The two extant Salamandrina species represent a unique case of morphology, ecology, and ethology among urodeles. The range of this genus is currently limited to Italy, where it represents the only ...endemic vertebrate genus, but its past range extended over a much broader area of Europe, including the Iberian and Balkan peninsulas. ENM analyses using modern occurrences of Salamandrina demonstrate that the current climate of the majority of Europe, and especially areas where fossils of this genus were found, is currently not suitable for this genus, neither was it suitable during the last 3.3 million years. This result allows possible assumptions about the climatic influence on the former extirpation of this salamander from several areas of Europe. Furthermore, it shows that, during Pliocene-Pleistocene climatic oscillations, Mediterranean peninsulas, despite being generally considered together because of similar latitude, had different potential to effectively become glacial refugia for this salamander, and possibly for other species as well. Future projections using different CO
emission scenarios predict that climatic suitability will be even more drastically reduced during the next 50 years, underlining once more the importance of conservation strategies and emission-reducing policies.
One of the main explanations for the stunning diversity of teleost fishes (approximately 29,000 species, nearly half of all vertebrates) is that a fish-specific whole-genome duplication event (FSGD) ...in the ancestor to teleosts triggered their subsequent radiation. However, one critical assumption of this hypothesis, that diversification rates in teleosts increased soon after the acquisition of a duplicated genome, has never been tested.
Here we show that one of three major diversification rate shifts within ray-finned fishes occurred at the base of the teleost radiation, as predicted by the FSGD hypothesis. We also find evidence for two rate increases that are much younger than the inferred age of the FSGD: one in the common ancestor of most ostariophysan fishes, and a second one in the common ancestor of percomorphs. The biodiversity contained within these two clades accounts for more than 88% of living fish species.
Teleosts diversified explosively in their early history and this burst of diversification may have been caused by genome duplication. However, the FSGD itself may be responsible for a little over 10% of living teleost biodiversity. ~88% of species diversity is derived from two relatively recent radiations of freshwater and marine fishes where genome duplication is not suspected. Genome duplications are a common event on the tree of life and have been implicated in the diversification of major clades like flowering plants, vertebrates, and gnathostomes. However our results suggest that the causes of diversification in large clades are likely to be complex and not easily ascribed to a single event, even a dramatic one such as a whole genome duplication.
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•We generated a phylogenetic hypothesis of carangoid fishes using 7 genes.•We time-calibrated the molecular phylogeny using several fossil calibrations.•This study supports the ...non-monophyly of carangids without the inclusion of Echeneoidei.•Three of the traditional carangid subfamilies are recovered as monophyletic.•Several carangoid lineages originated in the Late Cretaceous and survived the K-Pg extinction to radiate during the Eocene.
Carangoid fishes (trevallies, pompanos, jacks, dolphinfishes, cobias and remoras) include about 159 species of marine fishes found in tropical and temperate waters worldwide (Froese and Pauly, 2014). Many carangoids are powerful swimmers and active piscivores in and around coral-reef ecosystems. Some carangoid lineages, such as dolphinfishes, have evolved a pelagic lifestyle, while remoras spend their adult life attached to cetaceans, sharks, manta rays and large teleosts, feeding off skin parasites or leftovers from their host’s meals. In spite of their taxonomic diversity, ecological dominance, economic importance to humans, and a rich fossil record dating to the Paleogene, relatively little is currently known about the tempo of evolution of this group. Here we present the results of the first time calibration study of carangoid fishes. Using a fossil-calibrated molecular timetree that includes 133 species of carangoids (∼85% of extant species), we show that this group originated in the Late Cretaceous and that several major lineages were already present before the K-Pg extinction. All major clades were in existence by the end of the Eocene, even though significant diversification has continued to occur throughout the history of this group.
Clupeid fishes are abundant in the Eocene fossiliferous limestone of Monte Bolca, representing by far the most common group from this celebrated locality. However, despite of their abundance, the ...clupeid fishes from Monte Bolca have seldom been investigated. An analysis of about 300 well-preserved clupeid specimens from Monte Bolca housed in several institutions clearly indicates that more than 95% of the available material belongs to different developmental stages of a single taxon, traditionally referred to as †Clupea catopygoptera Woodward. †Bolcaichthys, a new genus of clupeid fish, erected to contain †Clupea catopygoptera Woodward from the Eocene of Monte Bolca, Italy, is described and compared with extant and fossil genera of the family Clupeidae. This new genus shows a unique combination of characters (head length approximately one third to one quarter standard length; skull roof with 10–14 frontoparietal striae; mouth terminal; two supramaxillae; edentulous jaws and palate; complete series of about 20–22 abdominal keeled scutes with ascending arms; no dorsal scutes; five or six branchiostegal rays; eight supraneurals; 40–42 vertebrae and 20–22 pleural ribs; three epurals) supporting its recognition as a new genus of the family Clupeidae. Paleobiological considerations suggest that the presence of a very large number of schooling clupeids belonging to the genus †Bolcaichthys at all stages of development (larval, juvenile, and adult) support the hypothesis that the sediments were deposited close to the coast in a context subject to the ecological influence of the open sea.
A review of the morphological patterns exhibited by all the main radiations of mysticete (baleen whale) cetaceans provided a broad assessment of the fundamental morphological transformations that ...occurred in the transition to the Mysticeti clade. Skull and postcranial characters were illustrated, described and compared, and their distribution was mapped on a combined phylogeny in the search for morphological support for the principal mysticete clades (i.e., Mysticeti, Chaeomysticeti and Balaenomorpha). In particular, characters of the skull (rostrum, vertex, temporal fossa, tympanic bulla and dentary) and the postcranial appendicular skeleton (scapula, humerus, radius and ulna) were all involved at different degrees in the process of morphological transformations leading to the modern-day mysticetes. Apart from a few typical characteristics of the rostrum that were already present in the earliest-diverging mysticetes (presence of lateral process of the maxilla, presence of multiple dorsal infraorbital foramina, thin lateral border of maxilla and presence of mesorostral groove), most of the other anatomical districts were unaffected by the transition so the earliest mysticetes show a number of archaeocete characters in the tympanic bulla, dentary and skull roof. The analysis of the whole dataset supported the hypothesis that the origin and evolution of mysticetes constituted a step-wise process and that the bauplan of the modern-day mysticetes was fully assembled at the level of the common ancestor of all Balaenomorpha.
The uneven distribution of species richness is a fundamental and unexplained pattern of vertebrate biodiversity. Although species richness in groups like mammals, birds, or teleost fishes is often ...attributed to accelerated cladogenesis, we lack a quantitative conceptual framework for identifying and comparing the exceptional changes of tempo in vertebrate evolutionary history. We develop MEDUSA, a stepwise approach based upon the Akaike information criterion for detecting multiple shifts in birth and death rates on an incompletely resolved phytogeny. We apply MEDUSA incompletely to a diversity tree summarizing both evolutionary relationships and species richness of 44 major clades of jawed vertebrates. We identify 9 major changes in the tempo of gnathostome diversification; the most significant of these lies at the base of a clade that includes most of the coral-reef associated fishes as well as cichlids and perches. Rate increases also underlie several well recognized tetrapod radiations, including most modern birds, lizards and snakes, ostariophysan fishes, and most eutherian mammals. In addition, we find that large sections of the vertebrate tree exhibit nearly equal rates of origination and extinction, providing some of the first evidence from molecular data for the importance of faunal turnover in shaping biodiversity. Together, these results reveal living vertebrate biodiversity to be the product of volatile turnover punctuated by 6 accelerations responsible for >85% of all species as well as 3 slowdowns that have produced "living fossils." In addition, by revealing the timing of the exceptional pulses of vertebrate diversification as well as the clades that experience them, our diversity tree provides a framework for evaluating particular causal hypotheses of vertebrate radiations.
A new periotic (MuMAB 240508) is described from the Tortonian of the Stirone River, Northern Italy. The new specimen is described and compared to all the known periotics of extant and extinct ...balaenopterid species. The new specimen shows balaenopterid characters, including the triangular anterior process, the transverse and anteroposterior elongations of the pars cochlearis, as well as in the arrangement of the endocranial foramina of the periotic. The presence of a medial promontorial groove, a lack of separation between the round window and the perilymphatic foramen together with the presence of a protruding set of medial crests suggest that this periotic may belong to an archaic and undescribed balaenopterid species. A phylogenetic analysis was performed to understand the relationships of this specimen within the broader context of balaenopterid phylogeny; this analysis showed that MuMAB 240508 belongs to a basal balaenopterid taxon that is the sister group to all the other Balaenopteridae with the exception of
‘Balaenoptera’ ryani
. An ordinary least squares regression analysis showed that a relationship exists linking the length of the anterior process of the periotic and the total body length in Balaenopteridae. By means of such a relationship, the total body length of the individual to which MuMAB 240508 belonged to was reconstructed and resulted in
c.
14.4 m. This individual was longer than all the other contemporaneous balaenopterid mysticetes confiming the hypothesis that the origin of large size occurred in this family earlier than previously thought.
The clupeomorph fish Gasteroclupea branisai Signeux, 1964 from the Late Cretaceous-Paleocene of El Molino Formation, Cayara locality, Bolivia is redescribed in detail. This South American ...double-armored herring is the sole member of the family Gasteroclupeidae and exhibits a unique combination of features (skull roof ornamented with fine tubercles, beryciform foramen, endopterygoid teeth, about 16-18 supraneurals, a series of 35-38 predorsal and 40 ventral scutes, median fins small and containing 12-14 rays) that clearly supports its assignment to the extinct clupeomorph order Ellimmichthyiformes. G. branisai shares a number of synapomorphies with Sorbinichthys elusivo and S. africanus (five hypurals, second hypural autogenous, distal end of the second uroneural not reaching the distal end of the first uroneural) with which it forms a monophyletic assemblage recognized herein for the first time as the new suborder Sorbinichthyoidei. The peculiar morphology of Gasteroclupea that is characterized by having an extremely deep abdominal profile, hypertrophied coracoid, and elongated pectoral fins, resembles in many aspects the body plan of extant freshwater hatchetfishes of the characiform family Gasteropelecidae, suggesting that the morphological adaptations of G. branisai can be related, at least in part, to a similar lifestyle.
We provide a new study of previously published eurhinodelphinid materials from the early Miocene of Piedmont (NW Italy) based on a new preparation of the fossil specimens. We studied specimens ...previously assigned to Tursiops miocaenus and Dalpiazella sp. and provide new anatomical data on the eurhinodelphinid skull and ear bones. In particular, we suggest that a skull that was previously assigned to Tursiops miocaenus must be reassigned to Ziphiodelphis sigmoideus (Cetacea, Odontoceti, Eurhinodelphinidae) based on new comparisons of the squamosal. This finding enabled us to provide new anatomical information on the ear bone anatomy of Z. sigmoideus that was previously unknown. The material originally assigned to Tursiops miocaenus is currently lost. For this reason and due to the fact that the partial illustration of this species by Portis does not allow us to find diagnostic characters for this species, we decided that Tursiops miocaenus is a nomen dubium. Analysis of additional isolated teeth previously assigned to Tursiops miocaenus led to the conclusion that these specimens represent Odontoceti incertae sedis. We performed a new phylogenetic analysis by adding newly discovered character states to a previous dataset and a paleobiogeographic analysis of Eurhinodelphinidae. We found two monophyletic clades within this family. The paleobiogeographic pattern found by the present work suggests the existence of North Atlantic and Mediterranean clades with some species distributed among both basins. We analyzed the virtual endocast of Ziphiodelphis sigmoideus and found that it resembles that of Schizodelphis in several respects, suggesting that some of the more derived characters of the odontocete brain were still absent in these early Miocene eurhinodelphinids.
Cercopithecid fossil remains from the post-evaporitic Messinian (5.40–5.33 Ma, MN13, latest Turolian, latest Miocene) locality of Moncucco Torinese (Tertiary Piedmont Basin, NW Italy) are described. ...A talus is assigned to the fossil colobine Mesopithecus pentelicus, while a proximal fragment of ulna and a male lower canine are attributed to cf. Me. pentelicus. An isolated I2 and M3 are assigned to the papionin cf. Macaca sp., and two cercopithecid phalanges are left unassigned even to the subfamily level. The record of Mesopithecus at Moncucco Torinese agrees well with the previously-known range of this species in Italy and elsewhere in Europe, whereas that of cf. Macaca constitutes only the second occurrence of macaques in the Miocene of Eurasia. Although the co-occurrence of these two genera in a single locality had been previously reported in the Pliocene, this is the first instance in which macaques are associated with the Late Miocene M. pentelicus instead of Mesopithecus monspessulanus. The record of cf. Macaca and Mesopithecus—and especially the latter's talar morphology, similar to that of extant arboreal colobines—fits well with paleoenvironmental reconstructions of Moncucco Torinese based on the associated fauna, which indicate a humid and densely-forested environment, probably with more open and drier habitats nearby. From a paleobiogeographic viewpoint, the record of Macaca at Moncucco Torinese, together with the previously reported occurrence at Almenara–Casablanca M (Spain), supports the contention that macaques dispersed from Africa into Europe during the latest Miocene (ca. 5.9–5.3 Ma) at the same time as the sea level drop associated with the Messinian Salinity Crisis.
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