Mariela C. Castro

Evolutionary Implications of Dental Eruption in Dasypus (Xenarthra)

Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of endemic African mammals (Afrotheria), with anecdotal reports indicating that it is also present in dasypodids (armadillos). In order to clarify this question, and address the possiblity that late eruption is shared by afrotherians and dasypodids, we quantified the eruption of permanent teeth in Dasypus, focusing on growth series of D. hybridus and D. novemcinctus. This genus is the only known xenarthran that retains two functional generations of teeth. Its adult dentition typically consists of eight upper and eight lower ever-growing (or euhypsodont) molariforms, with no premaxillary teeth. All but the posterior-most tooth are replaced, consistent with the identification of a single molar locus in each series. Comparison of dental replacement and skull metrics reveals that most specimens reach adult size with none or few erupted permanent teeth. This pattern of growth occurring prior to the full eruption of the dentition is similar to that observed in most afrotherians. The condition observed in Dasypus and many afrotherians differs from that of most other mammals, in which the permanent dentition erupts during (not after) growth, and is complete at or near the attainment of sexual maturity and adult body size. The suture closure sequence of basicranial and postcranial epiphyses does not correlate well with dental eruption. The basal phylogenetic position of the taxon within dasypodids suggests that diphyodonty and late dental replacement represent the condition of early xenarthrans. Additionally, the inferred reduction in the number of molars to a single locus and the multiplication of premolars represent rare features for any living mammal, but may represent apomorphic characters for Dasypus.

Reassessment of the hairy long-nosed armadillo "Dasypus" pilosus (Xenarthra, Dasypodidae) and revalidation of the genus Cryptophractus Fitzinger, 1856.

The hairy long-nosed armadillo, currently referred as Dasypus (Cryptophractus) pilosus, is an enigmatic species endemic to montane cloud forests and subparamo of Peruvian Andes. Its strikingly different external features, which include the carapace concealed by abundant hair, the presence of more movable bands, and a slender skull, have raised questions regarding its taxonomic status as subgenus or as genus. This paper assesses this issue based on a cladistic study and provides a detailed comparative description of the species, including the first account on the distinctive ornamentation of its osteoderms. Based on several unique characters in the carapace, skull, mandible, and teeth, as well as on the external phylogenetic position relative to other Dasypus, we favor the assignment of the hairy long-nosed armadillo to other genus. As result, we revalidate the original generic epithet, so that the valid name of the species is Cryptophractus pilosus Fitzinger, 1856.

Redescription of Dasypus punctatus Lund, 1840 and Considerations on the Genus Propraopus Ameghino, 1881 (Xenarthra, Cingulata)

ABSTRACT The comparative description of the most complete specimen of Dasypus punctatus (Xenarthra, Cingulata), from southeastern Brazil, reveals that the species differs from other Dasypodini by the numerous foramina it has in both buckler and movable osteoderms, providing the basis for the lectotype designation. This species was historically allocated to Propraopus, but the inclusiveness and monophyly of that genus are uncertain. A new phylogenetic analysis groups D. punctatus with the living species of Dasypus in a monophyletic clade for the genus, also supporting a Propraopus clade composed of P. sulcatus and the type species P. grandis. The palatal anatomy corroborates previously suggested affinities between D. kappleri and D. punctatus. On the contrary, the possible synonymy between P. grandis and P. sulcatus needs further investigation, given that they differed on a single character. As usual in cingulate systematics, characters related to osteoderm ornamentation proved essential to determine the relationships of taxa. However, their use requires careful sampling in order to account for intraspecific variation biases.

A new species of Dasypodidae (Xenarthra: Cingulata) from the late Miocene of northwestern South America: implications in the Dasypodini phylogeny and diversity

A new species of dasypodid armadillo (Xenarthra, Cingulata), Anadasypus aequatorianus, from the late Miocene of Ecuador is described. The remains were collected in sediments of the Letrero Formation, Nabón Basin, which is part of several intermontane basins related to Andean uplift. The genus represents the oldest record of Dasypodini, which also encompasses Propraopus (Pleistocene–early Holocene) and Dasypus (?Miocene–Recent). The new species is based on several osteoderms, which show more derived features than Anadasypus hondanus, from the middle Miocene of Colombia. In order to test the affinities of A. aequatorianus within Dasypodini, we conducted a cladistic analysis of 24 morphological characters for 10 taxa. The most parsimonious tree supports the generic attribution of the new species and places Anadasypus basal to Propraopus and Dasypus, agreeing with the stratigraphic evidence. The faunas from tropical Andean areas differ noticeably from the better-known assemblages of the classic South American sequences. In the case of dasypodines, their geochronological distribution shows that they were historically restricted to tropical and subtropical environments and the main cladogenetic events of the group probably occurred at lower latitudes. In this context, the taxon described herein fills important temporal and geographic gaps of early Neogene armadillos from intertropical areas.http://www.zoobank.org/urn:lsid:zoobank.org:pub:9DC76603-D831-4E68-BE55-90113228E0F4

A Late Cretaceous mammal from Brazil and the first radioisotopic age for the Bauru Group

In the last three decades, records of tribosphenidan mammals from India, continental Africa, Madagascar and South America have challenged the notion of a strictly Laurasian distribution of the group during the Cretaceous. Here, we describe a lower premolar from the Late Cretaceous Adamantina Formation, São Paulo State, Brazil. It differs from all known fossil mammals, except for a putative eutherian from the same geologic unity and Deccanolestes hislopi, from the Maastrichtian of India. The incompleteness of the material precludes narrowing down its taxonomic attribution further than Tribosphenida, but it is larger than most coeval mammals and shows a thin layer of parallel crystallite enamel. The new taxon helps filling two major gaps in the fossil record: the paucity of Mesozoic mammals in more northern parts of South America and of tribosphenidans in the Cretaceous of that continent. In addition, high-precision U-Pb geochronology provided a post-Turonian maximal age (≤87.8 Ma) for the type stratum, which is overlain by the dinosaur-bearing Marília Formation, constraining the age of the Adamantina Formation at the site to late Coniacian–late Maastrichtian. This represents the first radioisotopic age for the Bauru Group, a key stratigraphic unit for the study of Cretaceous tetrapods in Gondwana.

First confirmed records of the Pantanal Cat, Leopardus colocola braccatus (Cope, 1889), in the state of São Paulo, Brazil

The Pantanal Cat, Leopardus colocola braccatus, presents a broad distribution over several biomes in South America. However, the distribution of the species is based on a limited number of occurrences, and confirmed records of the species are scarce. Here, we present 2 confirmed records of Leopardus colocola braccatus from the state of São Paulo, southeast Brazil. Both records are juvenile individuals, 1 recorded in the municipality of Castilho and the other in Araçatuba. These São Paulo records expand the distribution of this uncommon felid to the most populous state of Brazil. This species is currently Data Deficient on the São Paulo Red List, and these new records may help with future assessments of the conservation status of this felid.