Eubrachythoracid arthrodires with tubular rostral plates from Gogo, Western Australia

Two monotypic genera of tubular-snouted eubrachythoracid arthrodires are described from the Upper Devonian Gogo Formation of Western Australia as Rolfosteur gen nov. and Tubonnsus gen. nov. They are most closely related to Camuropiscis Dennis & Miles, also from the Gogo Formation, and all three are therefore placed in the family Camuropiscidae nov. Rolfosteus and Tubonasus are jointly the sister-group of Camuropiscis .     

A primitive eubrachythoracid arthrodire from Gogo, Western Australia

A new eubrachythoracid arthrodire, Hanytoombsia elegans gen. et sp. nov., is described from the Upper Devonian Gogo formation of Western Australia. Its structure and relationships are discussed within the framework provided by a new sketch cladogram for arthrodires. H. elegans is morphologically similar to Coccosteus cuspidatus , but its relationships among primitive eubrachythoracids are unknown.     

A pachyosteomorph arthrodire from Gogo, Western Australia

A new monotypic genus of eubrachythoracid arthrodire is described from die Upper Devonian Gogo Formation of Western Australia as Incisoscutum ritchiei gen. et sp. nov. It is at die pachyosteomorph level of organization, having no contact between the plates of die flank and those of the ventral shield behind the pectoral fin. It is interchangeable widi Coccosteus spp. and a number of earlier described Gogo forms in a sketch dadogram for arthrodires, but its phylogenedc relationships are unknown. Well preserved material of die scapulocoracoid throws new light on die structure of this element in arthrodires, particularly widi respect to variations in die pattern of canals and foramina.     

A second eubrachythoracid arthrodire from Gogo, Western Australia

A new genus of long-snouted, eubrachythoracid arthrodire, Camuropiscis gen. nov., is described from the Upper Devonian Gogo formation of Western Australia. It is represented by two species, the type C. concinnus sp. nov. and C. laidlawi sp. nov. These species are interchangeable with Coccosteus spp. in a sketch cladograin for arthrodires; their phylogenetic relationships are not known in any detail. C. concinnus has a well-preserved pelvic girdle and throws new light on the structure of this element in arthrodires.     

A eubrachythoracid arthrodire with a snubnose from Gogo, Western Australia

A new eubrachythoracid arthrodire, Simosteus tuberculatus gen. et sp. nov., is described from the Upper Devonian Gogo Formation of Western Australia and its structure and relationships are discussed. It is related to the trematosteids, leiosteids and hadrosteids on the evidence of 'fused' preorbital and postnasal bones.     

Eubrachythoracid arthrodires from Gogo, Western Australia

Two monotypic genera of coccosteoid eubrachythoracid arthrodires are described from the Upper Devonian Gogo Formation of Western Australia as Compagopiscis gen. nov. and Gogopiscis gen. nov. They are most closely related to Torosteus Gardiner & Miles, also from the Gogo Formation, and all three are placed in the family Plourdosteidae Vezina, 1990; Compagopiscis and Gogopiscis are jointly the sister-group of Torosteus.     

A new camuropiscid arthrodire (Pisces: Placodermi) from Gogo, Western Australia

A new camuropiscid arthrodire, Latocamurus coulthardi gen. et sp. nov., is described from the Upper Devonian Gogo Formation, Western Australia. Latocamurus , known from two complete specimens, is recognized as a camuropiscid by its narrow, spindle-shaped armour, deep postnasal plates participating in the orbits, preorbital plates which meet mesially, cheek unit firmly sutured to skull roof, posterior check plates tightly interconnected and much reduced, and the robust durophagous dentition. It is characterized by its downturned snout, broad, flat rostral plate, and narrow, deep parasphenoid. It is placed phyletically as the plesiomorphic sister taxon to all other camuropiscids which are more derived in having, inter alia , an anterior lateral plate which anteriorly contacts the anterior ventrolateral plate and pointed rostral plates. The family Camuropiscidae Dennis & Miles 1979b is redefined to incorporate features of the new genus. Camuropiscids and Incisoscutum are closely related by features of the postnasal plate and cheek.     

A new species of eastmanosteid arthrodire (Pisces: Placodermi) from Gogo, Western Australia

A new species of Eastmanosteus Obruchev is described from the Upper Devonian Gogo Formation of Western Australia as E. calliaspis sp. nov. It is at the pachyosteomorph level of organization having no contact between the plates of the flank and those of the ventral shield behind the pectoral fin. Well preserved material of the parasphenoid and scapulocoracoid throws further light on the structure of these elements in arthrodires. The genus Eastmanosteus is reviewed.     

New ischnacanthid acanthodians from the Early Devonian of Australia, with comments on acanthodian interrelationships

Rockycampacanthus milesi n.gen., n.sp. is described from a single jaw from the Rocky Camp member of Lower Devonian Buchan Group, E Victoria. Rockycampacanthus differs from other ischnacanthiforms in having large multicuspidate teeth with dual rows of secondary cusps forming a posteromesial flange, a mesial tooth row beginning opposite the fourth cusp of the main tooth row, and in the gnathal bone being deepest in the anterior half. Taemasacanthus erroli n. gen., n. sp. is described from several jaw bones from the Lower Devonian Murrumbidgee Group, New South Wales. Taemasacanthus has a well developed posterolabial flange with secondary cusps developed, vertical rows of denticles on the cusps of the main tooth row and a well developed mesial tooth row separated from the main row by a prominent ridge. The labial face of the jaw has a circular ridge which may have supported labial cartilages. The complex mandibular joint in climatiforms, acanthodiiforms and some primitive sharks differs from the simple jaw articulation of ischnacanthids. It is suggested that ischnacanthids are the plesiomorphic sister group to climatiforms plus acanthodiiforms. The interrelationships of ischnacanthids, climatiforms and acanthodiforms are discussed.     

A New Eurypterid (Chelicerata: Eurypterida) from the Upper Devonian Gogo Formation of Western Australia, With A Review of the Rhenopteridae

A new eurypterid, Rhenopterus waterstoni sp. nov., is described from the Gogo Formation (Frasnian, Upper Devonian) of Western Australia. This species is distinguished from related forms by the tuberculation of the anteriormost tergite and crenulated posterior margins of the carapace and opisthosomal segments. It is the only eurypterid specimen known from the Gogo Formation, the most complete eurypterid from Australia, and also the youngest representative of Rhenopterus in the fossil record. Structures retrieved from between the prosomal-opisthosomal juncture comprise polygonal tubes 30–40 μm in diameter, which are interpreted as sarcomeral sheaths of muscular tissue. Rhenopterus is reviewed: R. latus Størmer, 1936 is synonymized with R. diensti Størmer, 1936 as it is here recognized as a female sexual dimorph; R. maccarthyi (Kjellesvig-Waering, 1934) is an orthocone nautiloid.     

Siluro-devonian Conodonts from the Camelford Limestone, Wellington, New South Wales, Australia

Conodont data have been utilized to identify the Silurian/Devonian boundary within the Camelford Limestone near Wellington, NSW. Conodont faunas are documented from the eosteinhornensis Zone to early delta Zone with one new species of Walliserodus ( W. multistriatus ) and two new species of Ozarkodina ( O. brocki and O. camelfordensis ) described. An apparatus reconstruction of Belodella anomalis is also presented.     

Reanalysis of Heintzichthys gouldii (Newberry), an aspinothoracid arthrodire (Placodermi) from the Famennian of northern Ohio, with a review of brachythoracid systematics

Heintzichthys gouldii is redescribed based on new material from the Interstate 71 Paleontological Salvage Project (Cleveland Museum of Natural History, 1966-67). Phylogenetic analysis of brachythoracid arthrodires clearly shows the monophyly of Camuropiscidae and the aspinothoracid arthrodires. Heintzichthys gouldii and Gorgonichthys clarki are removed from Dinichthyidae and placed within aspinothoracid arthrodires. The remaining members in the family Dinichthyidae are united solely by plesiomorphic characters. A number of putative synapomorphies for the eubrachythoracid arthrodires are questioned; however, the validity of this taxon is supported by three synapomorphies.     

A new actinolepid arthrodire (Class Placodermi) from the Lower Devonian Sevy Dolomite, East-Central Nevada

A new genus and species of actinolepid arthrodire, Aleosteus eganensis , is described from the Lower Devonian (Late Emsian) Sevy Dolomite in the Egan Range of east-central Nevada. A cladistic analysis of the family Actinolepidae is presented for the first time and shows the Baltic Actinolepis species form the primitive sister-group of all other actinolepids. Rapid evolution of the Actinolepidae during the Lochkovian is reflected in the dispersal of the family around the Old Red Sandstone Continent at this time followed by the development of endemic faunas through the Lower Devonian and into the Middle Devonian.     

Patterns of evolution and extinction in proetid trilobites during the late Devonian mass extinction event,Canning Basin,Western Australia

Abstract: In the early Late Devonian, terminal Frasnian proetid trilobites have previously only been known from Europe and North Africa. For the first time, a rich fauna of late Frasnian proetids is described from the Virgin Hills Formation, Canning Basin, Western Australia. Seventeen species in six genera are described, of which three are new: Rudybole gen. nov., Palpebralina gen. nov. and Canningbole gen. nov. A new subgenus, Chlupaciparia (Australoparia) subgen. nov. is also described. Fourteen of the species are new: Palpebralia initialis sp. nov., P. pustulata sp. nov., ?P. sp. nov. A, Rudybole depressa sp. nov., Palpebralina pseudopalpebralis sp. nov. (comprising the subspecies P. pseudopalpebralis pseudopalpebralis subsp. nov. and P. pseudopalpebralis ultima subsp. nov.), P. minor sp. nov., P. ocellifer sp. nov., Canningbole latimargo sp. nov., C. henwoodorum sp. nov., C. macromma sp. nov., Pteroparia extrema sp. nov., Chlupaciparia (Chlupaciparia) planiops sp. nov., Chlupaciparia (Australoparia) australis sp. nov. and C. (Australoparia) lata sp. nov. The subspecies Rudybole adorfensis angusta subsp. nov. is also described. The proetids range through conodont Zones 11–13b and terminate at the Upper Kellwasser Event, which marks the terminal Frasnian mass extinction event. Three of the six proetid lineages, Palpebralia, Canningbole and Pteroparia, show evolutionary trends of eye reduction. Two of the remaining lineages, Rudybole and Palpebralina, consist exclusively of blind taxa. The last, Chlupaciparia, also comprises forms with reduced eyes. The proetids show a stepped pattern of extinction during the late Frasnian, which correlate with two Kellwasser biocrises documented in European/North African Frasnian sections. The highest diversity preceded the Lower Kellwasser event that occurred at the end of conodont Zone 12 and saw the extinction of all species present in that zone. However, only one genus, Pteroparia, locally became extinct. A major higher‐level taxonomic mass extinction at the top of Zone 13b initiated the Upper Kellwasser extinction event. This included extinction at the generic level, with all five remaining genera becoming extinct, and at the family level, with the loss of the Tropidocoryphidae.     

Biogeographic history of subterranean isopods from groundwater calcrete islands in Western Australia

Groundwater calcretes in arid central Western Australia contain a diverse invertebrate groundwater fauna (stygofauna). Surveys have uncovered a diverse oniscidean isopod subterranean fauna above the water table (troglofauna), including species of a recently described genus Paraplatyarthrus. The aim of this study was to investigate the biogeographic history of Paraplatyarthrus and the timing of transitions from surface to subterranean habitats. Phylogenetic relationships among the isopod troglofauna from 11 groundwater calcretes along three palaeodrainage systems were assessed using one mitochondrial gene, cytochrome c oxidase subunit 1 (COI), and two nuclear markers, lysyl‐tRNA synthetase (LysRS) and 18S rRNA (18S) genes. Phylogenetic analyses revealed multiple sister lineage relationships between troglophile and troglobite lineages and evidence for divergent mtDNA lineages within species, providing a range of nodes for dating evolutionary transitions from surface to subterranean habitats. Relaxed molecular clock analyses provided evidence that evolutionary transitions from surface to subterranean environments took place between 13.3 and 1.75 million years ago, coinciding with the onset of aridification of Australia from the late Tertiary. In cases where groundwater calcretes contained multiple species, the taxa were not closely related phylogenetically, suggesting that these calcretes were independently colonised by multiple ancestral species. The study further confirmed the role of late/post‐Miocene aridification as a key driver of the evolution of subterranean invertebrates in the calcrete islands of Western Australia, supporting the climatic relict hypothesis. Troglobites most likely evolved from the troglophile ancestors that were capable of dispersal among, and active colonisation of, calcretes.     

Rhagada revisited: on the taxonomy of species from the Kimberley and Dampierland,Western Australia (Pulmonata,Camaenidae)

The genus Rhagada is the second most diverse camaenid genus in Australia. We examined anatomical and mitochondrial characters of previously unidentified material from the Kimberley that was earmarked to potentially represent new species in recently published molecular phylogenetic studies. Our comparisons revealed that specimens from Gibbings Island (‘R. sp. Gibbings’) were morphologically and genetically most similar to Rhagada cygna from the Dampier Peninsula. Hence, ‘R. sp. Gibbings’ is considered to be identical to R. cygna. In addition, we found that R. cygna as so delimited is not clearly distinguished from the second species on the Dampier Peninsula, Rhagada bulgana. Both species differ rather subtly in anatomical and mitochondrial characters, indicating their close relationships and potentially incomplete evolutionary differentiation. Furthermore, we describe two new species based on comparative morphology and mitochondrial sequences: Rhagada worora n. sp. from the Prince Regent Reserve in the Kimberley and Rhagada karajarri n. sp. from Dampierland. The present study confirms that species in Rhagada are best identified by means of both morphological and molecular data.

http://zoobank.org/urn:lsid:zoobank.org:pub:556E1866-6F9E-4CC0-8ACF-CD56E929501F     

广西下泥盆统南极鱼类(盾皮鱼纲:节甲鱼目)一新属(英文)

依据采自广西平果早泥盆世郁江组中部的化石材料,记述了盾皮鱼纲节甲鱼目南极鱼科的一新属、新种——小眼坡塘鱼(Potangaspis parvoculatusgen.et sp.nov.)。该新属的眶孔很小,且为颅顶甲骨片所完全包围;中点线沟发育,与眶上感觉沟、中心感觉沟和后点线沟一起共同向颈片的骨化中心辏合。系统发育分析表明新属和发现于南极洲中泥盆统的南极鱼属构成姐妹群关系,支持了南极鱼科位于节甲鱼目最基干位置的假说,同时为早埃姆斯期东冈瓦纳大陆与中国南方之间的古地理密切联系提供了新的证据。