Arceoaster hintei n. gen. n. sp., a late Silurian homeomorphic asteroid (Echinodermata, Hudsonasteridae)

2020 ◽  
Vol 95 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Daniel B. Blake ◽  
James Sprinkle
Keyword(s):  
New Genus ◽  
Life Strategy ◽  
Time Interval ◽  
Invertebrate Fauna ◽  
Crown Group ◽  
Selective Pressures ◽  
Early Mesozoic ◽  
Environmental Setting ◽  
Southern Oklahoma ◽  
Iterative Evolution

AbstractThe late Silurian Arceoaster hintei new genus new species (Asteroidea, Echinodermata) is based on a single complete specimen from the lower Hunton Group of southern Oklahoma. Overall ossicular arrangement enables assignment of the new genus to the Paleozoic stem-family Hudsonasteridae; however, Arceoaster n. gen. is homeomorphic with members of the post-Paleozoic crown-group Goniasteridae. Because Arceoaster n. gen. is a hudsonasterid, and because similar morphologic expressions are not known among described taxa from later in the Paleozoic or the early Mesozoic, similarities between Arceoaster n. gen. and later genera are homoplastic, thereby providing an example of iterative evolution within Asteroidea. The Arceoaster n. gen. specimen is associated with a rich and diverse invertebrate fauna typical of its time interval and environmental setting; nothing suggests an unusual habitat. Selective pressures leading to homoplasy are conjectural, although robust construction among extant asteroids has been associated with a defensive life strategy.UUID: http://zoobank.org/b1d8461d-7e54-43cc-8719-97304ca3fd7a

scholarly journals Two new genera of Cretaceous dustywings in amber from northern Myanmar (Neuroptera: Coniopterygidae)

2016 ◽  
pp. 1 ◽  
Author(s):  
Michael S. Engel
Keyword(s):  
Upper Cretaceous ◽  
New Genus ◽  
New Genera ◽  
New Genus And Species ◽  
Crown Group ◽  
Labial Palpus ◽  
Head Form

Two new genera and species are added to the fauna of dustywings (Coniopterygidae) preserved in Upper Cretaceous (earliest Cenomanian) amber of northern Myanmar, doubling the described diversity from this deposit.  One genus is of the subfamily Aleuropteryginae and described as Achlyoconis heptatrichia Engel, new genus and species.  This species is noteworthy for the infumate and patterned wings and unique presence of seven prominent setae positioned on thickenings occurring along the length of the forewing media.  Paranimboa litotes Engel, new genus and species, is representative of the subfamily Coniopteryginae and distinctive among Mesozoic groups for the unbranched Rs, among other traits.  In addition, a peculiar larva preserved alongside the holotype of P. litotes is described.  While having a prothoracic and head form similar to aleuropterygines as well as a labial palpus with only two palpomeres, diagnostic for Coniopterygidae, the antenna bears four articles rather than the two present in crown-group dustywings.  A revised key to the genera of Cretaceous Coniopterygidae is provided.

The complex morphology of a new Lower Silurian asteroid (Echinodermata)

2009 ◽  
Vol 83 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Daniel B. Blake ◽  
Frank R. Ettensohn
Keyword(s):  
New Genus ◽  
New Genus And Species ◽  
Crown Group ◽  
East Central ◽  
Lower Silurian ◽  
Complex Morphology

Gordonaster brassfieldensis is a new genus and species of Asteroidea (Echinodermata) described from the Lower Silurian Brassfield Formation of east-central Kentucky. Tentatively assigned to the poorly understood Palaeasteridae, Gordonaster shares much with Ordovician asteroids, yet it also exhibits apparent homoplasies that presage the post-Paleozoic crown group. Available specimens also indicate that the ontogenetic pattern of ossicular addition seen in the crown group was established during the Paleozoic.

The Sweetognathus complex in the Permian of China: implications for evolution and homeomorphy

1987 ◽  
Vol 61 (5) ◽  
pp. 1047-1057 ◽  
Author(s):  
Wang Cheng-Yuan ◽  
Scott M. Ritter ◽  
David L. Clark
Keyword(s):  
New Species ◽  
North America ◽  
New Genus ◽  
Late Permian ◽  
Western North America ◽  
Evolutionary Studies ◽  
Complete Sequences ◽  
Iterative Evolution

The well-exposed and fossiliferous Permian carbonates in China have yielded Early and Late Permian species of the Sweetognathus complex that permit worldwide stratigraphic evaluation of members of the group. The sporadic appearance of species of Sweetognathus and related genera throughout the Permian in western North America and Iran, in particular, may represent iterative evolution and homeomorphy. The pectiniform element morphologies of the several species are interpreted as most important for evolutionary studies and document a partial Permian biostratigraphy in China that aids in the interpretation of less complete sequences elsewhere. A new genus, Pseudosweetognathus, and four new species, Pseudosweetognathus costatus, Sweetognathus subsymmetricus, S. paraguizhouensis, and Iranognathus nudus, are described.

An asteroid (Echinodermata) faunule from the Oxfordian Swift Formation (Upper Jurassic) of Montana

2016 ◽  
Vol 90 (6) ◽  
pp. 1160-1168
Author(s):  
Daniel B. Blake ◽  
Thomas E. Guensburg
Keyword(s):  
New Genus ◽  
Upper Jurassic ◽  
Wide Distribution ◽  
Time Interval ◽  
New Genus And Species ◽  
The North ◽  
Class Level ◽  
Regional Location ◽  
Favorable Conditions ◽  
Continental Interior

AbstractA new Late Jurassic (Oxfordian) asteroid (Echinodermata) faunule from the Swift Formation of Montana includes representatives of four genera including the new genus and speciesAtalopegaster gundersoni(Stichasteridae),Eokainastersp. indet. (Astropectinidae), an indeterminate probable member of the Goniasteridae, and a species indeterminate beyond the class level. Because of weathering at the outcrop, preservation is poor.Although representing an unusual depositional occurrence, overall faunule composition appears comparable to that found in a similar modern environment. The faunule is comparable in age and regional location to earlier Jurassic asteroid discoveries, suggesting wide distribution during a geologically brief time interval of favorable conditions. Asteroids are only rarely reported from the Mesozoic of the North American continental interior, and co-occurrence of multiple fossil taxa is unusual on a global basis.

scholarly journals A new genus of horse from Pleistocene North America

2017 ◽  
Author(s):  
Peter D. Heintzman ◽  
Grant D. Zazula ◽  
Ross D.E. MacPhee ◽  
Eric Scott ◽  
James A. Cahill ◽  
...  
Keyword(s):  
North America ◽  
New World ◽  
New Genus ◽  
Single Species ◽  
Geographic Range ◽  
Crown Group ◽  
Limb Bones ◽  
Morphometric Analyses ◽  
Extinction Event ◽  
Terminal Pleistocene

AbstractThe extinct “New World stilt-legged”, or NWSL, equids constitute a perplexing group of Pleistocene horses endemic to North America. Their slender distal limb bones resemble those of Asiatic asses, such as the Persian onager. Previous palaeogenetic studies, however, have suggested a closer relationship to caballine horses than to Asiatic asses. Here, we report complete mitochondrial and partial nuclear genomes from NWSL equids from across their geographic range. Although multiple NWSL equid species have been named, our palaeogenomic and morphometric analyses support the idea that there was only a single species of middle to late Pleistocene NWSL equid, and demonstrate that it falls outside of crown group Equus. We therefore propose a new genus, Haringtonhippus, for the sole species H. francisci. Our combined genomic and phenomic approach to resolving the systematics of extinct megafauna will allow for an improved understanding of the full extent of the terminal Pleistocene extinction event.

Homeomorphy in the Asteroidea (Echinodermata); a new Late Cretaceous genus and species from Colorado

2002 ◽  
Vol 76 (6) ◽  
pp. 1007-1013 ◽  
Author(s):  
Daniel B. Blake ◽  
Barry S. Kues
Keyword(s):  
Upper Cretaceous ◽  
New Genus ◽  
New Genus And Species ◽  
Limited Evidence ◽  
Morphological Response ◽  
Shallow Marine ◽  
Body Form ◽  
Selective Pressures ◽  
Modern Species ◽  
The Family

Codellaster keepersae new genus and species, from the Upper Cretaceous Codell Sandstone Member of the Carlile Shale of Colorado (U.S.A.), is assigned to the asteroid (Echinodermata) family Goniasteridae. Although clearly a goniasterid, the flattened body form and details of morphology of C. keepersae are remarkably similar to corresponding features of the modern astropectinid Astropecten regalis and also of the luidiid Luidia (Platasterias) latiradiata. The discovery facies of C. keepersae includes low-angle crossbeds and asymmetrical ripple marks that are suggestive of a very shallow marine environment. Both the modern species occur in shallow, turbulent settings, and homeomorphy beween ancient and modern asteroids suggests similar selective pressures and evolutionary responses. Limited evidence suggests goniasterids might have been more common in shallower waters during the Cretaceous than they are today, and absence of modern Codellaster-like goniasterids indicates that the family abandoned these habitats, although the fundamental morphological response to such settings remained viable for asteroid organization.

The Triassic isopod Protamphisopus wianamattensis (Chilton) and comparison by extant taxa (Crustacea, Phreatoicidea)

2003 ◽  
Vol 77 (3) ◽  
pp. 454-470
Author(s):  
George D. F. Wilson ◽  
Gregory D. Edgecombe
Keyword(s):  
Middle Triassic ◽  
Cladistic Analysis ◽  
Late Paleozoic ◽  
Late Permian ◽  
Habitat Shift ◽  
Crown Group ◽  
Early Mesozoic ◽  
The Family ◽  
Minimum Age ◽  
Character Set

Protamphisopus wianamattensis (Chilton, 1918) from the Middle Triassic (Anisian) Ashfield Shale in the Sydney Basin, Australia, is the earliest-known freshwater representative of the basal isopod suborder Phreatoicidea. In contrast, the late Paleozoic Palaeophreatoicidae species, which are morphologically distinct from extant families, are found in marine or estuarine facies. Comparison of Protamphisopus wianamattensis with living Phreatoicidea permits the external morphology of the fossils to be reconstructed and the species to be coded for cladistic analysis using a revised and expanded character set developed for living phreatoicideans. In resulting parsimonious trees as well as immediately suboptimal trees, Protamphisopus is nested within clades related to the family Amphisopodidae. Although not included in the analysis, the Late Permian Protamphisopus reichelti Malzahn (in Glaessner and Malzahn, 1962) appears to be a member of the Palaeophreatoicidae, rather than among the crown group of the Phreatoicidea. Therefore, a minimum age of Middle Triassic can be assigned to the basal branches within the phreatoicid crown group. The minimum age for the colonisation of fresh water by the suborder is also established although, given the advanced position of Protamphisopus wianamattensis in the cladograms, the habitat shift may have occurred earlier. The biogeographic distribution of extant Phreatoicidea on fragments of Gondwana is consistent with early Mesozoic origins for the major clades of this isopod suborder.

The first fossil horntail wasp (Hymenoptera: Siricidae) from Lower Cretaceous Crato Formation in Brazil

2020 ◽  
Vol 3 (4) ◽  
pp. 382-389
Author(s):  
CORENTIN JOUAULT ◽  
JEAN-MARC POUILLON ◽  
ANDRÉ NEL
Keyword(s):  
Lower Cretaceous ◽  
New Genus ◽  
Sister Group ◽  
The Other ◽  
Northeastern Brazil ◽  
Crown Group ◽  
The Family ◽  
Group Relationships ◽  
Fossil Records ◽  
New Discovery

A new wood wasp, Cratosirex sennlaubi gen. et sp. nov., is described and figured from one specimen collected from the Lower Cretaceous Crato Formation in northeastern Brazil. This new genus is placed in the new siricid subfamily Cratosiricinae subfam. nov., based on a combination of plesiomorphic and autapomorphic characters. The presence of small and sub-equal forewing cells 1R1 and 2R1 is a synapomorphy with the extant subfamily Siricinae, absent in the other extinct subfamilies †Auliscinae and †Gigasiricinae, supporting a sister group relationships with the Siricinae. Our new discovery expands the distribution range of Siricidae fossil records, highlights the antiquity of the family, and emphasizes the need for more studies of this particular insect lineage in the Mesozoic deposits. Currently, all the representatives of the crown group of the extant Siricidae are Cenozoic.

Ossicular homologies, systematics, and phylogenetic implications of certain North American Carboniferous asteroids (Echinodermata)

2003 ◽  
Vol 77 (3) ◽  
pp. 476-489 ◽  
Author(s):  
Daniel B. Blake ◽  
Dan R. Elliott
Keyword(s):  
Body Wall ◽  
New Genus ◽  
Prey Type ◽  
The Body ◽  
Late Paleozoic ◽  
Crown Group ◽  
Phylogenetic Implications ◽  
Phylogenetic Resolution ◽  
Defensive Mechanism

Emphereaster missouriensis new genus and species, Ambigaster, new genus, and Delicaster, new genus are assigned to the Carboniferous asteroid family Neopalaeasteridae Schuchert. The neopalaeasterids are similar to but separable from the Carboniferous Monasteridae, Calliasterellidae, and Fandasteridae, n. fam., in ambulacral and other characters. The several families indicate that late Paleozoic asteroids were diverse although poorly documented.Similarities between late Paleozoic stem-group and post-Paleozoic crown-group asteroids allow argumentation on ossicular homologies. In species with only a single row of arm marginals, an earlier suggestion that certain disk ossicles are superomarginals is rejected. Enlarged proximal adambulacrals fill space on the actinal surface whereas actinal ossicles, generally lacking in Paleozoic asteroids, provide the space-filling service in crown-group asteroids.The body wall beyond the ambulacral column and accessory ossicles traditionally have been stressed in the classification of asteroids of all ages. Because of body wall homoplasies, many older taxonomic concepts do not identify monophyletic late Paleozoic clades, nor do they indicate the derivation of the crown group. Ambulacral characters in contrast are conservative through long periods of geologic time, improving phylogenetic resolution as more taxonomic data become available. Now-available ambulacral skeletal data for certain Carboniferous genera suggest membership in lineages basal to the post-Paleozoic crown group.Emphereaster missouriensis and most neopalaeasterids are stoutly constructed suggesting a defensive mechanism against durophagous chondrichthyan fish that co-occur with the holotype of Emphereaster. Abundant sponge spicules within the disk of the holotype suggest it fed on sponges, a prey type widely exploited by living asteroids.

New sea turtle from the Miocene of Peru and the iterative evolution of feeding ecomorphologies since the Cretaceous

2010 ◽  
Vol 84 (2) ◽  
pp. 231-247 ◽  
Author(s):  
James F. Parham ◽  
Nicholas D. Pyenson
Keyword(s):  
Middle Miocene ◽  
New Genus ◽  
Ecological Factors ◽  
Sea Turtle ◽  
New Taxon ◽  
Feeding Apparatus ◽  
New Genus And Species ◽  
Additional Information ◽  
Iterative Evolution ◽  
Osteological Characters

The seven species of extant sea turtles show a diversity of diets and feeding specializations. Some of these species represent distinctive ecomorphs that can be recognized by osteological characters and therefore can be identified in fossil taxa. Specifically, modifications to the feeding apparatus for shearing or crushing (durophagy) are easily recognizable in the cranium and jaw. New sea turtle fossils from the Miocene of Peru, described as a new genus and species (Pacifichelys urbinain. gen. and n. sp.), correspond to the durophagous ecomorph. This new taxon is closely related to a recently described sea turtle from the middle Miocene of California, USA (Pacifichelys hutchisonin. comb.), providing additional information on the osteological characters of this lineage. A phylogenetic analysis ofPacifichelysand other pan-chelonioid sea turtle lineages shows that at least seven lineages independently evolved feeding specialized for shearing or crushing. the iterative evolution of these morphologies is plausibly linked to ecological factors such as the development of seagrass communities and the opening of niches through extinction that occurred from the Cretaceous to the Miocene.

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