Palaeoproteomics resolves sloth relationships

The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major xenarthran radiation that occupied a wide range of habitats in many parts of the western hemisphere during the Cenozoic, including both continents and the West Indies. Ancient DNA evidence has played only a minor role in folivoran systematics, as most sloths lived in places not conducive to genomic preservation. Here we utilize collagen sequence information, both separately and in combination with published mitochondrial DNA evidence, to assess the relationships of tree sloths and their extinct relatives. Results from phylogenetic analysis of these datasets differ substantially from morphology-based concepts: Choloepus groups with Mylodontidae, not Megalonychidae; Bradypus and Megalonyx pair together as megatherioids, while monophyletic Antillean sloths may be sister to all other folivorans. Divergence estimates are consistent with fossil evidence for mid-Cenozoic presence of sloths in the West Indies and an early Miocene radiation in South America

New Miocene Caribbean gavialoids and patterns of longirostry in crocodylians

Gavialoidea is a clade of slender- and long-snouted crocodylomorphs with a single living species, the Indian gharial Gavialis gangeticus. Because elongated snouts (longirostry) have evolved independently in several crocodylomorph clades, this head shape has been interpreted as an ecological adaptation. How this condition affected patterns of diversification and how longirostrineassociated cranial features changed through adaptive radiations remain poorly understood. Two new small gryposuchine gavialoids, Dadagavialis gunai gen. et sp. nov. (early Miocene, Panama) and Aktiogavialis caribesi sp. nov. (late Miocene, Venezuela), evidence remarkable Miocene diversification of longirostrine forms in the Neotropics and support transmarine biogeographical relations between northern South America, the Caribbean, and southernmost North America before the Isthmus of Panama was fully established. By integrating phylogenetics and geometric morphometrics, we focus on this gavialoid diversity to investigate patterns of longirostry across the crown group of crocodylomorphs (Crocodylia). Analyses revealed that the snout shape of gavialoids has occupied a small, distinct and almost invariable morphospace since the Cretaceous, in contrast with the morphologically labile snout shape of other crocodylians (crocodyloids and alligatoroids). Our results suggest iterative environmental shift occupations throughout gavialoid evolution without major changes in snout proportions, but involving conspicuous rearrangements of the circumorbital bones. The longirostrine gavialoid morphotype is a distinct adaptation for seizing small prey and typically includes short and wide premaxillae and enlarged ‘caniniform’ teeth only at the tip of the snout. In longirostrine crocodyloids (Tomistoma, Crocodylus intermedius), the conservation of powerful bites and ‘caniniforms’ closer to the jaw joints allowed them to exploit a wider range of prey sizes, which could explain their snout shape plasticity. Therefore, the Mio–Pliocene extirpation of gryposuchine gavialoids from the Caribbean by the arrival of Crocodylus is quite unlikely. The last gryposuchine survived throughout the Pliocene in the south-eastern Pacific, where Crocodylus has never been documented

Cryptophractus pilosus Fitzinger 1856

<i>Cryptophractus pilosus</i> Fitzinger, 1856 [nomen revalidatum] <p> <i>Cryptophractus pilosus</i> Fitzinger, 1856:123. Holotype NMW 222; type locality Peru. <i>Praopus hirsutus</i> Burmeister, 1862:147. Possibly MUSM 27 (see above); type locality “Guayaquil”, Peru. [<i>Tatusia</i> (<i>Cryptophractus</i>)] <i>pilosa</i>: Trouessart, 1898:1140; name combination.</p> <p> [<i>Tatus</i> (<i>Cryptophractus</i>)] <i>pilosus</i>: Trouessart, 1905:814; name combination.</p> <p> <i>Tatu pilosa</i>: Thomas, 1927:605; name combination.</p> <p> <i>Dasypus pilosa</i>: Yepes, 1928:468; name combination with incorrect gender agreement. <i>Dasypus pilosus</i>: Frechkop & Yepes, 1949:27; gender agreement correction.</p> <p> <i>Dasypus</i> (<i>Cryptophractus</i>) <i>pilosus</i>: Talmage & Buchanan, 1954:84; name combination.</p> <p> <b>Holotype.</b> NMW 222, mounted skin (Fitzinger 1856).</p> <p> <b>Type locality.</b> Montane Peru (restricted by Wetzel & Mondolfi 1979).</p> <p> <b>Distribution.</b> Montane cloud forests and subparamo of Peruvian Andes, in the departments of San Martín, La Libertad, Huánuco, Junín, Amazonas (Grimwood 1969; Wetzel & Mondolfi 1979; Wetzel <i>et al.</i> 2007) and expanded herein to Pasco (Fig. 3). The specimens examined were generally collected close to water bodies, between 2,600 to 3,400 m above the sea level.</p> <p> <b>Diagnosis.</b> Dense hair covering the whole carapace, obscuring it; cephalic shield narrow and elongate, loosely delimitated anteriorly, with acute posterior margin more distantly separated from the base of the ears, and V-shaped occipital sulcus; greater number of completely movable bands (9 to 11); osteoderms with no sulci, numerous foramina (more than 30), and frequently two larger foramina placed anteriorly in the movable osteoderms; rostrum and palate longer and narrower (rostral ratio 0.66 on average; see Wetzel & Mondolfi [1979] for description on how to take this measure); condylar process of mandible lower and sessile; and minute teeth.</p> <p> <b>Comparative description.</b> Externally, <i>Cryptophractus pilosus</i> has the whole carapace covered by a thick coating of rigid, long, yellow to light-brown hairs that completely conceal the carapace, but for the antero-lateral margin of the scapular buckler (Fig. 4). The same type of hair is present in the cheeks and proximal portion of the limbs; shorter and less abundant hair covers the ventral surface of the body, where brownish transversal lines in the skin are in continuation to the movable bands. These areas also show some flat isolated osteoderms within the skin. <i>Cryptophractus pilosus</i> has five digits in the feet and four in the hands; a vestigial fifth digit is externally visible only in <i>D. kappleri</i> (but see Costa & Vizcaíno 2010). The ears are large and conical, covered with pebbly skin, whereas the eyes are a small slit.</p> <p> The external measurements (Table 1) agree with previous observations on the species (Fitzinger 1871; Flower 1886; Frechkop & Yepes 1949; Wetzel & Mondolfi 1979; Wetzel 1985). Only three adult specimens analyzed have weight data (MUSM 7501=2.30 kg; MUSM 7504=1.40 kg; MUSM 7505=1.85 kg), being on the upper range or slightly heavier than <i>D. septemcinctus</i> (1.45–1.80 kg), <i>D. hybridus</i> (2.04 kg) and <i>D. sabanicola</i> (1.00–2.00 kg) (Hamlett 1939; Wetzel & Mondolfi 1979). The average total length also indicates that <i>C. pilosus</i> is larger than these species and <i>D. yepesi</i>, whereas is smaller than <i>D. novemcinctus</i> and <i>D. kappleri</i> (Wetzel & Mondolfi 1979). As observed in <i>D. novemcinctus</i> (McBee & Baker 1982), apparently the males (MUSM 2056, 7501) of <i>C. pilosus</i> are slightly larger than the females (MUSM 7504, 7505), as shown in Tables 1–3.</p> <p> <b>TABLE 1.</b> External lengths of <i>Cryptophractus pilosus</i> (mm), taken from dried specimens. Averages calculated excluding the juvenile specimens.</p> <p> With respect to the carapace, the cephalic shield is narrow and elongate, roughly rhomboid, and the osteoderms does not form rosettes; the posterior end is acute, more distantly separated from the base of the ears, and has a Vshaped occipital sulcus; anteriorly, the osteoderms become gradually irregular in shape, loosely articulated to each other, and arranged in lines parallel to the sagittal plan. The morphology of the cephalic shield differs from that of <i>Dasypus</i> spp., as was illustrated by Frechkop & Yepes (1949) and Kraft (1995). The pelvic buckler is variably longer than the scapular buckler (Table 2). The latter has a round anterior border (angular only in <i>D. kappleri</i>). The number of completely movable bands ranges from 9 to 11 (n=8). Besides of being more numerous than in <i>Dasypus</i> spp. (Hamlett 1939; Wetzel & Mondolfi 1979; Vizcaíno 1995), each band is anteroposteriorly shorter. Also our observation on a dry carapace (MUSM-ING 633) suggests limited mobility among the four anterior bands, which seem to be fused with each other. The cylindrical tail corresponds to 65–76% of the head-body length, similarly to <i>D. kappleri</i> and <i>D. novemcinctus</i> and much longer than the other species of <i>Dasypus</i>; its posterior third gradually tapers, whereas the proximal two-thirds is partitioned in 7–11 rings (n=8), each composed of two rows of osteoderms with scarce hairs on the posterior margin of each ring.</p> <p>The morphology and ornamentation of the osteoderms are described here for the first time confirming that it is unique in relation to all extant armadillos (Fig. 4 and 5). They lack principal or radial sulci. The foramina of the buckler osteoderms are arranged in a central circle bounding a nearly circular central figure, which have small neurovascular foramina inside it. A second row of similar foramina forms a posterior semicircle. The total number of foramina per osteoderm (including some confluent ones) is about 30 in the scapular and 35 in the pelvic osteoderms. The pelvic elements have bigger and more lacerated foramina. Scapular semimovable osteoderms have a semicircular arch of foramina in the mid part and at least two rows of foramina in the posterior border, together forming a nearly circular figure. Pelvic semimovable and movable osteoderms have one or two large foramina anteriorly. The foramina are distributed within an inverted “V” pattern in the formers, and their size decrease posteriorly. The foramina in the movable osteoderms are arranged in two posteriorly divergent lines, which are connected distally by a semicircular arc, forming a triangular principal figure; a circular figure is limited anteriorly by an additional, but inverted, semicircular arc of foramina at mid-length; the posterior margin is copious of foramina, arranged in two or three rows; the size of the foramina also decrease posteriorly. The observations on two specimens (MUSM 24214 and MUSM-ING 633) indicate that, despite the great size of the foramina in the osteoderms, a single hair comes out of each foramen.</p> <p> The horn scales are thicker than in <i>Dasypus</i> spp., with irregular borders and numerous perforations for hair emersion. Several depositional layers are visible from inside to outside. Each buckler osteoderm is covered by a central scale and about six peripheral scales that also cover part of adjoining osteoderms. In movable osteoderms the principal figure is covered by a triangular and a circular scale, and inverted triangles cover the peripheral figures of two adjoining elements (Fig. 5).</p> <p> The skull of <i>Cryptophractus pilosus</i> is unique in having the longest and narrowest rostrum of all extant armadillos. The lateral margins of the rostrum are sub-parallel in dorsal view but its anterior tip is slightly broader (Fig. 6 A). A delicate sagittal crest is present in most of the adult specimens (e.g., MUSM 7504), a rare feature in <i>Dasypus</i> spp. Anterior to the interorbital constriction the frontals are delicately vaulted by the development of frontal sinuses. The anterior processes of the frontals are more elongated than in <i>Dasypus</i> to contact the longer nasal bones.</p> <p> In the ventral aspect of the skull (Fig. 6 B), the maxillae, and occasionally the premaxillae, are concave along the sagittal line. The palate corresponds to 68–74% (70% on average, n=7) of the maximum skull length, including juveniles, confirming the observations of Wetzel & Mondolfi (1979). In relation to <i>D. novemcinctus</i>, the increase of the palatal length in <i>C. pilosus</i> is achieved by the extension of the maxillae and premaxillae, whereas the palatines remain proportionally equal. The palatines are flat, with a heart-shaped anterior border and rounded lateral margins. The posterior border of the palate, comprising palatines and pterygoids, is indented medially with a contour varying from a long and narrow “V” to bell-shaped. This condition differs from <i>D. kappleri</i>, which has a straight and roughly square internal nasal aperture. The free border of the pterygoids has a sharp ventral projection, forming a triangular outline in lateral view. The glenoid articulation is oval and flat, with a ventrally projecting postglenoid process. The foramen ovale and the transverse canal foramen are separated in all available specimens, whereas these are confluent in some specimens of <i>Dasypus</i> spp.</p> <p> In lateral view (Fig. 6 C), the dorsal contour of the rostrum is approximately straight, as in <i>D. hybridus</i> and <i>D. septemcinctus</i>, whereas it is markedly sigmoid in the other <i>Dasypus</i> species. The zygomatic arch is dorso-ventrally thinner than in <i>D. novemcinctus</i> and the crest for insertion of masseter muscle is weaker. The lacrimal is proportionally smaller, as in <i>D. hybridus</i>, and possesses one or exceptionally two lacrimal foramina. The morphology of the contact between the petrosal and the squamosal varies from a shallow occipital groove in the youngest specimen (MUSM 7503) to an occipital canal with different degrees of closure in the adults, as described for <i>D. novemcinctus</i> (Wible 2010). Five specimens (MUSM 7500, 7501, 7503, 7504, and 7505) preserve the ectotympanic and the ossicles of the middle ear. Adults present an ossified entotympanic that partially covers the ventral part of the petrosal, running medially to the ectotympanic from its the posterior part until the alisphenoidpterygoid suture (Fig. 7); only in MUSM 7503, a juvenile, the ossification of the entotympanic has a middle gap between two ossifications. In <i>D. novemcinctus</i>, the only extant <i>Dasypus</i> with detailed studies on the auditory region, the entotympanic is poorly developed, composed by small isolated ossifications (Patterson <i>et al.</i> 1989; Wible 2010). The same pattern was observed in <i>D. septemcinctus</i> (MNRJ 10062; Fig. 7).</p> <p> The slender mandible (Fig. 6 D) shows a straighter horizontal ramus, much slender than in extant related species. The angular process is blunt and the condylar process is lower and sessile (whereas it has a neck with variable development in <i>Dasypus</i>).</p> <p> Table 3 shows some cranial measurements of <i>Cryptophractus pilosus</i>. They are consistent with previous observations on the species (Wetzel & Mondolfi 1979; Wetzel 1985). The skull length and the zygomatic width are only smaller than in <i>D. kappleri</i> and than the largest specimens of <i>D. novemcinctus</i>. With respect to the rostral ratio (=length of the rostrum/maximum skull length), excluding juvenile specimens, it varies between 0.62 and 0.69, with an average of 0.66. According to data presented by Wetzel & Mondolfi (1979), this ratio is slightly higher than that of <i>D. kappleri</i> (0.64 on average) and sensibly exceeds those of <i>Dasypus</i> (<i>Dasypus</i>) group, which are mostly below 0.62 in <i>D. novemcinctus</i> and about 0.56 in <i>D. septemcinctus</i>, <i>D. hybridus</i>, and <i>D. sabanicola</i>; the rostral ratio of <i>D. yepesi</i> (0.55, calculated for MLP 30-III-90 -8) agrees with the other small species.</p> <p> Like in <i>Dasypus</i> (Ciancio <i>et al.</i> 2012), the peg-like molariforms of <i>Cryptophractus pilosus</i> have an anteriorposterior beveled occlusal relief (Figs. 6 C and 6D). However, the teeth are substantially smaller (with approximately 1 mm long and 0.7 mm wide) and subcylindrical (instead of prismatic with subrectangular crosssections). There are 7 to 8 upper and 7 to 9 lower molariforms, a tooth count higher than the 5/6 observed by Wetzel (1985). The dental series occupy only a short portion of the maxilla and mandible, leaving an extensive edentulous anterior section, longer than the dental series itself. Closed or aborted alveoli are highly frequent in the material analyzed. Previous studies in <i>Dasypus</i> spp. showed that a thin enamel layer is present in the apical portion of deciduous and permanent teeth, but is lost soon after the eruption; also the two real cusps (labial and lingual), are worn leaving secondary labial and lingual borders (Martin 1916; Ciancio <i>et al.</i> 2010). Further studies are required to confirm the presence of dental enamel in <i>C. pilosus</i>.</p> <p> A single specimen (MUSM 24214) has appendicular and axial elements preserved, mostly with unfused epiphyses, suggesting an immature condition of the skeleton. It includes three thoracic and five lumbar vertebrae, sinsacrum, right femur, tibia-fibula, astragalus, calcaneus, navicular, plantar sesamoid, metatarsals, and phalanges. Anatomical comparisons were made among these elements and those of <i>Dasypus</i> species (including a young juvenile specimen of <i>D. septemcinctus</i>), except for <i>D. sabanicola</i>. Figure 8 compares equivalent postcranial elements of <i>C. pilosus</i> and <i>D. novemcinctus</i>. In <i>C. pilosus</i>, the lumbar vertebrae have shorter neural spines and metapophyses and, in lateral view, the angle formed between these apophyses is wider. The morphology of the xenarthrous articulations is concordant with the description of Gaudin (1999). The synsacrum is proportionally longer, composed of seven vertebrae (varying from seven to nine in <i>Dasypus</i> spp.), although the irregular posterior margin of the transverse processes of the last one suggests the presence of an eighth posteriorly incorporated element. The iliac crest is more recurved and more laterally projected, as wide as the ischia. The femur is slenderer; oddly a hair pierces the posterior surface of the shaft. The tibia and fibula are not yet fused at their distal ends, as observed in adults of <i>Dasypus</i>. Compared to <i>D. novemcinctus</i> and <i>D. hybridus</i>, the astragalus of <i>C. pilosus</i> has a longitudinal separation in the tibial facet, the neck lacks ridges on the dorsal surface, and the sustentacular and navicular facets are larger. Both calcaneal heel and head are proportionally broader, the ectal facet extends further over the calcaneal heel, and laterally the peroneal process is incipient. Jasinski & Wallace (2014) hypothesized that a greater development of this process (as present in <i>D. novemcinctus</i>) may be related to semifossorial habits. No differences were observed in the remaining elements.</p> <p> <b>Habitat and biology</b>. The predicted distribution of <i>C. pilosus</i> (NatureServe 2014) includes a narrow montane strip in Peru from Amazonas to Junín Departments. Consequently, due to deforestation of montane habitats the conservation status of <i>C. pilosus</i> is vulnerable (Pacheco 2002; Superina & Abba 2010). Its ecology and behavior are completely unknown (Wetzel <i>et al.</i> 2007). In this regard we report the occurrence of multiple embryos in the species based on the observation of a female with four embryos (MUSM 7504). Also, a tick identified as <i>Ixodes</i> sp. was found attached to the skin of other specimen (MUSM 7499).</p> <p> With respect to diet, it is predominantly based on insects in <i>D. sabanicola</i> and in <i>D. novemcinctus</i> (Mondolfi 1967, McBee & Baker 1982, Smith & Redford 1990). Numerous morphological adaptations for myrmecophagy (=termitophagy) were recognized in <i>D. novemcinctus</i> (Moeller 1968; Wetzel & Mondolfi 1979; Smith & Redford 1990; Charles <i>et al.</i> 2013). In <i>C. pilosus</i>, some of these characters are even more accentuated, such as a longer and narrower rostrum, the shorter dental series composed of minute teeth, frequent closed/aborted alveoli in adults, and lower and sessile mandibular condyle. These features suggest a predominantly ant and termite-eating diet, although no direct observations of feeding activity has been recorded. Also, the skull, mandible, and teeth of the mid-sized fossil armadillo <i>Stegotherium</i> (early–middle Miocene of Patagonia) shows similarities to <i>C. pilosus</i>. Although phylogenetic studies support a close relationship between this genus and Dasypodini (Engelmann 1985; Gaudin & Wible 2006; and the present cladistic analysis), the resemblances between <i>Stegotherium</i> and <i>C. pilosus</i> might reflect a convergence related to their feeding habits, as a myrmecophagous diet was also inferred for the former (Vizcaíno 1994).</p>Published as part of <i>Castro, Mariela C., Ciancio, Martín R., Pacheco, Víctor, Salas-Gismondi, Rodolfo M., Bostelmann, J. Enrique & Carlini, Alfredo A., 2015, Reassessment of the hairy long-nosed armadillo " Dasypus " pilosus (Xenarthra, Dasypodidae) and revalidation of the genus Cryptophractus Fitzinger, 1856 in Zootaxa 3947 (1)</i>, DOI: 10.11646/zootaxa.3947.1.2, <a href="http://zenodo.org/record/236643">http://zenodo.org/record/236643</a&gt

Cryptophractus Fitzinger 1856

Genus <i>Cryptophractus</i> Fitzinger, 1856 [nomen revalidatum] <p> <i>Cryptophractus</i> Fitzinger, 1856: 123.</p> <p> <i>Praopus</i> Burmeister, 1854 [part]: Burmeister 1862:147; new species.</p> <p> [<i>Tatusia</i> (<i>Cryptophractus</i>)] Cuvier, 1822 [part]: Trouessart 1898:1140; name combination and new rank. [<i>Tatus</i> (<i>Cryptophractus</i>)] Frisch, 1775: Trouessart, 1905:814; name combination.</p> <p> <i>Tatu</i> Blumenbach, 1779 [part]: Thomas, 1927:605; name combination.</p> <p> <i>Dasypus</i> Linnaeus, 1758 [part]: Yepes, 1928:468; name combination.</p> <p> <i>Dasypus</i> (<i>Cryptophractus</i>) Linnaeus, 1758: Talmage & Buchanan, 1954:84; new rank.</p> <p> <b>Type species.</b> <i>Cryptophractus pilosus</i> Fitzinger, 1856 <b>Diagnosis.</b> As the species by monotypy.</p>Published as part of <i>Castro, Mariela C., Ciancio, Martín R., Pacheco, Víctor, Salas-Gismondi, Rodolfo M., Bostelmann, J. Enrique & Carlini, Alfredo A., 2015, Reassessment of the hairy long-nosed armadillo " Dasypus " pilosus (Xenarthra, Dasypodidae) and revalidation of the genus Cryptophractus Fitzinger, 1856 in Zootaxa 3947 (1)</i>, DOI: 10.11646/zootaxa.3947.1.2, <a href="http://zenodo.org/record/236643">http://zenodo.org/record/236643</a&gt

Data from: Late Oligocene caviomorph rodents from Contamana, Peruvian Amazonia

The Deseadan South American Land Mammal Age (late Early Oligocene – Late Oligocene) attests to a time of great diversification in the caviomorph rodent fossil record. Nevertheless, Deseadan rodent-bearing localities in Neotropical lowlands are few and poorly known. Here we describe the rodent assemblages from two Late Oligocene localities, near Contamana, Loreto, Peru. Seven taxa are new to science: Palaeosteiromys amazonensis gen. et sp. nov., Plesiosteiromys newelli gen. et sp. nov., Loretomys minutus gen. et sp. nov., Scleromys praecursor sp. nov, Ucayalimys crassidens gen. et sp. nov., Chambiramys sylvaticus gen. et sp. nov. and Chambiramys shipiborum gen. et sp. nov. These rodent faunas show that caviomorphs were relatively diverse in Peruvian Amazonia during the Late Oligocene, with the co-occurrence of at least three extant superfamilies: Erethizontoidea, Octodontoidea and Chinchilloidea. Additionally, they mark the earliest known occurrences of Scleromys, of a small erethizontid closely related to Microsteiromys and of an adelphomyine closely reminiscent of Ricardomys (all taxa previously restricted to Miocene localities thus far). They also document a form potentially related to Eosallamys (previously known from around the Eocene–Oligocene transition at Santa Rosa in Peruvian Amazonia). Finally, the geographical range of Adelphomyinae and of Deseadomys is widely expanded to the lower latitudes of South America for the Deseadan interval. The latter elements, in addition to the record of a very primitive species of Scleromys, suggest the absence of palaeogeographical and palaeoenvironmental barriers within the southern cone of South America before the Oligocene–Miocene transition

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

Miocene deposits of South America have yielded several species-rich assemblages of caviomorph rodents. They are mostly situated at high and mid- latitudes of the continent, except for the exceptional Honda Group of La Venta, Colombia, the faunal composition of which allowed to describe the late middle Miocene Laventan South American Land Mammal Age (SALMA). In this paper, we describe a new caviomorph assemblage from TAR-31 locality, recently discovered near Tarapoto in Peruvian Amazonia (San Martín Department). Based on mammalian biostratigraphy, this single-phased locality is unambiguously considered to fall within the Laventan SALMA. TAR-31 yielded rodent species found in La Venta, such as the octodontoid Ricardomys longidens Walton, 1990 (nom. nud.), the chinchilloids Microscleromys paradoxalis Walton, 1990 (nom. nud.) and M. cribriphilus Walton, 1990 (nom. nud.), or closely-related taxa. Given these strong taxonomic affinities, we further seize the opportunity to review the rodent dental material from La Venta described in the Ph.D. volume of Walton in 1990 but referred to as nomina nuda. Here we validate the recognition of these former taxa and provide their formal description. TAR-31 documents nine distinct rodent species documenting the four extant superfamilies of Caviomorpha, including a new erethizontoid: Nuyuyomys chinqaska gen. et sp. nov. These fossils document the most diverse caviomorph fauna for the middle Miocene interval of Peruvian Amazonia to date. This rodent discovery from Peru extends the geographical ranges of Ricardomys longidens, Microscleromys paradoxalis, and M. cribriphilus, 1,100 km to the south. Only one postcranial element of rodent was unearthed in TAR-31 (astragalus). This tiny tarsal bone most likely documents one of the two species of Microscleromys and its morphology indicates terrestrial generalist adaptations for this minute chinchilloid

Genre et espece indet. 2 Bennett 1833

<p>Genre et espèce indet. 2 (Fig. 4R, S; Tableau 1)</p> <p>MATÉRIEL. — MUSM-3381, m2 droite (Fig. 4R); MUSM-3380, dP4 gauche (Fig. 4S).</p> <p>LOCALITÉ. — TAR-45, Juanjui, Département de San Martín, Pérou.</p> <p>DESCRIPTION</p> <p>MUSM-3381 et MUSM-3380 sont brachyodontes, tétralophodontes et téniodontes. Elles présentent un contour quadrangulaire. Bien que davantage usée sur la moitié labiale, MUSM-3381 présente quatre cuspides bien marquées (Fig. 4R). Le métaconide est crestiforme et forme l’angle antéro-lingual de la dent. Il présente un bras postérieur très large et long, à l’extrémité duquel se connecte un mésostylide à peine distinct. Le métalophulide I, rectiligne, présente une encoche labiale. Le protoconide, bulbeux, possède un bras postérieur robuste et oblique connecté à une deuxième cristide divisée en deux parties distinctes: une partie labiale peu épaisse d’orientation mésiodistale, et une partie linguale sinueuse et qui s’étend jusqu’à la base du mésostylide, laissant une encoche qui permet la connexion de l’antéroflexide et du mésoflexide. De l’entoconide s’étend un hypolophide transverse et séparé du bras postérieur du protoconide par un fort ectolophide rectiligne, orienté mésiodistalement. L’entoconide présente un fort bras postérieur qui forme un bourrelet, lequel est fusionné au postérolophide. Ce dernier est épais et courbé entre l’entoconide et l’hypoconide, cette cuspide étant crestiforme et oblique. Le bras antérieur issu de l’hypoconide est absent mais l’épaississement basal des cristides peut entraîner une connexion de l’hypoconide avec l’hypolophide aux stades avancés d’usures de la dent.</p> <p>La dP4 (MUSM-3380; Fig. 4S) présente une forme trapézoïdale due au rapprochement de l’hypocône avec le protocône, plus distal que le paracône. L’antérolophe et le bras antérieur de l’hypocône sont obliques. Ce dernier se connecte à la troisième crête et au protolophe labial, tous deux étant transverses. La connexion entre le protolophe labial et le bras antérieur de l’hypocône est incomplète et forme une encoche. La partie distale de MUSM-3380 est cassée à hauteur du métacône et de l’hypocône.</p> <p>COMPARAISONS</p> <p> Ces deux spécimens, dont la morphologie indique qu’ils appartiennent à des caviomorphes basaux (<i>sensu</i> Boivin <i>et al.</i> 2019a), diffèrent de ceux attribués aux genres <i>Cachiyacuy, Canaanimys</i> et <i>Eoespina</i> par la téniodontie des molaires inférieures; de <i>Cachiyacuy</i> et <i>Canaanimys</i> par la présence d’un protoconide peu crestiforme (à stade d’usure équivalent); d’ <i>Eoespina</i> par la présence d’une deuxième cristide transverse incomplète. Il nous paraît à ce jour impossible de les attribuer à un genre ou à une espèce déjà formellement nommés.</p>Published as part of <i>Assemat, Alexandre, Boivin, Myriam, Marivaux, Laurent, Pujos, François, Benites-Palomino, Aldo, Salas-Gismondi, Rodolfo, Tejada-Lara, Julia V., Varas-Malca, Rafael M. & Negri, Francisco Ricardo, 2019, Restes inédits de rongeurs caviomorphes du Paléogène de la région de Juanjui (Amazonie péruvienne): systématique, implications macro-évolutives et biostratigraphiques, pp. 699-730 in Geodiversitas 41 (20)</i> on pages 714-715, DOI: 10.5252/geodiversitas2019v41a20, <a href="http://zenodo.org/record/3695780">http://zenodo.org/record/3695780</a&gt

Eoespina sp. Assemat 2019

<i>Eoespina</i> sp. <p>(Fig. 3 M-O; Tableau 1)</p> <p>MATÉRIEL. — MUSM-3383, M1-2 droite sub-complète (Fig. 3M); MUSM-3524, M2 gauche fragmentaire (Fig. 3N); MUSM-3384, M1-2 droite cassée lingualement (Fig. 3O).</p> <p>LOCALITÉ. — TAR-47, Juanjui, Département de San Martín, Pérou.</p> <p>DESCRIPTION</p> <p>MUSM-3383 (Fig. 3M) et MUSM-3524 (Fig.3N) sont tétralophodontes, brachyodontes, non téniodontes et possèdent un contour arrondi, ainsi que des crêtes étroites et hautes délimitant des fosses et flexi profonds. Les cuspides sont bien marquées et reliées par des crêtes rectilignes, à l’exception du bras antérieur de l’hypocône qui est oblique. Le protocône est bulbeux et présente une forte excroissance postérieure. La partie linguale du protolophe est moins développée que la partie labiale, mais sépare l’hypoflexus de la parafossette, ou du paraflexus à des stades d’usure moindres. Le paracône est relié à la mure par le protolophe labial, lequel est épais. Une troisième crête s’étend labiolingualement entre le mésostyle et la jonction mure/ bras antérieur de l’hypocône. Le métacône et le métalophe ne sont pas distincts. Cependant, la région postérolabiale du postérolophe est très épaisse, et témoigne probablement d’un complexe métalophe-métacône-postérolophe.</p> <p>MUSM-3384 (Fig. 3O) présente un patron occlusal similaire à celui observé chez MUSM-3383 (Fig. 3M), mais l’ouverture labiale du paraflexus y est visible (usure moins avancée). Concernant la troisième crête transverse, un long mésolophule se connecte labialement à un très court mésolophe partant du mésostyle. Une tubérosité est située sur le postérolophe, lingualement au métacône, et pourrait indiquer la présence des vestiges d’un métalophe se connectant au postérolophe.</p> <p>COMPARAISONS</p> <p> MUSM-3383, MUSM-3524 et MUSM-3384 diffèrent des molaires supérieures de <i>Cachiyacuy</i> et de <i>Canaanimys</i>, par leur tétralophodontie et l’aspect arrondi de leur contour occlusal, caractères qui les rapprochent plutôt d’ <i>Eoespina</i>; elles diffèrent néanmoins des molaires supérieures d’ <i>Eoespina</i> par l’absence de fermeture labiale de la postérofossette et la présence d’un renflement plus marqué sur le postérolophe; elles diffèrent plus encore de celles de <i>Mayomys confluens</i>, par l’absence de fusion du mésostyle avec le métacône, et l’absence d’une fermeture labiale du postéroflexus. Le matériel n’est pas suffisant pour soutenir une identification spécifique, mais il peut être assigné avec confiance au genre <i>Eoespina</i> (<i>sensu</i> Boivin <i>et al.</i> 2017a) et laissé en nomenclature ouverte.</p>Published as part of <i>Assemat, Alexandre, Boivin, Myriam, Marivaux, Laurent, Pujos, François, Benites-Palomino, Aldo, Salas-Gismondi, Rodolfo, Tejada-Lara, Julia V., Varas-Malca, Rafael M. & Negri, Francisco Ricardo, 2019, Restes inédits de rongeurs caviomorphes du Paléogène de la région de Juanjui (Amazonie péruvienne): systématique, implications macro-évolutives et biostratigraphiques, pp. 699-730 in Geodiversitas 41 (20)</i> on page 712, DOI: 10.5252/geodiversitas2019v41a20, <a href="http://zenodo.org/record/3695780">http://zenodo.org/record/3695780</a&gt

Canaanimys aff. maquiensis Antoine, Marivaux, Croft, Billet, GanerOd, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi 2012

<i>Canaanimys</i> aff. <i>maquiensis</i> <p>(Fig. 4O, P; Tableau 1)</p> <p>MATÉRIEL. — MUSM-3371, M3 gauche complète (Fig. 4O); MUSM-3379, fragment de M3 gauche (Fig. 4P).</p> <p>LOCALITÉS. — TAR-55 & TAR-55bis, Balsayacu, Département de San Martín, Pérou.</p> <p>DESCRIPTION</p> <p>MUSM-3371 (Fig. 4O) est brachyodonte, tétralophodonte et non téniodonte. Elle présente un contour arrondi ainsi que des lophes grêles, peu épais.Toutes les crêtes sont transverses, à l’exception du bras antérieur de l’hypocône, dans la continuité de ce dernier. Le métacône est petit et sensiblement égal en taille au mésostyle. La molaire présente un protocône et un hypocône crestiformes. Le postérolophe relie l’hypocône à la base du métacône. Il n’y a pas de métalophe dans la partie distolabiale de la dent, mais on peut noter la présence d’une postérofossette très ouverte dans laquelle s’individualisent des crestules d’émail, lesquelles peuvent être interprétées comme des néoformations ou des vestiges du métalophe. Le bras antérieur de l’hypocône, très développé, s’étend jusqu’à rejoindre une troisième crête transverse qui semble être un mésolophule, s’arrêtant à la base du mésostyle. De plus, la dent ne possède qu’une mure très peu marquée, sous la forme d’un éperon situé à l’extrémité mésiale du bras antérieur de l’hypocône. Cet éperon est à peine connecté au protolophe. Ce dernier est complet et épais, empêchant la confluence de l’hypoflexus avec le paraflexus. L’antérolophe est courbé et peu élevé; il s’étend du protocône à la base du paracône. Le paraflexus et le mésoflexus mésial sont profonds et étroits montrant la proximité des lophes sur la partie antérieure de la dent.</p> <p>MUSM-3379 (Fig. 4P) est cassée antérieurement mais présente un patron occlusal assez similaire à celui de MUSM- 3371. À l’inverse du paracône bien développé, le métacône est réduit à une petite protubérance à l’extrémité labiale du postérolophe. Le mésostyle est bien développé. Le protolophe labial est robuste et non rectiligne. Le protolophe lingual est matérialisé par deux éperons d’émail (i.e., pseudo-téniodontie): le premier haut, épais et directement issu du protolophe labial et le second très fin et très bas reliant le premier éperon au protocône. Ce dernier se connecte à une mure incomplète et très basse. Du mésostyle part une troisième crête étroite qui semble être un mésolophe, se connectant au bras antérieur de l’hypocône. La présence d’une encoche entre le métacône et le mésostyle ouvre le flexus postérieur labialement.</p> <p>COMPARAISONS</p> <p> Ce matériel est rapproché du genre <i>Canaanimys</i> (seulement connu par l’espèce type <i>C. maquiensis</i> à CTA-27; Antoine <i>et al.</i> 2012; Boivin <i>et al.</i> 2017a), car il présente des crêtes étroites, transverses, des crestules pouvant être assimilées à un métalophe vestigial dirigé antérieurement ainsi qu’un grand flexus postérieur. Il diffère de ce dernier par la présence d’une téniodontie moins marquée ainsi que d’un métalophe incomplet. Il diffère également de <i>Cachiyacuy</i> par la taille de son flexus (ou fossette) postérieur et la présence d’une pseudo-téniodontie à téniodontie de la M3; d’ <i>Eobranisamys</i> par l’absence de métalophe sur la M3 et l’aspect plus transverse de ses lophes. Compte tenu de leur patron morphologique, nous assignons ces spécimens à <i>Canaanimys</i> aff. <i>maquiensis</i>.</p>Published as part of <i>Assemat, Alexandre, Boivin, Myriam, Marivaux, Laurent, Pujos, François, Benites-Palomino, Aldo, Salas-Gismondi, Rodolfo, Tejada-Lara, Julia V., Varas-Malca, Rafael M. & Negri, Francisco Ricardo, 2019, Restes inédits de rongeurs caviomorphes du Paléogène de la région de Juanjui (Amazonie péruvienne): systématique, implications macro-évolutives et biostratigraphiques, pp. 699-730 in Geodiversitas 41 (20)</i> on page 712, DOI: 10.5252/geodiversitas2019v41a20, <a href="http://zenodo.org/record/3695780">http://zenodo.org/record/3695780</a&gt

Cachiyacuy cf. kummeli Antoine, Marivaux, Croft, Billet, GanerOd, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi 2012

<i>Cachiyacuy</i> cf. <i>kummeli</i> <p>(Fig. 3 A-G; Tableau 1)</p> <p>MATÉRIEL. — MUSM-3373, m1 gauche (Fig. 3E); MUSM-3374, m2 droite (Fig. 3G); MUSM-3375, m2 droite (Fig. 3F); MUSM- 3372, P4 gauche (Fig. 3A); MUSM-3378, M1 gauche (Fig. 3D); MUSM-3376, M2 gauche (Fig. 3B); MUSM-3377, M2 droite (Fig. 3C).</p> <p>LOCALITÉ. — TAR-55bis, Balsayacu, Département de San Martín, Pérou.</p> <p>DESCRIPTION</p> <p>La m1 (MUSM-3373; Fig. 3E) présente un contour subrectangulaire, caractérisé par un métaconide très anguleux et dominant. Cette molaire est tétralophodonte et non téni- odonte. Le protoconide et l’entoconide sont bien marqués tandis que l’hypoconide est d’apparence crestiforme, mais se distinguant encore du postérolophide. L’obliquité des cristides est faible et l’émail peu épais. Les vallées sont relativement profondes par rapport à la hauteur des cristides. Le métalophulide I est rectiligne mais discontinu. Il est composé du bras antérieur du protoconide et de celui du métaconide, lesquels se connectent centralement sur l’axe labiolingual. Un faible bourrelet d’émail, situé distalement sur le bras postérieur du métaconide, indique la présence d’un mésostylide. De ce dernier s’étend la deuxième cristide, sinueuse et composée d’un néomésolophide court qui rejoint le long bras postérieur du protoconide connecté à l’ectolophide. Le bras antérieur de l’hypoconide est bien marqué et orienté obliquement de l’hypoconide vers l’hypolophide. Le postérolophide rejoint l’entoconide à sa base, laissant une encoche ouvrant le métaflexide lingualement.</p> <p>Les m2 (MUSM-3374 et 3375; Fig. 3F, G) présentent une architecture occlusale similaire à celle observée sur les m1, mais en différent par leur forme plus quadrangulaire et transverse.</p> <p>La M1 MUSM-3378 (Fig. 3D) est brachyodonte, tétralophodonte, non téniodonte et présente un émail plus épais lingualement que labialement. Les cuspides sont bien définies et les lophes sont rectilignes et transverses. Seul le bras antérieur de l’hypocône est orienté obliquement et se connecte à la mure. Le postérolophe est épais et pourrait correspondre à un complexe métacône-métalophe-postérolophe (voir Boivin & Marivaux 2018). Le mésostyle est marqué, et de ce dernier part un long mésolophe connecté au bras antérieur de l’hypocône via un mésolophule peu marqué et très court. Une crête accessoire connecte le mésolophe au postérolophe/complexe (métacône-métalophe-postérolophe), délimitant ainsi deux fossettes postérieures: la première est triangulaire, peu étendue et située labialement à l’hypocône, et la seconde est sub-ovale, plus étendue et longeant le mésolophe. Le protolophe labial est rectiligne, légèrement oblique, et relie le paracône de petite taille au protolophe lingual. Ce dernier ferme lingualement l’antérofossette. L’antérolophe, reliant le très large protocône au paracône, ferme l’antérofossette labialement.</p> <p>Les M2 (MUSM-3376 et MUSM-3377; Fig. 3B, C) ont une morphologie occlusale similaire à celle de la M1, mais présentent un contour plus transverse et arrondi du fait de la courbure marquée de leur antérolophe et de leur postérolophe. Les cuspides sont bulbeuses à l’exception du protocône qui est crestiforme. Le mésostyle est bien marqué, occupant une position légèrement plus labiale que les deux autres cuspides labiales.</p> <p>COMPARAISONS</p> <p> Ce taxon diffère de <i>Canaanimys maquiensis</i> Antoine, Marivaux, Croft, Billet, GanerØd, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, par la tétralophodontie de ses M1-2 et la présence d’une deuxième cristide complète et robuste sur les molaires inférieures; de <i>Mayomys confluens</i> Boivin, Marivaux, Pujos, Salas-Gismondi, Tejada-Lara, Varas-Malca & Antoine, 2018 par la présence d’un métaconide très anguleux sur les molaires inférieures; et de <i>Cachiyacuy kummeli</i> Antoine, Marivaux, Croft, Billet, GanerØd, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, par sa plus grande taille et la présence d’une connex- ion du postérolophide plus basse sur l’entoconide, lequel est moins élevé que chez ce dernier. Il est toutefois à rapprocher de cette dernière espèce, avec laquelle il présente de plus fortes ressemblances.</p>Published as part of <i>Assemat, Alexandre, Boivin, Myriam, Marivaux, Laurent, Pujos, François, Benites-Palomino, Aldo, Salas-Gismondi, Rodolfo, Tejada-Lara, Julia V., Varas-Malca, Rafael M. & Negri, Francisco Ricardo, 2019, Restes inédits de rongeurs caviomorphes du Paléogène de la région de Juanjui (Amazonie péruvienne): systématique, implications macro-évolutives et biostratigraphiques, pp. 699-730 in Geodiversitas 41 (20)</i> on page 706, DOI: 10.5252/geodiversitas2019v41a20, <a href="http://zenodo.org/record/3695780">http://zenodo.org/record/3695780</a&gt