DOCSLIB.ORG

Homology of Facial Structures in Extant Archosaurs (Birds and Crocodilians), with Special Reference to Paranasal Pneumaticity and Nasal Conchae LAWRENCE M

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

JOURNAL OF MORPHOLOGY 225269-327 (1995) Homology of Facial Structures in Extant Archosaurs (Birds and Crocodilians), With Special Reference to Paranasal Pneumaticity and Nasal Conchae LAWRENCE M. WITMER Department of Cell Biology and Anatomy, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department ofdnatomy, New York College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, New York 11568 ABSTRACT Homology of virtually all major components of facial anatomy is assessed in Archosauria in order to address the function of the antorbital cavity, an enigmatic structure that is diagnostic for the group. Proposed functions center on its being a housing for a gland, a muscle, or a paranasal air sinus. Homology is approached in the context of the Extant Phylogenetic Bracket method of reconstructing unpreserved aspects of extinct organisms. Facial anatomy and its ontogeny was studied in extant archosaurs (birds and crocodilians)to determine the osteological correlates of each soft-tissue compo- nent; resemblances between birds and crocodilians comprised the similarity test of homology. The congruence test of homology involved surveying phyloge- netically relevant fossil archosaurs for these bony signatures. The facial anatomy of extant birds and crocodilians is examined in detail to provide background and to discover those apomorphic aspects that contribute to the divergent specialization of these two groups and thus obscure homologies. Birds apomor- phically show enlarged eyeballs, expanded nasal vestibules, and reduced maxil- lae, whereas crocodilian faces are dorsoventrally flattened (due to nasal rota- tion) and elongated. Most facial attributes of archosaurs are demonstrably homologous and in fact characterize much more inclusive groups. Special emphasis has been placed on the nasal conchae and paranasal air sinuses. Within Amniota, the following conchal structures are homologous, and all others are neomorphs: avian caudal concha, crocodilian concha + preconcha, Sphenodon caudal concha, squamate concha, and probably the mammalian crista semicircularis. The avian antorbital paranasal air sinus is homologous with the crocodilian caviconchal sinus; the maxillary sinus of placental mam- mals is not homologous with the archosaurian paranasal sinus. With regard to the function of the antorbital cavity, archosaurs possess homologous nasal glands, dorsal pterygoideus muscles, and paranasal air sinuses, but the osteo- logical correlates of only the paranasal sinus involve the antorbital fenestrae and fossae. Thus, the antorbital cavity is best interpreted as principally a pneumatic structure. o 1995 Wiley-Liss, Inc. The age-old image of a tiny plover calmly vertebrates living today, during the Mesozoic gleaning the leeches from within the gaping Era extinct archosaurs (i.e., nonavian dino- mouth of a crocodile hardly suggests the no- saurs, pterosaurs, and a variety of early tion of any kinship between these two very forms) radiated into virtually all habitats and different vertebrates. However, among mod- by all measures were the dominant terres- ern vertebrates, birds and crocodilians are trial vertebrates. As a result of this radiation, indeed sister taxa, representing the only sur- viving clades of Archosauria. Although ex- Address reprint requests to Lawrence M.Witmer, Department tant archosaurs, with their 10,000 species, of Biological Sciences and College of Osteopathic Medicine, Ohio remain the most diverse group of terrestrial University,Athens, OH 45701. email: [email protected] o 1995 WILEY-LISS,INC 270 L.M. WITMER archosaurs present an extraordinary diver- called the antorbital fenestra and cavity, re- sity of skull morphology. The pattern of ar- spectively (Witmer, '94). The antorbital cav- chosaur phylogeny among extinct as well as ity (defined below) is ubiquitous in at least living members is beginning to be unraveled the basal members of all clades of archosaurs (Gauthier, '86; Sereno, '86, '91; Gauthier et and is a synapomorphy of a slightly more al., '88a; Benton and Clark, '88; Cracraft, inclusive group (Archosauriformes; Fig. 1; '88; Norell, '89; Novas, '92; Clark et al., '93; Gauthier et al., '88a; Benton and Clark, '88). Parrish, '93), and we are now in a good In some archosaurs (e.g., some theropod dino- position to understand the evolution of archo- saurs) the antorbital cavity is very promi- saur craniofacial adaptation. nent, occupying somewhat more than half An important component of the diversity the total skull length, whereas in others (e.g., in skull morphology in archosaurs pertains some ornithischian dinosaurs) it is all but to the facial skeleton, in particular to an lost (see Witmer, in press). Ironically, the opening and space in the side of the snout function (and hence soft-tissue relations) of Abbreviations a o cav cavitas antorbitalis nldu ductus nasolacrimalis a o fos fossa antorbitalis n 1 du ost ostium nasale, ductus nasolacrimalis a o sin sinus antorbitalis n 1gl fos fossa glandulae nasolacrimalis a o sin ost ostium, sinus antorbitalis npdu ductus nasopharyngeus acc cav cavitas accessorius nar apertura nasi ossea (= naris) ad co aditus conchae nas 0s nasale antorb sin sinus antorbitalis nas gl glandula nasalis ap cavico rec apertura recessus caviconchalis nas gl du ductus glandulae nasalis apnldu apertura ductus nasolacrimalis nas gl gr groove for glandula nasalis atr tur atrioturbinal nas tur nasoturbinal caud co concha nasalis caudalis neurovas neurovasculature caudolat rec recessus caudolateralis neurovas sp neurovascular space cav co cavum conchae olf bulb rec recessus bulbus olfactorius cavico rec recessus caviconchalis ophth N n. ophthalmicus cavico sin sinus caviconcbalis orb orbita cavico sin ost ostium, sinus caviconchalis Pal 0s palatinum cec rec recessus caeci pal bulge bulge of 0s palatinum ch choana pal pr rnax processus palatinus, 0s maxillare CNP cavum nasi proprium pal sin sinus palatinus CN Vi n. ophthalmicus Pare cartilago paranasalis co concha nasalis Pmx 0s premaxillare cr sem crista semicircularis pmx div diverticulum premaxillare eth tur ethmoturbinal pn for foramen pneumaticurn ex a o fen fenestra antorbitalis externa PO vest rec recessus postvestibularis ex add m. adductor mandibulae externus PO vest sin sinus postvestibularis ex co rec recessus extraconchalis postco postconcha fen nar fenestra narina postco cav cavitas postconchalis font a o fonticulus antorbitalis preco preconcha for epiph foramen epiphaniale preco rec recessus preconchalis fr 0s frontale Prf 0s prefrontale in a o fen fenestra antorbitalis interna prf rec recessus prefrontalis jo organum vomeronasale ( = Jacobson's prim ch choana prima (= primary choana) organ) PtC cartilago parietotectalis jug 0s jugale pter 0s pterygoideum jug bar arcus jugalis pter dor m. pterygoideus, pars dorsalis lac 0s lacrimale Ram lat nas ramus lateralis nasi. n. oDhthalmicus lac cav cavitas lacrimalis Ram med nas ramus medialis nasi, n. opbthalmicus la div diverticulum lacrimale rec du np recessus ducti nasopharyngei lam orb lamina orbitonasalis roof nas cap roof of cartilaginous nasal capsule lat Gr laterale Grenzfalte root co root of concha LTR lamina transversalis rostralis ros co concha nasalis rostralis mand mandibula scl sclera mand N n. mandibularis sec ch choana secundaria (= secondary choana) max 0s maxillare SeP septum male max N n. maxillaris suborb fen fenestra suborbitalis rnax sin ost ostium sinus maxillaris sep sulc sulcus septalis max tur maxilloturbinal tect nas tectum nasi mes 0s mesethmoidale vest vestibulum nasi mid co concha nasalis media vom vomer musc fos fossa muscularis, 0spalatinum FACIAL HOMOLOGIES IN ARCHOSAURS 271 a o cav lac Comparison of birds and crocodilians within the context of both amniote and archo- saur phylogeny also provides the opportunity to study a striking example of divergent spe- cialization superimposed upon a shared, in- herited ground plan. Crocodilians have a “pri- mordial” look about them and are commonly portrayed as living fossils little changed since their origin over 200 million years ago (Romer, ’66).Indeed, they retain manyprimi- tive features such as the presence of teeth “\ and most of the original complement of skull max pter Pal bones. However, modern crocodilians exhibit numerous apomorphies in all regions of the Fig. 1. Eupurkeria capensis, a basal archosauriform skull (Langston, ’73) and particularly in the from the Triassic of South Africa, in left lateral view, face, probably in association with skull flat- showing the antorbital cavity within the lateral aspect of the snout. Modified after Ewer (’65) and Witmer (’87). tening and formation of a long nasopharyn- geal duct. On the other hand, birds, despite being highly modified for flight, show some aspects of skull morphology that are actually the cavity is enigmatic and has been a matter primitive in comparison to crocodilians. For of some dispute (see Walker, ’61; Ewer, ’65; example, although birds apomorphically have Osmolska, ’85; Witmer, ’87; see Witmer, in press), the three major hypotheses being that lost several skull bones in association with the cavity housed 1) a gland, 2) a portion of the evolution of cranial kinesis, they primi- the jaw musculature, or 3) a paranasal air tively retain an external antorbital fenestra. sinus. The glandular hypothesis never has In fact, this mosaic pattern is a good illustra- had many adherents, whereas the muscular tion of why characters, not taxa, should be hypothesis has been by far the most popular
Recommended publications
  • 8. Archosaur Phylogeny and the Relationships of the Crocodylia

    8. Archosaur Phylogeny and the Relationships of the Crocodylia

    8. Archosaur phylogeny and the relationships of the Crocodylia MICHAEL J. BENTON Department of Geology, The Queen's University of Belfast, Belfast, UK JAMES M. CLARK* Department of Anatomy, University of Chicago, Chicago, Illinois, USA Abstract The Archosauria include the living crocodilians and birds, as well as the fossil dinosaurs, pterosaurs, and basal 'thecodontians'. Cladograms of the basal archosaurs and of the crocodylomorphs are given in this paper. There are three primitive archosaur groups, the Proterosuchidae, the Erythrosuchidae, and the Proterochampsidae, which fall outside the crown-group (crocodilian line plus bird line), and these have been defined as plesions to a restricted Archosauria by Gauthier. The Early Triassic Euparkeria may also fall outside this crown-group, or it may lie on the bird line. The crown-group of archosaurs divides into the Ornithosuchia (the 'bird line': Orn- ithosuchidae, Lagosuchidae, Pterosauria, Dinosauria) and the Croco- dylotarsi nov. (the 'crocodilian line': Phytosauridae, Crocodylo- morpha, Stagonolepididae, Rauisuchidae, and Poposauridae). The latter three families may form a clade (Pseudosuchia s.str.), or the Poposauridae may pair off with Crocodylomorpha. The Crocodylomorpha includes all crocodilians, as well as crocodi- lian-like Triassic and Jurassic terrestrial forms. The Crocodyliformes include the traditional 'Protosuchia', 'Mesosuchia', and Eusuchia, and they are defined by a large number of synapomorphies, particularly of the braincase and occipital regions. The 'protosuchians' (mainly Early *Present address: Department of Zoology, Storer Hall, University of California, Davis, Cali- fornia, USA. The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds (ed. M.J. Benton), Systematics Association Special Volume 35A . pp. 295-338. Clarendon Press, Oxford, 1988.
  • A Phylogenetic Analysis of the Basal Ornithischia (Reptilia, Dinosauria)

    A Phylogenetic Analysis of the Basal Ornithischia (Reptilia, Dinosauria)

    A PHYLOGENETIC ANALYSIS OF THE BASAL ORNITHISCHIA (REPTILIA, DINOSAURIA) Marc Richard Spencer A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements of the degree of MASTER OF SCIENCE December 2007 Committee: Margaret M. Yacobucci, Advisor Don C. Steinker Daniel M. Pavuk © 2007 Marc Richard Spencer All Rights Reserved iii ABSTRACT Margaret M. Yacobucci, Advisor The placement of Lesothosaurus diagnosticus and the Heterodontosauridae within the Ornithischia has been problematic. Historically, Lesothosaurus has been regarded as a basal ornithischian dinosaur, the sister taxon to the Genasauria. Recent phylogenetic analyses, however, have placed Lesothosaurus as a more derived ornithischian within the Genasauria. The Fabrosauridae, of which Lesothosaurus was considered a member, has never been phylogenetically corroborated and has been considered a paraphyletic assemblage. Prior to recent phylogenetic analyses, the problematic Heterodontosauridae was placed within the Ornithopoda as the sister taxon to the Euornithopoda. The heterodontosaurids have also been considered as the basal member of the Cerapoda (Ornithopoda + Marginocephalia), the sister taxon to the Marginocephalia, and as the sister taxon to the Genasauria. To reevaluate the placement of these taxa, along with other basal ornithischians and more derived subclades, a phylogenetic analysis of 19 taxonomic units, including two outgroup taxa, was performed. Analysis of 97 characters and their associated character states culled, modified, and/or rescored from published literature based on published descriptions, produced four most parsimonious trees. Consistency and retention indices were calculated and a bootstrap analysis was performed to determine the relative support for the resultant phylogeny. The Ornithischia was recovered with Pisanosaurus as its basalmost member.
  • Perinate and Eggs of a Giant Caenagnathid Dinosaur from the Late Cretaceous of Central China

    Perinate and Eggs of a Giant Caenagnathid Dinosaur from the Late Cretaceous of Central China

    ARTICLE Received 29 Jul 2016 | Accepted 15 Feb 2017 | Published 9 May 2017 DOI: 10.1038/ncomms14952 OPEN Perinate and eggs of a giant caenagnathid dinosaur from the Late Cretaceous of central China Hanyong Pu1, Darla K. Zelenitsky2, Junchang Lu¨3, Philip J. Currie4, Kenneth Carpenter5,LiXu1, Eva B. Koppelhus4, Songhai Jia1, Le Xiao1, Huali Chuang1, Tianran Li1, Martin Kundra´t6 & Caizhi Shen3 The abundance of dinosaur eggs in Upper Cretaceous strata of Henan Province, China led to the collection and export of countless such fossils. One of these specimens, recently repatriated to China, is a partial clutch of large dinosaur eggs (Macroelongatoolithus) with a closely associated small theropod skeleton. Here we identify the specimen as an embryo and eggs of a new, large caenagnathid oviraptorosaur, Beibeilong sinensis. This specimen is the first known association between skeletal remains and eggs of caenagnathids. Caenagnathids and oviraptorids share similarities in their eggs and clutches, although the eggs of Beibeilong are significantly larger than those of oviraptorids and indicate an adult body size comparable to a gigantic caenagnathid. An abundance of Macroelongatoolithus eggs reported from Asia and North America contrasts with the dearth of giant caenagnathid skeletal remains. Regardless, the large caenagnathid-Macroelongatoolithus association revealed here suggests these dinosaurs were relatively common during the early Late Cretaceous. 1 Henan Geological Museum, Zhengzhou 450016, China. 2 Department of Geoscience, University of Calgary, Calgary, Alberta, Canada T2N 1N4. 3 Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China. 4 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9. 5 Prehistoric Museum, Utah State University, 155 East Main Street, Price, Utah 84501, USA.
  • Vorläufige Mitteilung Über Einen Neuen Phytosaurus-Schädel Aus Dem Schwäbischen Keuper

    Vorläufige Mitteilung Über Einen Neuen Phytosaurus-Schädel Aus Dem Schwäbischen Keuper

    — © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/;www.zobodat.at F. v. Huene, Vorläufige Mitteilung etc. 583 Vorläufige Mitteilung über einen neuen Phytosaurus-Schädel aus dem schwäbischen Keuper. Von F. v. Huene in Tübingen. Mit 7 Textfiguren. Im Jahre 1905 erhielt das geologische Museum in Tübingen aus dem Stubensandstein des Steinbruches der Unteren Mühle bei Trossingen (im südwestlichen Württemberg) einen sehr großen Phgtosaurus-SchÄiel, dessen Präparation erst im Herbst 1908 voll- endet wurde. Von Herrn Prof. Koken wurde mir freundlichst die Bearbeitung desselben übertragen. Der Schädel gehört zu Pliytosanrus Plieningeri H. v. Meyer, er ist wesentlich größer als die bisher vorhandenen Exemplare, er übertrifft auch alle sonst bekannten Pliytosanrier an Größe (103 cm Länge). Die Erhaltung ist eine vorzügliche, es ließen sich alle Nähte sehr genau verfolgen. Namentlich gelang es auch durch mühsame Präparation die Gaumenknochen von beiden Seiten freizulegen. , Der Unterkiefer ist nicht vorhanden. Es sollen hier nur einige der wichtigsten Punkte heraus- gegriffen werden : 1. Das Vorhandensein von Septomaxillaria. Schon H. v. Meyer war 1862 (Paläontogr. 10. p. 242 und Taf. 41 Fig. 2) an seinem Bdodon planirostris aufgefallen, daß „der innere Teil der Nasenbeine, welcher von dem äußeren durch die vom vorderen (Nasen-)Locliwinkel nach vorne verlaufende Naht getrennt wird, dreizinkig in den Zwischen- kiefer eingreift“. Drei Jahre später (Paläontogr. 14. p. 106, Taf. 25) nennt derselbe diesen „inneren Teil der Nasenbeine“ zögernd „ein überzähliges Knochenpaar“. Von dieser Stelle hat auch Koken (Paläont. Abh. 3. 1886. p. 404 [96]) ohne eigene Anschauung dasselbe übernommen. Alle anderen Beobachter haben — soweit ich mich in der Literatur davon überzeugen konnte - diese meist deutlich sichtbaren Suturen , weil sie unverständlich schienen, völlig ignoriert.
  • Cranial Anatomy of Allosaurus Jimmadseni, a New Species from the Lower Part of the Morrison Formation (Upper Jurassic) of Western North America

    Cranial Anatomy of Allosaurus Jimmadseni, a New Species from the Lower Part of the Morrison Formation (Upper Jurassic) of Western North America

    Cranial anatomy of Allosaurus jimmadseni, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America Daniel J. Chure1,2,* and Mark A. Loewen3,4,* 1 Dinosaur National Monument (retired), Jensen, UT, USA 2 Independent Researcher, Jensen, UT, USA 3 Natural History Museum of Utah, University of Utah, Salt Lake City, UT, USA 4 Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA * These authors contributed equally to this work. ABSTRACT Allosaurus is one of the best known theropod dinosaurs from the Jurassic and a crucial taxon in phylogenetic analyses. On the basis of an in-depth, firsthand study of the bulk of Allosaurus specimens housed in North American institutions, we describe here a new theropod dinosaur from the Upper Jurassic Morrison Formation of Western North America, Allosaurus jimmadseni sp. nov., based upon a remarkably complete articulated skeleton and skull and a second specimen with an articulated skull and associated skeleton. The present study also assigns several other specimens to this new species, Allosaurus jimmadseni, which is characterized by a number of autapomorphies present on the dermal skull roof and additional characters present in the postcrania. In particular, whereas the ventral margin of the jugal of Allosaurus fragilis has pronounced sigmoidal convexity, the ventral margin is virtually straight in Allosaurus jimmadseni. The paired nasals of Allosaurus jimmadseni possess bilateral, blade-like crests along the lateral margin, forming a pronounced nasolacrimal crest that is absent in Allosaurus fragilis. Submitted 20 July 2018 Accepted 31 August 2019 Subjects Paleontology, Taxonomy Published 24 January 2020 Keywords Allosaurus, Allosaurus jimmadseni, Dinosaur, Theropod, Morrison Formation, Jurassic, Corresponding author Cranial anatomy Mark A.
  • A Late Cretaceous Diversification of Asian Oviraptorid Dinosaurs

    A Late Cretaceous Diversification of Asian Oviraptorid Dinosaurs

    www.nature.com/scientificreports OPEN A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species Received: 10 March 2016 Accepted: 06 October 2016 preserved in an unusual posture Published: 10 November 2016 Junchang Lü1, Rongjun Chen2, Stephen L. Brusatte3, Yangxiao Zhu2 & Caizhi Shen1 Oviraptorosaurs are a bizarre group of bird-like theropod dinosaurs, the derived forms of which have shortened, toothless skulls, and which diverged from close relatives by developing peculiar feeding adaptations. Although once among the most mysterious of dinosaurs, oviraptorosaurs are becoming better understood with the discovery of many new fossils in Asia and North America. The Ganzhou area of southern China is emerging as a hotspot of oviraptorosaur discoveries, as over the past half decade five new monotypic genera have been found in the latest Cretaceous (Maastrichtian) deposits of this region. We here report a sixth diagnostic oviraptorosaur from Ganzhou, Tongtianlong limosus gen. et sp. nov., represented by a remarkably well-preserved specimen in an unusual splayed-limb and raised- head posture. Tongtianlong is a derived oviraptorid oviraptorosaur, differentiated from other species by its unique dome-like skull roof, highly convex premaxilla, and other features of the skull. The large number of oviraptorosaurs from Ganzhou, which often differ in cranial morphologies related to feeding, document an evolutionary radiation of these dinosaurs during the very latest Cretaceous of Asia, which helped establish one of the last diverse dinosaur faunas before the end-Cretaceous extinction. Oviraptorosaurs are some of the most unusual dinosaurs. These bird-like, feathered theropods diverged dra- matically from their close cousins, evolving shortened toothless skulls with a staggering diversity of pneumatic cranial crests in derived forms1.
  • Heptasuchus Clarki, from the ?Mid-Upper Triassic, Southeastern Big Horn Mountains, Central Wyoming (USA)

    Heptasuchus Clarki, from the ?Mid-Upper Triassic, Southeastern Big Horn Mountains, Central Wyoming (USA)

    The osteology and phylogenetic position of the loricatan (Archosauria: Pseudosuchia) Heptasuchus clarki, from the ?Mid-Upper Triassic, southeastern Big Horn Mountains, Central Wyoming (USA) † Sterling J. Nesbitt1, John M. Zawiskie2,3, Robert M. Dawley4 1 Department of Geosciences, Virginia Tech, Blacksburg, VA, USA 2 Cranbrook Institute of Science, Bloomfield Hills, MI, USA 3 Department of Geology, Wayne State University, Detroit, MI, USA 4 Department of Biology, Ursinus College, Collegeville, PA, USA † Deceased author. ABSTRACT Loricatan pseudosuchians (known as “rauisuchians”) typically consist of poorly understood fragmentary remains known worldwide from the Middle Triassic to the end of the Triassic Period. Renewed interest and the discovery of more complete specimens recently revolutionized our understanding of the relationships of archosaurs, the origin of Crocodylomorpha, and the paleobiology of these animals. However, there are still few loricatans known from the Middle to early portion of the Late Triassic and the forms that occur during this time are largely known from southern Pangea or Europe. Heptasuchus clarki was the first formally recognized North American “rauisuchian” and was collected from a poorly sampled and disparately fossiliferous sequence of Triassic strata in North America. Exposed along the trend of the Casper Arch flanking the southeastern Big Horn Mountains, the type locality of Heptasuchus clarki occurs within a sequence of red beds above the Alcova Limestone and Crow Mountain formations within the Chugwater Group. The age of the type locality is poorly constrained to the Middle—early Late Triassic and is Submitted 17 June 2020 Accepted 14 September 2020 likely similar to or just older than that of the Popo Agie Formation assemblage from Published 27 October 2020 the western portion of Wyoming.
  • THE GENERA of REPTILES. By

    THE GENERA of REPTILES. By

    T he Genera of Re pt il e s. By BARON FRANCIS NOPCSA (Budapest). (Eingelangt am 11. Mai 1927.) Among all the Paleontologists living none has dealt with the recent and fossil reptiles with a wider grasp than Prof. L. D o l l o and at his anniversary it seems quite appropriate to review their whole array. The classification used in the following enumeration of all genera of reptiles is much the same as in my hook „Die Familien der Reptilien“; at this instance however an effort has been made to give a precise definition of every systematic unit. Alteration of the classification became necessary among the Dino- cephalians, the Nothosaurians, the Lacertilians (called here Sauroidea), the Coelurosauroidea and the Crocodilia. The new classification of the Sauroidea is intermediate between the classifications proposed by B o u l e n g e r and C a m p . Naturally as a rule only those fossil genera are referred to, that are more than simple catalogue numbers that facilitate the finding of the respective piece in a collection; indeterminable problematic genera of small interest have mostly been omitted. Extinct units and genera are marked in the lists with a cross ("j*). Difficulties of classification have been encountered in the Lacertilia and Ophidia, for in the new system the conventional families of recent Lizards and Serpents has been given subfamily rank and conse­ quently the different recent subfamilies had to be dropped. Instead of these subfamilies the minor units were separated by greek letters. — The tedious and complicated revision of the genera of recent Lizards and Snakes was done by Prof.
  • Taxonomy, Cranial Morphology, and Relationships of Parrot-Beaked Dinosaurs (Ceratopsia: Psittacosaurus)

    Taxonomy, Cranial Morphology, and Relationships of Parrot-Beaked Dinosaurs (Ceratopsia: Psittacosaurus)

    2 Taxonomy, Cranial Morphology, and Relationships of Parrot-Beaked Dinosaurs (Ceratopsia: Psittacosaurus) PAUL C. SERENO in 1922, well-preserved fossils of the first parrot- (Coombs 1980, 1982). For many years, Osborn’s two brief beaked dinosaur were discovered in Early Cretaceous notes on P. mongoliensis (Osborn 1923, 1924) and a descrip- horizons in the Gobi Desert of Mongolia. Now referred to tion of P. sinensis (Young 1958) provided most of the informa- a single species, Psittacosaurus mongoliensis, these remains tion available on psittacosaur morphology. include a growth series from hatchlings to adults. In sub- Recent Work. Sereno (1987) provided an overview of psit- sequent years, 15 species have been added to the genus tacosaur morphology. Portions of this dissertation were pub- Psittacosaurus and a second genus, Hongshanosaurus, was lished, including the description of two new species (P. meiley- recently described, all from Early Cretaceous rocks in ingensis, P. xinjiangensis; Sereno and Zhao 1988; Sereno et al. Asia. Although the second genus and about one-half of 1988), the synonomy of several poorly known species (Sereno the species attributed to Psittacosaurus are potentially in- 1990a), and an overview of the morphology of the clade Psit- valid, Psittacosaurus remains the most species-rich dino- tacosauridae (Sereno 1990b). Although most of this overview saurian genus, with interspecific variation concentrated can be found in You and Dodson (2004), reference is made in the skull and dentition. This paper reviews evidence only to the original source (Sereno 1990b). differentiating the named genera and species of psit- Russian psittacosaurs, including a partial skull first reported tacosaurs, outlines major cranial changes in a growth se- by Rozhdestvensky (1955, 1960) at Shestakovo in Siberia, be- ries from hatchling to adult in Psittacosaurus came the subject of a dissertation by Xijin Zhao under his mongoliensis, and provides evidence of two species direction.
  • A New Phylogenetic Analysis of Phytosauria (Archosauria: Pseudosuchia) with the Application of Continuous and Geometric Morphometric Character Coding

    A New Phylogenetic Analysis of Phytosauria (Archosauria: Pseudosuchia) with the Application of Continuous and Geometric Morphometric Character Coding

    A new phylogenetic analysis of Phytosauria (Archosauria: Pseudosuchia) with the application of continuous and geometric morphometric character coding Andrew S. Jones and Richard J. Butler School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK ABSTRACT Phytosauria is a clade of large, carnivorous, semi-aquatic archosauromorphs which reached its peak diversity and an almost global distribution in the Late Triassic (c. 230–201 Mya). Previous phylogenetic analyses of Phytosauria have either focused primarily on the relationships of specific subclades, or were limited in taxonomic scope, and no taxonomically comprehensive dataset is currently available. We here present the most taxonomically comprehensive cladistic dataset of phytosaurs to date, based on extensive first-hand study, identification of novel characters and synthesis of previous matrices. This results in an almost twofold increase in phylogenetic information scored per taxon over previous analyses. Alongside a traditional discrete character matrix, three variant matrices were analysed in which selected characters were coded using continuous and landmarking methods, to more rigorously explore phytosaur relationships. Based on these four data matrices, four tree topologies were recovered. Relationships among non-leptosuchomorph phytosaurs are largely consistent between these four topologies, whereas those of more derived taxa are more variable. Rutiodon carolinensis consistently forms a sister relationship with Angistorhinus. In three topologies Nicrosaurus nests deeply within a group of traditionally Submitted 24 April 2018 non-Mystriosuchini taxa, leading us to redefine Mystriosuchini by excluding 9 October 2018 Accepted Nicrosaurus as an internal specifier. Two distinct patterns of relationships within Published 10 December 2018 Mystriosuchini are present in the four topologies, distinguished largely by the Corresponding author Andrew S.
  • A Large Predatory Archosaur from the Late Triassic of Poland

    A Large Predatory Archosaur from the Late Triassic of Poland

    A large predatory archosaur from the Late Triassic of Poland GRZEGORZ NIEDŹWIEDZKI, TOMASZ SULEJ, and JERZY DZIK Niedźwiedzki, G., Sulej, T., and Dzik, J. 2012. A large predatory archosaur from the Late Triassic of Poland. Acta Palaeontologica Polonica 57 (2): 267–276. We describe a new large predatory archosaur, Smok wawelski gen. et sp. nov., from the latest Triassic (latest Norian–early Rhaetian; approximately 205–200 Ma) of Lisowice (Lipie Śląskie clay−pit) in southern Poland. The length of the recon− structed skeleton is 5–6 m and that of the skull 50–60 cm, making S. wawelski larger than any other known predatory archosaur from the Late Triassic and Early Jurassic of central Europe (including theropod dinosaurs and “rauisuchian” crurotarsans). The holotype braincase is associated with skull, pelvic and isolated limb−bones found in close proximity (within 30 m), and we regard them as belonging to the same individual. Large, apparently tridactyl tracks that occur in the same rock unit may have been left by animals of the same species. The highly autapomorphic braincase shows large at− tachment areas for hypertrophied protractor pterygoideus muscles on the lateral surface and a wide, funnel−like region be− tween the basal tubera and basipterygoid processes on the ventral surface. The skeleton (cranial and postcranial) pos− sesses some features similar to those in theropod dinosaurs and others to those in large crocodile−line archosaurs (“rauisuchians”), rendering phylogenetic placement of S. wawelski difficult at this time. Key words: Archosauria, “Rauisuchia”, Dinosauria, Norian–Rhaetian, Late Triassic, Poland. Grzegorz Niedźwiedzki [[email protected]], Institute of Zoology, University of Warsaw, ul.
  • Vertebrate Fauna of the Dockum Group, Triassic, Eastern New Mexico and West Texas Joseph P

    Vertebrate Fauna of the Dockum Group, Triassic, Eastern New Mexico and West Texas Joseph P

    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/23 Vertebrate fauna of the Dockum Group, Triassic, eastern New Mexico and West Texas Joseph P. Gregory, 1972, pp. 120-123 in: East-Central New Mexico, Kelley, V. C.; Trauger, F. D.; [eds.], New Mexico Geological Society 23rd Annual Fall Field Conference Guidebook, 236 p. This is one of many related papers that were included in the 1972 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.