Extant Fauna Research Articles

Seed dispersal of Madagascar's iconic baobab species, Adansonia grandidieri

AbstractCertain plant species have traits adapted for seed dispersal by megafauna, which may be absent in their current ranges. Characterizing the dispersal mechanism of such plant species can provide insights about their population dynamics and regeneration. We investigated the effectiveness of the extant fauna as seed dispersers of the Malagasy baobab, Adansonia grandidieri, which have megafaunal dispersal traits. We documented the animal species that interact with its fruits and seeds in the canopy and on the ground through direct observations, camera trapping, opportunistic search of feces with seeds, and dispersal experiments. We also estimated seed fate using a model parameterized with data obtained through experiments on seed removal and seed germination under and away from adult A. grandidieri trees. Further, we examined the impacts of seed dispersal in mitigating herbivore pressures on A. grandidieri seedling through an exclosure experiment. We did not find animals interacting with fruits in the canopy. However, we observed a native rodent species, Eliurus myoxinus, handling fruits/seeds on the ground, and found seeds in bush pig feces. Also, while the rates of germination for the dispersed A. grandidieri seeds were low, their probability of producing viable seedlings was higher than when the seeds stayed under adult trees. We also found that the seedlings of A. grandidieri had a high probability of surviving even when herbivores were present. Overall, our results provide insights into the regeneration of A. grandidieri and suggest that some extant local ground‐dwelling fauna can provide seed dispersal services to this species.Abstract in Malagasy is available with online material.

Central Argentina vegetation characteristics linked to extinct megafauna and some implications on human populations

In this paper we study the relationships between plants and extinct megafauna by examining the characteristics of the vegetation in the central region of Argentina (i.e. Espinal, Monte, and Chaco phytogeographic regions). First, we study the size, shape, quantity, and characteristics of fruits and seeds. We also evaluate the presence of mechanical (spinescence and wood density) and chemical (secondary metabolic compounds) defenses against high rates of herbivory. Complementarily, we assess the importance these plants had for human populations, using archeological, ethnographic, and current data. A high percentage of the analyzed plants met the criteria proposed for fruits and seeds dispersed by megafauna, together with a high frequency of spinescence, high density woods, and secondary metabolites. We propose that these traits cannot be explained by the herbivory pressure of extant fauna in the area, but rather developed in interaction with currently extinct fauna. We suggest that Pleistocene megafaunal extinction had important consequences in the region due to their role as ecosystem engineers and to vegetation’s characteristics, which were probably strongly shaped by megafauna activities. Among these consequences, we discuss the loss of certain interactions between these animals and vegetation, such as loss of seed dispersal mechanisms, shrub invasion, and increased susceptibility of vegetation to fire. Other effects for hunter-gatherer groups were the generation of highly regulated mobility patterns and the formation of barriers for the dispersal of prey. Finally, we also discuss the importance of these plants for human populations as food, construction material, medicines and firewood. Likewise, the role of humans as “heirs” of the megafauna in the propagation of tree and shrub species is highlighted.

Two new species of Tasiocera Skuse from Baltic amber (Diptera, Limoniidae)

The paper presents very rare fossil record of crane flies. Inclusions in Baltic amber have documented the second evidence of the existence of the genus Tasiocera (Diptera: Limoniidae: Chioneinae) in ancient epochs of Earth’s history. Hypotheses were also introduced regarding the environmental preferences of fossil Dasymolopilus in relation to modern representatives of the subgenus. The genus is numerous in species and widespread in the modern fauna, while only one species, Tasiocera (Dasymolophilus) circumcincta, has been known from the fossil record to date. The paper presents an additional description and graphic documentation of this species based on new materials. The discovery of two other species Tasiocera (Dasymolophilus) gorskii sp. nov. and Tasiocera (Dasymolophilus) baltica sp. nov. in Eocene resins documents the occurence of Tasiocera since Eocene. Interestingly, only subgenus Dasymolophilus is represented both in extinct and extant fauna while subgenus Tasiocera is not known from the fossil record. The new discovery is very significant, and the result of the study adds a brick to our understanding of the evolution of this group of insects and their habitat.

The first Paleogene record of Hyperisus Mulsant and Rey (Coleoptera: Ptinidae) with description of a new species and an attempt of biogeographic analysis of ptinid assemblage in Baltic amber

ABSTRACT Based on an inclusion in Baltic amber, the first extinct species of the genus Hyperisus Mulsant and Rey, 1863 (Ptinidae: Ernobiinae: Xestobiini), namely H. carstengroehni sp. nov. is described. This new fossil Eocene species differs from extant European congeners in having the dorsal pubescence of two types; the lesser body size; the abdominal ventrite 5 punctate; the dorsal pubescence evenly dense; the antennal club longer than antennomeres 1–8 combined; and in the details of dorsal punctation. Provisional biogeographical affinities of the described Baltic amber Ptinidae (as of July 2023) are briefly analysed. All 20 extant genera known in Baltic amber (100% of analysed assemblage) still inhabit Holarctic of Recent. The ptinid assemblage of Baltic amber is almost twice closer in the composition of genera to the extant fauna of Palearctic or Nearctic than to other regions. Possible explanations are proposed for the abundance of death-watch beetles in Baltic amber.

The Diversity of Larvae with Multi-Toothed Stylets from About 100 Million Years Ago Illuminates the Early Diversification of Antlion-like Lacewings

Neuroptera, the group of lacewings, is well known to have been more diverse in the past, offering to study patterns of biodiversity loss over time. This loss of diversity has been quantitatively established by the morphological diversity of lacewing larvae. Here, we explore in more detail the diversity of lacewing larvae with tooth-bearing mouthparts. All these larvae are representatives of Myrmeleontiformia, the group of antlion-like lacewings. Today, larvae of several major ingroups bear teeth on their mouthparts: (1) owllions (formerly Ascalaphidae and Myrmeleontidae; taxonomic status is currently unclear); (2) Nymphidae; (3) Crocinae (mostly in younger larvae); and (4) Nemopterinae (only micro teeth). In addition, there are several now extinct larval types with teeth known from Cretaceous ambers (about 100 million years old). These larvae also possess several plesiomorphic characters, indicating that they were part of the early diversification of Myrmeleontiformia. We report numerous new specimens of these now extinct forms and provide a quantitative morphological comparison of head and mouthpart shapes, demonstrating that some of these Cretaceous larvae possessed morphologies not represented in the extant fauna. The resulting pattern is complex, indicating that at least some extinct morphologies have been later replaced by modern-day antlions due to convergent evolution.

Turtles in trouble. Conservation ecology and priorities for Australian freshwater turtles

AbstractThe Australian freshwater turtle fauna is dominated by species in the family Chelidae. The extant fauna comprises a series of distinct lineages, each of considerable antiquity, relicts of a more extensive and perhaps diverse fauna that existed when wetter climes prevailed. Several phylogenetically distinctive species are restricted to single, often small, drainage basins, which presents challenges for their conservation. Specific threats include water resource development, which alters the magnitude, frequency, and timing of flows and converts lentic to lotic habitat via dams and weirs, fragmentation of habitat, sedimentation, nutrification, and a reduction in the frequency and extent of floodplain flooding. Drainage of wetlands and altered land use are of particular concern for some species that are now very restricted in range and critically endangered. The introduced European red fox is a devastatingly efficient predator of turtle nests and can have a major impact on recruitment. In the north, species such as the northern snake‐necked turtle are heavily depredated by feral pigs. Other invasive animals and aquatic weeds dramatically alter freshwater habitats, with consequential impacts on freshwater turtles. Novel pathogens such as viruses have brought at least one species to the brink of extinction. Species that routinely migrate across land are impacted by structural simplification of habitat, reduction in availability of terrestrial refugia, fencing (including conservation fencing), and in some areas, by high levels of road mortality. We report on the listing process and challenges for listing freshwater turtles under the Australian Environment Protection and Biodiversity Conservation Act, summarize the state of knowledge relevant to listing decisions, identify the key threatening processes impacting turtles, and identify key knowledge gaps that impede the setting of priorities. We also focus on how to best incorporate First Nations Knowledge into decisions on listing and discuss opportunities to engage Indigenous communities in on‐ground work to achieve conservation outcomes.

New records of assassin bugs (Hemiptera: Heteroptera: Reduviidae) for the Dominican Republic

The Hispaniolan fauna of Reduviidae is only partially known, as it has never been the subject of a comprehensive taxonomic or faunistic inventory. These species belong to Neotropical genera that have Caribbean, Central and South American distributions. In this contribution new records are given for 14 species of assassin bugs belonging to six subfamilies. Among these, seven species are first records from the Dominican Republic and the island of Hispaniola: Bactrodes spinulosus Stål, 1862 (Bactrodinae), Lophoscutus rideri Kormilev, 1988, Lophoscutus rugosipes (Guérin-Méneville, 1857) both belonging to Phymatinae, Leogorrus pallipes Stål, 1872 (Reduviinae), and the Saicinae species Oncerotrachelus nasutus (Bergroth, 1913), Tagalis drakkar Varela & Melo, 2017 and Tagalis grossi Gil-Santana, 2011. With these new records the reported extant fauna of Hispaniolan Reduviidae reaches a total of 46 documented species, which are classified in 25 genera and 10 subfamilies. Additionally, 13 fossil species have been reported from the Dominican amber.

Paraphloeostiba dominicana sp. nov.: The first omaliine rove beetle from Dominican amber (Coleoptera: Staphylinidae: Omaliinae)

Paraphloeostiba dominicana Shavrin & Jenkins Shaw, sp. nov. from mid-Miocene Dominican amber is described and illustrated. It represents the first species of the rove beetle subfamily Omaliinae from this Neotropical fossil deposit and represents a genus that is not known among the extant fauna of the Neotropics. The new species, embedded within a large piece of amber, was scanned using X-ray micro-computed tomography (μCT), to enable the study of its morphology, including the male genitalia (aedeagus). Based on the revealed characters, the new species is compared with extant and extinct species of the genus Paraphloeostiba Steel, 1960 whose wide extant distribution is confined to the (sub)tropical zones of the world except the Neotropical region and whose fossil record is otherwise known from two species preserved in Eocene Baltic amber from Denmark and Russia. The systematic placement of the genus within the tribe Omaliini, its current and historical ecology and biogeography, as well as the probability that it will be found in the recent Neotropical fauna among the unrevised and undescribed species of Omaliinae are discussed.

Expanding the Fossil Record of Soldier Fly Larvae—An Important Component of the Cretaceous Amber Forest

Larvae of soldier flies and their closest relatives (Diptera: Stratiomyomorpha) are important decomposers of organic material, including wood, that take part in carbon cycling. They also play a certain role in the modern-day animal and human food industry, representing economic value. Larvae of Stratiomyomorpha are considered to be rather rare in the fossil record. Indeed, only very few larvae have been reported so far. Here, we demonstrate that larvae of Stratiomyomorpha are in fact abundant in the Cretaceous, at least in Myanmar amber (about 100 million years old), based on more than 100 amber pieces containing larvae. The specimens could be differentiated into three morphotypes, two already described in a previous work, and a new one. For one morphotype, three larval stages could be distinguished by analysing the dimensions of the head capsules. A quantitative analysis of body shapes indicates a lower morphological diversity of the fossil sample in comparison to the extant fauna, but suggests that they might have had a different ecology in the past. It appears that the data set is not yet saturated, i.e., that more fossil larvae of this group, including different morphologies, are expected to be found.

A new tribe, genus and species of the tenebrionid subfamily Lagriinae (Coleoptera: Tenebrionidae) from the Eocene Baltic amber.

A new genus and species are described from the Eocene Baltic amber: Archaeoluprops groehni gen. et sp. nov. This fossil darkling beetle of the subfamily Lagriinae (Tenebrionidae) is externally similar to species of the tribes Lupropini and Goniaderini having the robust pubescent body and estriate elytra, but differs in the absence of intersegmental membranes between abdominal ventrites 3-5 (tentyrioid hinging) and accordingly the primary absence of defensive glands. Combination of plesiomorphic and apomorphic characters and other differences from all extinct and extant lagriine tribes allows to establish the new tribe Archaeolupropini trib. nov. (type genus Archaeoluprops), which is probably a basal group in relation to the non-basal clade Lagriini-Chaerodini-Lupropini-Pycnocerini-Goniaderini-(probably Gonialaenini) + Laenini. All Baltic amber lagriine tribes are absent in extant faunas of middle latitudes of Europa.

An enigmatic beetle with affinity to Lamingtoniidae in mid-Cretaceous amber from northern Myanmar (Coleoptera: Cucujoidea)

An enigmatic cucujiform beetle, Alloterocucus atratus Li, Leschen, Liu, and Cai gen. et sp. nov., is reported from mid-Cretaceous Burmese amber. The character combination of the new fossil is not completely consistent with any of the known cucujoid or erotyloid families. Based on our phylogenetic analyses, Alloterocucus is assigned to Cucujoidea and may be allied to Lamingtoniidae, which contains a single Australasian genus in the extant fauna. Alloterocucus shares with Lamingtoniidae a similar habitus and a series of characters, including the absence of postocular constriction, 3-segmented antennal club, externally open procoxal cavities, laterally open mesocoxal cavities, exposed pro- and mesotrochantins, and the absence of epipleural fovea and pronotal setose cavities, but differs from extant Lamingtoniidae in its apically truncate terminal maxillary palpomeres, 5-5-4 tarsi in male and absence of distinct dorsal punctation.Zoobank registration[https://zoobank.org/], identifier [111CE15E-5B49-4154-9E4A-7B3A738C6D2A].

The earliest known species of Permeca (Insecta, Mecoptera, Permochoristidae) from the late Guadalupian Yinping Formation of China

Mecoptera are commonly known as scorpionflies, as some mecopterans have bulbous genitals that are upturned, resembling the stinger of scorpions. As one of the most ancient holometabolous orders (Kristensen, 1981; Dunford & Somma, 2008), the stem group of mecopterans can be dated back to the early Permian (Rasnitsyn, 2004). Mecopterans play an important role in our understanding of the origin of fleas. Some Mesozoic giant fleas have been suggested to be derived from extinct long-proboscid mecopterans (Huang et al., 2012), and recent phylogenomic evidence has clearly demonstrated that fleas are nested within Mecoptera (Tihelka et al., 2020). Mecoptera are very abundant in the geological past, with more than 700 species and 210 genera placed in 39 families (Novokshonov et al., 2016; Ren et al., 2019; Wang, 2020). Extant faunas are represented by ca. 700 species and 40 genera assigned to 9 families (Bicha, 2018; Wang, 2020).

The Morphological Diversity of Antlion Larvae and Their Closest Relatives over 100 Million Years.

Simple SummaryThe larvae of owlflies and antlions (here shortly embraced by the term “owllions”) are ambush predators. Their mouthparts are transformed into teeth-bearing stylets and used for catching prey and sucking, which is characteristic for neuropteran larvae. Here we used the morphology of the stylets and the head capsules of a large number of extant and fossil larvae as a proxy for the morphological diversity over time. The created dataset comprises outlines of stylets and head capsules of specimens from the literature, collections, databases and the herein described and depicted 38 fossil ones. Fossils in the whole dataset come from deposits with an age of about 20, 40, and 100 million years (Miocene, Eocene, and Cretaceous, respectively). In addition to the shape analysis of the outlines from the dataset, we conducted a statistical analysis as well. Eocene and Miocene samples did not result in a clear output, but Cretaceous samples allowed for some conclusions: The morphological diversity of owllion larvae increased over time, even though some morphologies of Cretaceous larvae went extinct.Among lacewings (Neuroptera), representatives of the groups Ascalaphidae (owlflies) and Myrmeleontidae (antlions) are likely the most widely known ones. The exact taxonomic status of the two groups remains currently unclear, each may in fact be nested in the other group. Herein, we refer to the group including representatives of both with the neutral term “owllion”. Owllion larvae are voracious ambush hunters. They are not only known in the extant fauna, but also from the fossil record. We report here new findings of a fossil owlfly larva from Eocene Baltic amber, as well as several owlfly-like larvae from Cretaceous Kachin amber, Myanmar. Based on these fossils, combined with numerous fossil and extant specimens from the literature, collections, and databases, we compared the morphological diversity of the head and mouthpart shapes of the larvae of owllions in the extant fauna with that of owllion-like larvae from three time slices: about 100 million years ago (Cretaceous), about 40 million years ago (Eocene), and about 20 million years ago (Miocene). The comparison reveals that the samples from the Eocene and Miocene are too small for a reliable evaluation. Yet, the Cretaceous larvae allow for some conclusions: (1) the larval morphological diversity of owllion larvae increased over time, indicating a post-Cretaceous diversification; (2) certain morphologies disappeared after the Cretaceous, most likely representing ecological roles that are no longer present nowadays. In comparison, other closely related lineages, e.g., silky lacewings or split-footed lacewings, underwent more drastic losses after the Cretaceous and no subsequent diversifications.

Late Quaternary land snail faunas of the Desertas Islands (Madeira): high diversity and endemism followed by recent impoverishment and extinction

ABSTRACT Late Quaternary deposits containing fossil snail shells were sampled from nine sites on Deserta Grande and three on Bugio, two of the three Desertas Islands in the oceanic Madeiran archipelago. In total, 3,432 shells representing 45 species or subspecies were retrieved. Calibrated amino acid racemization yielded ages ranging from >45 to 6 ka, with variation by site often confounded by reworking of mostly colluvial deposits. The assemblages found are compared with the extant fauna, itself a subject of intensive recent study. Of the 45 taxa, 18 are apparently extinct, and a further 5 no longer survive on the Desertas. A similar pattern emerges when each island is considered separately. The level of local extinction (c. 50%) is greater than seen on the larger, nearby islands of Madeira and Porto Santo. There are few endemic species in the extant fauna not represented in the fossil assemblages, but there are a number of possibly adventitious species, some with wide distributions in Europe. There is little evidence of faunal change within the limits of the age range available, and extinction seems to be concentrated in the later Holocene. It is attributed to the massive habitat destruction that occurred subsequent to human occupation from the 15th century CE onwards. The study emphasizes the depauperate nature of many extant island faunas subject to human disturbance.

The extant fauna of Neuroptera (Insecta) from Brazil: diversity, distribution and history

This survey presents an overall view of the order Neuroptera from Brazil. A total of 432 valid extant species of Neuroptera divided into ten families, are recorded from the country. Among the Brazilian fauna, 211 species are endemic (48.8%), with the majority belonging to two families: Chrysopidae with 182 species in 19 genera, and Myrmeleontidae with 88 species in 25 genera. The first species discovered from Brazil was Climaciella semihyalina (Le Peletier & Audinet-Serville), in 1825, by European authors. In fact, European authors entirely dominated the description of Brazilian Neuroptera during the 19th century. Father Longinos Navás from Spain authored the highest number of species described from Brazil, 98, followed by US-American Norman Penny, with 83 species. Sérgio de Freitas, a Brazilian researcher, ranks third, with a total of 50 species described. It was not until the 21st century that the study of neuropterans from Brazil was primarily led by Brazilian-born authors. Primary type specimens of species described from Brazil are predominantly deposited in non-Brazilian institutions (65.7%). The order Neuroptera is distributed across all Brazilian states, except for Alagoas. The two states with the highest neuropteran biodiversity are Amazonas and São Paulo, with 132 and 124 species, respectively. Among the Brazilian biomes, the Mata Atlântica is the most diverse region with 227 known species, followed by the Amazônia with 192 species. Data on immature stages of Neuroptera are scarce and known for only 47 species recorded from Brazil (10.9%).

Just a Fragment of Undescribed Diversity: Twenty New Oriental and Palearctic Species of Sciaroidea (Diptera), including DNA Sequence Data and Two New Fossil Genera.

Simple SummaryTwo-winged flies (Diptera) are one of the megadiverse insect orders, in terms of biodiversity. The suborder Nematocera (=lower Diptera) includes several particularly species-rich groups, such as fungus gnats (Mycetophilidae and related families of the superfamily Sciaroidea) and gall midges (Cecidomyiidae), the latter presumably even being the most diverse family of Diptera of all. Although every year dozens of new species from these families are being described, either from extant fauna or from the fossil record, an amazing number of species still remain undescribed, especially outside Europe or North America. In this paper, another portion of new taxa of fungus gnats is described, enabling to better understand the fascinating and still little-known world of insects on Earth.The following 17 extant new species of Sciaroidea (Diptera: Bibionomorpha) are described: Bolitophila nikolae Ševčík sp. nov. (Bolitophilidae, Taiwan), Catocha jingfui sp. nov. (Cecidomyiidae, Taiwan), Catocha manmiaoe sp. nov. (Cecidomyiidae, Taiwan), Catocha shengfengi sp. nov. (Cecidomyiidae, Taiwan), Planetella taiwanensis sp. nov. (Cecidomyiidae, Taiwan), Diadocidia pseudospinusola sp. nov. (Diadocidiidae, Taiwan), Asioditomyia bruneicola sp. nov. (Ditomyiidae, Brunei), Asioditomyia lacii sp. nov. (Ditomyiidae, Taiwan), Ditomyia asiatica sp. nov. (Ditomyiidae, Thailand), Chetoneura davidi sp. nov. (Keroplatidae, Brunei), Euceroplatus mantici sp. nov. (Keroplatidae, Thailand), Setostylus fangshuoi sp. nov. (Keroplatidae, Taiwan), Platyceridion yunfui sp. nov. (Keroplatidae, Hainan), Terocelion adami sp. nov. (Keroplatidae, Taiwan), Hadroneura martini sp. nov. (Mycetophilidae, Taiwan), Paratinia furcata sp. nov. (Mycetophilidae, Czech Republic, Slovakia), and Nepaletricha sikorai sp. nov. (Sciaroidea incertae sedis, Thailand). Two new genera are described from the mid-Cretaceous Burmese amber, Burmasymmerus gen. nov. (Ditomyiidae, type species Burmasymmerus korneliae sp. nov., including also B. wieslawi sp. nov.), representing the first record of the family Ditomyiidae from the Mesozoic, and Burmatricha gen. nov. (Sciaroidea incertae sedis, type species Burmatricha mesozoica sp. nov.). Molecular phylogeny of Ditomyiidae, based on two DNA markers (28S, COI), as well as that of Catocha Haliday, 1833, based on the mitochondrial COI and 16S fragments, are also presented.

A fossil fish assemblage from the middle Miocene of the Cocinetas Basin, northern Colombia

AbstractFreshwater fossil fish faunas have long been used to infer past drainage connections, given that they are bounded by physical freshwater barriers. Here we study a middle Miocene (15.0–15.5 Ma) freshwater fish fossil fauna (Makaraipao) from the Castilletes Formation in northern Colombia, nowadays west of the Andes. We record the presence of lungfishes (Lepidosiren), pacus (Mylossoma and Piaractus), armoured catfishes (Callichthyidae), and red‐tail catfishes (Phractocephalus). Extant members of all those groups (except the Callichthyidae, due to lack of taxonomic resolution) are found in Amazonian faunas east of the Andes and are absent from faunas west of the Andes, indicating that the riverine systems of the Guajira Peninsula were connected to Amazonia during the middle Miocene. The similarity of La Venta (west of the Andes) and Rio Acre (east of the Andes) fish faunas during the late Miocene further indicates that the northern Andean uplift was not a complete barrier at least until c. 11 Ma. However, there is a continental‐wide structuring of the Miocene fish faunas that is also found in the extant faunas, suggesting that other factors such as ecological conditions, in addition to the uplift of the Andes, have shaped the biogeographic evolution of South American fish faunas.

Texas beetle larvae (Brachypsectridae) – the last 100 million years reviewed

Larvae of Brachypsectridae (Texas beetles) have often been considered rare. However, they are known from North America, Asia and Australia in the extant fauna, and from Miocene, Eocene and Cretaceous ambers. We review the overall record of extant and fossil larvae of Brachypsectridae represented in the literature. Furthermore, we present three new specimens, which were all documented via light microscopy. Two of the specimens are from Baltic amber, and the third one is from the Cretaceous amber of Myanmar; the latter was additionally documented via synchrotron radiation micro-computed tomography. The number of known extant specimens, more than 20, is unusually high compared to other small groups of beetles and with respect to the low number of eight formally described species. The number of fossil specimens from the Miocene, Eocene and Cretaceous is low, two to three specimens per time slice. This makes a comparison of morphological diversity difficult. Still such an analysis of overall body shape as well as of the anterior body region revealed no significant quantitatively recognisable changes over time. However, some qualitative changes in the morphology of the antenna and lateral processes from the Cretaceous to younger faunas could be identified.

Bone histology of Broad-snouted Caiman Caiman latirostris (Crocodylia: Alligatoridae) as tool for morphophysiological inferences in Crocodylia

Bone histology is an important tool for the interpretation of life patterns in animals of the past and extant fauna. The crocodylians have been studied as important inferential models for morphophysiological characteristics. We aimed to characterize the osteohistology of captive Caiman latirostris, identifying its microanatomy related to growth rates, ontogeny, and environmental conditions. We analyzed five pairs of humeri (proximal elements of the appendicular skeleton) and ribs (axial skeleton) of females’ caiman. Ribs showed, in general, woven-fibered tissues, with low vascularization and parallel-fibered bone and many resorption and erosion cavities. It presented lines of arrested growth (LAGs) in three individuals, without skeletochronological compatibility. Humeri showed a gradient of woven-fibered to parallel-fibered and lamellar-zonal bone as the individuals aging. We observed compacted coarse cancellous bone (CCCB) and a higher number of LAGs in older specimens. Ribs remodel faster than humerus, showing an intra-individual histovariability. The humeri indicated an evident growth pattern with different ontogeny stages and growth rates in different ages. Fast-growing tissues are uncommon in crocodylians, but basal metabolism and optimal growth conditions can lead to this. Bone histology of C. latirostris shows patterns that can be used as inferential models for extant and extinct groups, but we encourage further studies for a better understanding, under different environmental conditions, such as temperature and food availability.

Early Miocene stalked crinoids (Echinodermata) from the southern Rhodanian basin (southeastern France). Paleoenvironments and taxonomy.

Using recent samplings and specimens from ancient collections, 14 sites and five species of stalked crinoids have been listed in the Miocene of the southern Rhodanian basin (southeastern France). Three species and two genera are new for science: Papacrinus avignonensis n. gen., n sp. (Balanocrininae), Paraconocrinus rhodanicus n. sp. (Rhizocrinidae) and Gastecrinus vinealis n. gen., n. sp. (Incertae sedis). The identification among the Mediterranean Miocene fauna of the genus Metacrinus, now confined to the Indo-Pacific province, was confirmed by the discovery of brachial ossicles attributed to Metacrinus berthei. The richest and most diversified site was exposed during temporal excavations at the Place du Palais des Papes in Avignon. Four out of the five stalked crinoid species were found in this fossil assemblage in which M. berthei predominates. ?Endoxocrinus gastaldii is associated with M. berthei in several sites. Using dissociated ossicles, differences in quantitative and qualitative characters between these two species are deeply analyzed with their taphonomical, taxonomical and paleoecological consequences. Paleoreliefs and valleys, which had been incised during the Burdigalian, channeled currents. They favored stalked crinoid settlement on various substrates during the late BurdigalianLower Langhian transgression. Comparison with the extant fauna allows us to estimate the depth range of the biotopes with stalked crinoids from 100 to 250 m. These estimates are in agreement with those deduced from other paleontological studies.