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Re: [dinosaur] New Lariosaurus species from Middle Triassic of Germany + new Ichthyosaurus conybeari specimen



Ben Creisler <bcreisler <at> gmail.com> writes:

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> Ben Creisler
> bcreisler <at> gmail.com
> 
> Two new marine reptiles papers in the JVP:
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> Lariosaurus  vosseveldensis
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> Nicole Klein, Dennis F. A. E. Voeten, Adam Haarhuis & Remco Bleeker (2016)
> The earliest record of the genus Lariosaurus from the early middle 
Anisian (Middle Triassic) of the Germanic Basin. 
> Journal of Vertebrate Paleontology (advance online publication) 
> DOI: 10.1080/02724634.2016.1163712
> http: // www.tandfonline.com/doi/full/10.1080/02724634.2016.1163712
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> A new skull representing the oldest record of the genus Lariosaurus in 
the Germanic Basin is described. The small-sized skull originates from the 
early middle Anisian (Bithynian) of the Winterswijkse Steengroeve 
(Winterswijk, The Netherlands) and is assigned to L. vosseveldensis, sp. 
nov. Supplementation of a recently established phylogeny with L. 
vosseveldensis, sp. nov., recovered it within Lariosaurus as the sister 
taxon to Nothosaurus winkelhorsti and L. buzzii. The generic assignment of 
N. juvenilis, N. youngi, and N. winkelhorsti to Nothosaurus must be 
reevaluated to reestablish support for a monophyletic Lariosaurus, and only 
a definitive resolution of the polytomy including Germanosaurus could 
recover a monophyletic Nothosauridae. The Winterswijk locality has 
previously yielded a rich and diverse marine reptile fauna, including an 
endemic basal placodont. The nearly contemporaneous occurrence of L. 
vosseveldensis, sp. nov., and L. hongguoensis from the middle Anisian 
(Pelsonian) of China indicates a very rapid dispersal of the group, but 
does not resolve the origin of Sauropterygia (eastern Tethyan faunal 
province vs. western Tethyan faunal province).
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> https://urldefense.proofpoint.com/v2/url?u=http-3A__zoobank.org_urn-3Alsid-3Azoobank.org-3Apub-3A9FAFC2A0-2D77CE-2D476F-2D938A-2D&d=DQIGaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=X-u8Bk241RWFCkJZN-fDivAvfqK3mx3OxB2Z8l-unx8&s=AMXzJQoD2D-5AKIRKT8h3XX9M0fjYENGE57EwnHtEn8&e=
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7858EDA61FBA
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> ==
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> Judy A. Massare & Dean R. Lomax (2016)
> A new specimen of Ichthyosaurus conybeari (Reptilia, Ichthyosauria) from 
Watchet, Somerset, England, U.K., and a reexamination of the species. 
> Journal of Vertebrate Paleontology (advance online publication) 
> DOI: 10.1080/02724634.2016.1163264.
> http: // www.tandfonline.com/doi/full/10.1080/02724634.2016.1163264
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> Ichthyosaurus conybeari is a rare species, previously known only from an 
incomplete holotype and one referred specimen, both from the Lyme Regis 
area of the west Dorset coast, U. K. A newly recognized, nearly complete 
specimen (NMW 93.5G.2) is the first occurrence of the species in Somerset, 
U. K. A revised diagnosis recognizes new morphological characters that 
distinguish the species: slender maxilla with a long, delicate premaxillary 
process; narrow postorbital; humerus with an anteriorly offset dorsal 
process that has a well-defined lip extending slightly into the shaft; 
fibula that is much larger dorsoventrally and mediodistally than tibia; and 
wide rectangular ischium that is much shorter than the pubis and femur. 
Notching of anterior fin elements in the forefin had been used as a 
diagnostic character, but a review of notching within Ichthyosaurus 
suggests that it has little taxonomic utility. Another specimen (NHMUK 
R15907), herein referred to the species, extends the range of I. conybeari 
from the upper Hettangian to lower Pliensbachian stages of the Lower 
Jurassic, the longest duration of any species of the genus.
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> SUPPLEMENTAL DATA—Supplemental materials are available for this article 
for free at www.tandfonline.com/UJVP
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Having looked at the full contents of the paper, including the cladistic 
analysis, I've noticed that Nothosaurus is paraphyletic with respect to 
Lariosauus, because it would necessitate removal of Conchiosaurus from 
synonymy with Nothosaurus (potentially necessitating a petition to have to 
ICZN reinstate Conchiosaurus), since Rieppel (1996) synonymized 
Conchiosaurus clavatus with Nothiosaurus marchius and N. marchius falls in 
the Klein et al. cladogram as closer to Lariosaurus than to the Nothosaurus 
type species N. mirabilis.