The role of ontogeny on character polarization in early dinosaurs: a new specimen from the Late Triassic of southern Brazil and its implications

Only recently, new ontogenetic series of early dinosaurs and related groups have been described. Here, we present an isolated immature dinosauriform femur from the Late Triassic of southern Brazil and investigate its influence on character polarization. Because the specimen shares a number of synapomorphies with Pampadromaeus barberenai, herein we postulate that it corresponds to a juvenile individual of that taxon. Accordingly, we investigate the morphological variation between juvenile and mature individuals of P. barberenai. Scoring these character states into a published phylogenetic data-set of Dinosauromorpha reveals that morphological variation is higher than that observed among closely-related taxa. Ontogenetic variation thus exerts influence on character polarization. In addition, modification of the scores affected by ontogeny produces different topologies, as noted by the reduction in both the number of most parsimonious trees and number of steps, and increased inclusivity of some clades and reduction of polytomies as well. Our study, together with other recent contributions, sheds light on the morphologic pathways seen during dinosauromorph ontogenetic development, which is crucial to more reliably assess phylogenetic reconstructions and macroevolutionary patterns of this widespread and successful group.     

A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina

Herrerasauridae comprises a basal clade of dinosaurs best known from the Upper Triassic of Argentina and Brazil, which have yielded remains of Herrerasaurus ischigualastensis and Staurikosaurus pricei, respectively. Systematic opinion regarding the position of Herrerasauridae at the base of Dinosauria has varied. Here we describe a new herrerasaurid, Sanjuansaurus gordilloi gen. n., sp. n., based on a partial skeleton from Carnian-age strata of the the Upper Triassic Ischigualasto Formation of northwestern Argentina. The new taxon is diagnosed by numerous features, including long, band-shaped and posterolaterally oriented transverse process on the posterior cervical vertebrae; neural spines of the sixth to eighth dorsal vertebrae, at least, bearing acute anterior and posterior processes; scapula and coracoid with everted lateral margins of the glenoid; and short pubis (63% of the femoral length). Phylogenetic analysis placed Sanjuansaurus within a monophyletic Herrerasauridae, at the base of Theropoda and including Herrerasaurus and Staurikosaurus. The presence of Sanjuansaurus at the base of the Ischigualasto Formation, along with other dinosaurs such as Herrerasaurus, Eoraptor, Panphagia, and Chromogisaurus suggests that saurischian dinosaurs in southwestern Pangea were already widely diversified by the late Carnian rather than increasing in diversity across the Carnian-Norian boundary.     

An unusual new archosauriform from the Middle–Late Triassic of southern Brazil and the monophyly of Doswelliidae

Until now the Doswelliidae was considered a monospecific family including Doswellia kaltenbachi from the Late Triassic of North America. The phylogenetic position of this taxon remained enigmatic until recently, when a sister‐group relationship with the Proterochampsidae was suggested. In the present contribution we describe the new doswelliid species Archeopelta arborensis gen. et sp. nov. from the Middle–Late Triassic of Brazil. A cladistic analysis recovered Archeopelta, Doswellia, and Tarjadia within a monophyletic group of basal archosauriforms, the Doswelliidae. The monophyly of this family is supported by the presence of osteoderm ornamentation that is coarse, incised, and composed of regular pits and the presence of an unornamented anterior articular lamina. Archeopelta is more closely related to Doswellia than to other archosauriforms by the presence of basipterygoid processes anterolaterally orientated, dorsal centra with a convex surface, width of the neural arch plus ribs of the first primordial sacral that are three times the length of the neural arch, and iliac blade laterally deflected, with strongly convex dorsal margin, and a length less than three times its height. The phylogenetic analysis indicates that Doswellidae is the closest large monophyletic entity to Archosauria, which achieved a wide palaeolatitudinal distribution during the late Middle and Late Triassic time span. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 839–871.     

Taxonomic and phylogenetic reassessment of the early neotheropod dinosaur Camposaurus arizonensis from the Late Triassic of North America

Abstract: Camposaurus arizonensis, a small theropod dinosaur from the early–middle Norian of Arizona (USA), is widely considered the oldest known neotheropod. However, despite its importance, Camposaurus is the subject of taxonomic and phylogenetic uncertainty and is often considered a nomen dubium, largely because of a fragmentary holotype. We here reassess the holotype of Camposaurus and identify two autapomorphies: the posterior edge of the tibial articular surface for the fibula offset as a sharp and prominent ridge and the absence of an anteriorly expanded medial condyle of the astragalus. We therefore consider Camposaurus to be a valid and diagnostic taxon of basal theropod dinosaur. For the first time, we include Camposaurus in a phylogenetic analysis, which confirms its neotheropod placement and recovers it as a close relative of Coelophysis rhodesiensis within Coelophysoidea sensu stricto. The position of Camposaurus as the oldest neotheropod provides an important calibration point, but necessitates long ghost lineages, indicating that our knowledge of the early evolutionary history of theropod dinosaurs is still patchy. Furthermore, our phylogenetic analysis recovers a polytomy at the base of Neotheropoda, as most parsimonious trees disagree in recovering a monophyletic or paraphyletic ‘traditional’ Coelophysoidea. This suggests that basal theropod phylogeny remains in a state of flux, and the monophyly of ‘traditional’ Coelophysoidea remains an open question.     

Systematics and evolutionary significance of the small Abrocomidae from the early Miocene of southern South America

Octodontoidea is the most species-rich clade among hystricomorph rodents, and has a fossil record going back to at least the late Oligocene. Affinities of fossils previous to the late Miocene differentiation of the extant families Abrocomidae, Echimyidae and Octodontidae are controversial, essentially because these fossils may share few apomorphies with modern species. In fact, pre-late Miocene representatives of Abrocomidae had not been recognised until very recently. Here we revise the early Miocene genus Acarechimys, originally assigned to Echimyidae, and alternatively to stem Octodontoidea or to Octodontidae. A systematic and parsimony-based phylogenetic analysis of the species traditionally included in Acarechimys showed that this genus is part of stem Abrocomidae. These results are primarily supported by morphology of the mandible and lower molars. Acarechimys is here restricted to three species, A. minutus, A. pulchellus and Acarechimys pascuali sp. nov., while another species, A. constans, is here transferred to a new abrocomid genus. The remaining species were nested within Octodontidae. According to these results, Abrocomidae might have been as diverse as its sister clade Octodontidae-Echimyidae during the late Oligocene–early Miocene. Extinction of this diversity would have resulted in marked loss of evolutionary history, with extant abrocomids being currently restricted to late-diverged euhypsodont representatives.     

Diet of prosauropod dinosaurs from the late Triassic and early Jurassic

Prosauropods were not scavenger-predators, rather they were the dominant large terrestrial herbivores during the late Triassic and early Jurassic. The herbivorous adaptations of anchisaurids include spatulate teeth with anteroposteriorly expanded crowns (maximum width apical to base of crown) which are obliquely inclined with respect to the jaws so each slightly overlaps the tooth behind it, and which have coarse marginal serrations at 45° to the cutting edges. Most of the teeth of yunnanosaurids lack serrations and resemble those of sauropod dinosaurs in form and in having self-sharpening surfaces, formed by tooth-to-tooth wear, which increased the efficiency of dealing with more resistant plant material. Anchisaurids and yunnanosaurids had a ventrally set jaw articulation; the teeth and skull of melanorosaurids are unknown. All prosauropods were high browsers that extended the feeding range with a long neck and tripodal feeding (long hindlimbs and stout tail for support). They used herding and the enormous claw on the pollex for defense, and probably had a muscular gastric mill with stones that was used for grinding the food. They account for at least 95% of the biomass in their respective faunas.     

Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon

Sauropodomorph dinosaurs originated in the Southern Hemisphere in the Middle or Late Triassic and are commonly portrayed as spreading rapidly to all corners of Pangaea as part of a uniform Late Triassic to Early Jurassic cosmopolitan dinosaur fauna. Under this model, dispersal allegedly inhibited dinosaurian diversification, while vicariance and local extinction enhanced it. However, apomorphy-based analyses of the known fossil record indicate that sauropodomorphs were absent in North America until the Early Jurassic, reframing the temporal context of their arrival. We describe a new taxon from the Kayenta Formation of Arizona that comprises the third diagnosable sauropodomorph from the Early Jurassic of North America. We analysed its relationships to test whether sauropodomorphs reached North America in a single sweepstakes event or in separate dispersals. Our finding of separate arrivals by all three taxa suggests dispersal as a chief factor in dinosaurian diversification during at least the early Mesozoic. It questions whether a 'cosmopolitan' dinosaur fauna ever existed, and corroborates that vicariance, extinction and dispersal did not operate uniformly in time or under uniform conditions during the Mesozoic. Their relative importance is best measured in narrow time slices and circumscribed geographical regions.     

Morphology of the endocranial cavities of Campinasuchus dinizi (Crocodyliformes: Baurusuchidae) from the Upper Cretaceous of Brazil

Two specimens of Campinasuchus dinizi (CPPLIP 1319 and CPPLIP 1360) belonging to Baurusuchidae (Crocodyliformes, Notosuchia) from the Upper Cretaceous Bauru Group of Minas Gerais state (Brazil) were scanned in a Toshiba Aquilion 64 CT machine. Based on these data, it was possible to identify and reconstruct the paranasal sinuses, the nasal cavity proper, the nasopharyngeal duct, the encephalon, the paratympanic sinuses, and the semicircular canals of the inner ear. The paranasal sinuses present similar morphology to those of other mesoeucrocodylians, especially eusuchians. The nasal cavity proper occupies the entire rostral region, with an expansion in the olfactory region. The expansion in the nasal cavity is present in other notosuchians and theropod dinosaurs (e.g., Tyrannosaurus rex Osborn, 1905), but less developed in aquatic crocodilians, which may indicate an olfactory acuity related to terrestrial habits. The encephalon is similar in shape to that of other mesoeucrocodylians. The rostral semicircular canal is smaller than the caudal one, differing from most mesoeucrocodylians. The paratympanic sinuses are more developed in C. dinizi than in eusuchians, being more similar to Tyrannosaurus rex. Campinasuchus dinizi presents few variations in the internal structures of the skull in relation to taxa with different ecological niches, probably indicating that ecological factors do not strongly influence the morphology of these structures.     

Four new species of Cerambycidae (Coleoptera) from Brazil and updated identification keys

Four new species of longhorn beetles are described from Brazil: Coleoxestia diamantina n. sp. (Cerambycinae, Cerambycini), from Bahia; Mirador bravoi n. sp. (Cerambycinae, Ectenessini), from Bahia; Compsibidion antonietae n. sp. (Cerambycinae, Neoibidionini), from Goiás, Bahia and São Paulo; and Amphicnaeia quadrifasciata n. sp. (Lamiinae, Apomecynini) from Bahia. Coleoxestia diamantina and Compsibidion antonietae are included in previous keys.     

A new oligolectic bee species of the genus Rhophitulus Ducke (Hymenoptera,Andrenidae) from South Brazil

The genus Rhophitulus Ducke, 1907 is a large and complex group of bees of the tribe Protandrenini comprising small, slender, mostly black ground-nesting species that are restricted to South America. We describe a new species of Rhophitulus from Parque Nacional São Joaquim, Urubici, state of Santa Catarina, Brazil. Rophitulus ater sp. nov. is distinctive and easily distinguished from other species of the genus by a unique combination of morphological characters in both sexes, but especially by the following: dull black body, coarsely and densely punctate integument, basal area of metapostnotum depressed and areolate rugose, posterior margin of hind tibia and pygidial fimbria of female with blackish pilosity, and characters of the male genitalia with hidden sterna. The new species is closely associated with Blumenbachia catharinensis (Loasaceae), which is restricted to cloud forest of the southeastern rim of Serra Geral. Flowers of B. catharinensis are pollen and nectar resources and mating sites for the new species.     

Two new species of Vellozia (Velloziaceae) from Minas Gerais, Brazil

Two new species of Vellozia from the Espinhaco range in the State of Minas Gerais, Brazil, are described and their taxonomic relationships are considered. A discussion of their geographical distribution and an account of their leaf anatomy is provided.     

A new non-mammalian eucynodont from the Chinle Formation (Triassic: Norian), and implications for the early Mesozoic equatorial cynodont record

The Upper Triassic tetrapod fossil record of North America features a pronounced discrepancy between the assemblages of present-day Virginia and North Carolina relative to those of the American Southwest. While both are typified by large-bodied archosaurian reptiles like phytosaurs and aetosaurs, the latter notably lacks substantial representation of mammal relatives, including cynodonts. Recently collected non-mammalian eucynodontian jaws from the middle Norian Blue Mesa Member of the Chinle Formation in northeastern Arizona shed light on the Triassic cynodont record from western equatorial Pangaea. Importantly, they reveal new biogeographic connections to eastern equatorial Pangaea as well as southern portions of the supercontinent. This discovery indicates that the faunal dissimilarity previously recognized between the western and eastern portions of equatorial Pangaea is overstated and possibly reflects longstanding sampling biases, rather than a true biogeographic pattern.     

Two new species of Alstroemeria L. (Alstroemeriaceae) from Brazil

Alstroemeria hygrophila andA. orchidioides are both described as new from the state of Goiás (including Distrito Federal) in Brazil.Alstroemeria hygrophila is a cerrado bog-dwelling species that grows semi-epiphytically on the culms of a sedge. The vegetative stems of this species characteristically zig-zag between the pseudonodes. Like other wetlandAlstroemeria in Brazil (e.g.,A. apertiflora, A. isabellana, andA. sellowiana),A. hygrophila has wiry stems bearing narrow, lanceolate, nonresupinate leaves, and does not form root tubers.Alstroemeria orchidioides is a hysteranthus forest understory species with large vegetative leaves aggregated at the apex of the stems. The leaves on flowering stems are reduced to scarious bract-like scales. Its flowers are a pale, nearly white, greenish yellow, a color not reported in any other Brazilian species. Both species have 2n=16 chromosomes.     

Pindamoraria boraceiae, a new genus and species of freshwater Canthocamptidae (Copepoda, Harpacticoida) from Brazil

Members of a new genus and species of harpacticoid copepod crustacean appeared in samples from semi-terrestrial (moist arboreal mosses, wet soil) and aquatic (bromeliad tanks, Sphagnum moss, rock pools, stream) habitats in a remnant of the Atlantic Forest in south-eastern Brazil. The new taxon, for which we propose the name Pindamoraria boraceiae sp. nov. , is distinguished by a unique combination of characters, in particular the segmentation and setation pattern of legs 1–4 in both sexes, the structure of leg 5 in the female, and the strongly modified claw of the maxilliped in the male. It most resembles the canthocamptid genera Moraria , Pseudomoraria , Morariopsis and Paramorariopsis . Both previous records of species of Moraria from South America refer to members of Antarctobiotus , which is not considered a member of the Moraria group: Moraria (Kuehneltiella) neotropica Löffler has previously been transferred to Antarctobiotus ; and we propose herein the transfer of Moraria kummeroworum Ebert & Noodt to Antarctobiotus as well. In the New World, the genus Moraria extends only as far south as Honduras; and Pseudomoraria , Morariopsis and Paramorariopsis are Old World genera. The new species from Brazil is therefore the only member of the Moraria group known from South America.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 139, 81–92.     

Filograna (colonial serpulid worm tubes) from Upper Triassic (Norian) reef boulders of Taurus Mts. (southern Turkey)

Two colonial serpulid worm tubes—Filograna taurica n. sp. and Filograna serialis n. sp.—from the Upper Triassic (Norian) reef boulders occurring in Taurus Mts. (south Turkey) are described. As bafflers, both species of Filograna build microbioherms reaching dimensions of up to 15 cm. Both species were not known either in Turkey or in any other Triassic localities of the Tethyan realm.