurassic metamorphic and intrusive igneous rocks. The Channel Islands have been uplifted and faulted in a complex 20-million-year-long geologic episode tied to the collision of the North American and Pacific Places, the initiation of the San Andreas fault system, and the 90° clockwise rotation of the Transverse Ranges, of which the northern Channel Islands are the westernmost part. Widespread volcanic activity from about 19 to 14 million years ago is evidenced by the igneous rocks found on each island.
Anhanguerids are a particular group of pterodactyloid pterosaurs, characterized mainly by their rostral sagittal crests, well laterally expanded jaw tips and enlarged anterior teeth. Due to the fragmentary nature of most known specimens, including holotypes, the taxonomy of the group has proved particularly difficult and controversial. Coloborhynchinae is a recently proposed clade within the Anhangueridae, and was defined as the most inclusive clade containing Coloborhynchus clavirostris but not Anhanguera or Ludodactylus. Coloborhynchinae was originally thought to include Coloborhynchus, Uktenadactylus, and Siroccopteryx. Here we present a reassessment of the taxonomy and phylogeny of all proposed members of the Coloborhynchinae and Coloborhynchus complex, with new anatomical comparisons and a novel phylogenetic analysis. Several features allow us to establish that coloborhynchines were much more diverse than previously thought, englobing four genera and seven species: Aerodraco sedgwickii gen. et comb. nov., Coloborhynchus clavirostris, Nicorhynchus capito gen. et comb. nov., Nicorhynchus fluviferox gen. et comb. nov., Uktenadactylus rodriguesae sp. nov., and Uktenadactylus wadleighi. Nicorhynchus and Uktenadactylus are considered sister taxa, being distinct on the basis of several rostral characters. Although with a homoplastic flat rostrum surface, Siroccopteryx was recovered out of the Coloborhynchinae, as sister taxon of Tropeognathus, due to similarities on the palatal ridge (which is broad and deep, and starting at the same level) and the relatively stout teeth compared to other anhanguerids. Tropeognathus and Siroccopteryx are further related to the Australian taxa Ferrodraco and Mythunga, which are all grouped in a new clade: the Tropeognathinae. Our analysis suggests that morphological evolution within anhanguerids was quite more complex than previously thought, with coloborhynchines representing the oldest recorded lineage of Anhangueridae, which achieved a worldwide distribution at least from the Aptian to the Cenomanian.
The shape of dermal armor protecting the body in the Paleozoic agnathans such as the Heterostaci has an important hydrodynamic role in providing lift or drag force generation. Here, by performing computational fluid dynamics simulations (CFD), the measurements of hydrodynamic lift/drag force and lift or drag coefficients were taken for two psammosteids Guerichosteus and Tartuosteus with reference to the pteraspid Errivaspis. This study shows the substantially higher values of the lift coefficient and lift-to-drag ratio for the psammosteids Guerichosteus and Tartuosteus compared with Errivaspis. The tendencies in the evolution of dermal exoskeleton, especially the widening of the branchial plates of psammosteids was directed towards the increased generation of lift force to provide efficient cruising.
Coralline algae were widespread in shallow-water environments during the middle Miocene in the central Paratethys. Their distribution and diversity patterns are useful in paleoenvironmental and paleoclimatic studies providing that species identifications are accurate and robust. Taxonomy of fossil coralline algae was traditionally based on morphology of bi/tetrasporophytes whereas taxonomy of extant species is additionally supported by characters that can be observed in the remaining life cycle phases. Therefore, investigations of such characters in fossil record are also essential to avoid misidentifications of ancient coralline algae. Here, I analyse morphology of reproductive phases in subfamilies Hydrolithoideae and Mastophoroideae from the middle Miocene of the central Paratethys. Analyses of published and newly collected hydrolithoid and mastophoroid coralline algae allow: (i) identification of three species of the genus Hydrolithon and two species of the genus Lithoporella; (ii) description of complete life cycle phases for extinct Hydrolithon lemoinei, H. corculumis, and Hydrolithon sp. 1 and (iii) description of incomplete life cycles for Lithoporella minus and Lithoporella sp. 1. The results also prove that characters associated with trichocytes can be used in some fossil coralline algae, and bi/tetrasporic pore canal anatomy is reliable diagnostic character also for fossil species, as it is used in extant coralline algae of the order Corallinales.
Human paleontologists are unable to extricate species-level variation from individual, sexual, regional, geographical, pathological, and skull bone variations despite sophisticated statistical methodology. Additionally, true variation within and between groups cannot be generated from a handful of regional and geographical specimens presently used in comparative studies. I therefore conclude that we cannot identify species in the human paleontological record. This conclusion is supported by the analysis and discussion (in this paper) of research conducted on, what I deem to be, three high-profile genus Homo fossil discoveries: Dmanisi hominins, Homo floresiensis, and Homo naledi. The data compiled in these comprehensive studies conclude that Dmanisi, floresiensis, and naledi share features with all Homo and Australopithecine taxa. Specifically, none of these three fossils clustered or aligned definitively with any Homo specimens. Consequently, it may now be prudent for us to use numbers or look for gross similarities and differences in hominin fossils to classify them. As such, identifying fossils at the genus level, which was proposed recently, might be a solution worth considering. Using genera will reduce the specificity needed in species identification, but it might be preferable to the chaos we have now in species-level identification. This paper is published in two parts.