New taxa: Spitrasaurus, Djupedalia, Pliosaurus funkei (Plesiosauria); Cryopterygius, Palvennia (Ichthyosauria) [free pdfs!]

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


The new issue of the Norwegian Journal of Geology contains a wealth of
papers about the marine reptiles discovered on Spitsbergen in the
Svalbard archipelago region of Norway. All the papers are open access
and can be downloaded in two forms (lower resolution for computer use
and higher quality for printing).
Many thanks to Jørn Hurum for notifying me of the new issue!

http://www.geologi.no/cgi-bin/geologi/imaker?id=6862&visdybde=1&aktiv=6862

===

Jørn H. Hurum, Hans A. Nakrem, Øyvind Hammer, Espen M. Knutsen,
Patrick S. Druckenmiller, Krzysztof Hryniewicz & Linn K. Novis (2012)
An Arctic Lagerstätte – the Slottsmøya Member of the Agardhfjellet
Formation (Upper Jurassic – Lower Cretaceous) of Spitsbergen.
Norwegian Journal of Geology 92 (2-3): 55-64
ISSN 029-196X.
low: http://www.geologi.no/data/f/0/21/07/3_2401_0/NJG_2_3_2012_1_Hurum_Scr.pdf
high: http://www.geologi.no/data/f/0/21/07/4_2401_0/NJG_2_3_2012_1_Hurum_Pr.pdf

Paleontological fieldwork on Spitsbergen, 2004-2011, has revealed the
presence of abundant plesiosaur and ichthyosaur remains, a series of
15 seep carbonate bodies, as well as a rich invertebrate fauna from
the Upper Jurassic – Lower Cretaceous Slottsmøya Member of the
Agardhfjellet Formation, a 70-100 metre-thick unit of dark grey to
black shale and paper shale. Deposition of the Slottsmøya Member
occurred at high paleolatitudes, at or near the Arctic Circle, and
molluscan and foraminiferal biostratigraphy indicates an Early Volgian
– Ryazanian age for the unit. In this volume we present the organic
carbon isotope chemostratigraphy, cyclostratigraphy, lithostratigraphy
and sedimentology for the Member. A well preserved assemblage of
fossil echinoderms, the first ultrastructural information on the
lingulid brachiopod Lingularia and microfacies of nine seep carbonates
  are described. Comparative analyses of the marine reptile material
found in the Slottsmøya Member indicate a diverse assemblage of new
plesiosaurians (two new genera and three new species of plesiosauroids
and one new species of pliosaurid) and ichthyosaurians (two new genera
and species). Placed within a high-resolution stratigraphic framework,
the diverse invertebrate and vertebrate assemblage of the Slottsmøya
Lagerstätte provides an unparallelled opportunity to study the
evolution and paleoecology of a high-latitude, Mesozoic, marine
ecosystem.


==

Colymbosaurus svalbardensis (Persson, 1962) new combination (Plesiosauria)

****
Espen M. Knutsen, Patrick S. Druckenmiller & Jørn H. Hurum (2012)
Redescription and taxonomic clarification of  'Tricleidus'
svalbardensis based on new material
from the Agardhfjellet Formation (Middle Volgian).
Norwegian Journal of Geology 92 (2-3): 175-186
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/03/7_2401_0/NJG_2_3_2012_10_Knutsen_etal_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/03/8_2401_0/NJG_2_3_2012_10_Knutsen_etal_Pr.pdf

A partial postcranial plesiosaurian skeleton uncovered on Svalbard in
the winter of 1930-31 was described and named Tricleidus svalbardensis
Persson, 1962. However, the precise geographic location and
stratigraphic unit in which the skeleton was found were not published.
Recent fieldwork on Svalbard has uncovered two more plesiosaur
skeletons that are demonstrated herein to be conspecific with the 1931
taxon. These new specimens, along with recently discovered historic
documents produced by the excavation members of the 1930-31
expedition, reveal that the holotype specimen, PMO A 27745, was
recovered from the Upper Jurassic Slottsmøya Member of the
Agardhfjellet Formation, which is Middle Volgian in age. Collectively,
the Svalbard material is neither morphologically nor stratigraphically
consistent with the Callovian taxon Tricleidus Andrews, 1909 and is
here referred to Colymbosaurus Seeley, 1874 from the Kimmeridge Clay
Formation (Kimmeridgian to Tithonian) of the UK.

====

Spitrasaurus Knutsen, Druckenmiller & Hurum, 2012 (Plesiosauria)

*****

Espen M. Knutsen, Patrick S. Druckenmiller & Jørn H. Hurum (2012)
Two new species of long-necked plesiosaurians (Reptilia:
Sauropterygia) from the Upper Jurassic (Middle Volgian) Agardhfjellet
Formation of central Spitsbergen.
Norwegian Journal of Geology 92 (2-3): 187-212
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/03/3_2401_0/NJG_2_3_2012_11_Knutsen_etal_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/03/4_2401_0/NJG_2_3_2012_11_Knutsen_etal_Pr.pdf


At present, very little is known regarding the diversity and
morphological disparity of long-necked plesiosaurs in Tithonian-aged
(latest Jurassic) units globally. Here, we describe two species of a
new, long-necked plesiosaur genus Spitrasaurus from the Upper Jurassic
Slottsmøya Member of the Agardhfjellet Formation on Svalbard. The
holotype species of the genus, S. wensaasi, is the most complete
long-necked specimen found in this unit to date and is readily
diagnosed on the basis of having at least 60 cervical vertebrae
possessing a prominent lateral longitudinal ridge, as well as the
presence of a column of well-developed preaxial accessory ossicles in
the limbs. A second taxon, S. larseni, includes a partial skull that
broadly resembles the Kimmeridgian taxon Kimmerosaurus, but differs in
the morphology of its basioccipital, and in having a distinctive lower
jaw with a greatly elongate and strongly dorsally inflected
retroarticular process, among other characteristics. Each species of
Spitrasaurus can be differentiated on the basis of cervical vertebral
proportions and in the morphology of the cervical ribs, rib facets and
neural arches,  in addition to being stratigraphically separated. The
high number of cervical vertebrae in Spitrasaurus significantly
exceeds that for described Middle to Late Jurassic plesiosaurs, but is
comparable to some Cretaceous elasmosaurids. The Middle Volgian age of
this material helps to bridge the temporal and morphological gap
between better known Middle and Late Jurassic plesiosaurians from
Europe and Late Cretaceous taxa primarily known from North America.

====

Djupedalia Knutsen, Druckenmiller & Hurum, 2012 (Plesiosauria)

*****

Espen M. Knutsen, Patrick S. Druckenmiller & Jørn H. Hurum (2012)
A new plesiosauroid (Reptilia: Sauropterygia) from the Agardhfjellet
Formation (Middle Volgian) of central Spitsbergen, Norway.
Norwegian Journal of Geology 92 (2-3): 213-234
ISSN 029-196X.
low: 
http://www.geologi.no/data/f/0/21/03/0_2401_0/NJG_2_3_2012_12_Knutsen_etal_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/02/9_2401_0/NJG_2_3_2012_12_Knutsen_etal_Pr.pdf

At present, our knowledge of plesiosauroid diversity from the
uppermost Jurassic (Tithonian/Volgian) is very limited. Newly
discovered material from the Slottsmøya Member of the Agardhfjellet
Formation of central Spitsbergen, Svalbard, contributes significant
new information on this poorly known interval and helps bridge a
temporal gap between better known plesiosaurians from the older
Jurassic deposits of Europe, and Cretaceous of North America. The
partially articulated skeleton of a juvenile long-necked
plesiosaurian, PMO 216.839, is one of the most complete plesiosaur
fossils known from Spitsbergen and represents a new taxon, Djupedalia
engeri gen. et sp. nov. Whilst sharing some similarities with
previously described taxa from the Oxford Clay (Muraenosaurus,
Tricleidus, and Cryptoclidus) and the Kimmeridge Clay formations
(Kimmerosaurus) of England, the new taxon can be diagnosed by features
of the cervical vertebrae, including centrum proportions and
morphology, a very pronounced posterior shift in the neural spines
relative to the centrum, fused prezygapophyses and greatly elongated
postzygapophyses, as well as extremely short dorsal neural spines and
femora that are longer than the humeri. The new taxon can also be
distinguished from other newly-described plesiosauroids from Svalbard,
thus indicating that several plesiosaurian taxa existed at high
paleolatitudes during the Late Jurassic.


=====

Pliosaurus funkei Knutsen, Druckenmiller & Hurum, 2012

****
Espen M. Knutsen, Patrick S. Druckenmiller & Jørn H. Hurum (2012)
A new species of Pliosaurus (Sauropterygia: Plesiosauria) from the
Middle Volgian of central Spitsbergen, Norway.
Norwegian Journal of Geology 92 (2-3): 235-258
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/02/6_2401_0/NJG_2_3_2012_13_Knutsen_etal_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/02/5_2401_0/NJG_2_3_2012_13_Knutsen_etal_Pr.pdf


Eight seasons of fieldwork in the Upper Jurassic black shales of the
Slottsmøya Member of the Agardhfjellet Formation (Upper Jurassic;
Middle Volgian) in the Arctic archipelago of Svalbard have yielded
numerous skeletal remains of plesiosaurs and ichthyosaurs. Among the
new discoveries from the Slottsmøya Member are two very large
specimens of short-necked plesiosaurians. Dental and postcranial
morphology suggest that they represent a new species of the genus
Pliosaurus, a taxon known from several specimens of Kimmeridgian and
Tithonian-aged strata in England, France and Russia. Skeletal
dimensions of this new taxon suggest that it was one of the largest
members of the Pliosauridae and that it possessed comparatively longer
front limbs than other known pliosaurids. A morphometric analysis of
pliosaurids indicates they had a wide range of interspecific
variability in relative paddle lengths compared to body size.


=====

Espen M. Knutsen (2012)
A taxonomic revision of the genus Pliosaurus (Owen, 1841a) Owen, 1841b.
Norwegian Journal of Geology 92 (2-3): 259-276
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/02/2_2401_0/NJG_2_3_2012_14_Knutsen_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/02/1_2401_0/NJG_2_3_2012_14_Knutsen_Pr.pdf

The Late Jurassic genus Pliosaurus was erected by Owen in 1841a. Since
then numerous isolated bones and more complete skeletons have been
referred to various species within the genus, many based on
non-diagnostic material which has led to many uncertainties regarding
the taxonomic status of Pliosaurus. Here, the species of Pliosaurus,
their type and referred material are re-evaluated. Lack of distinctive
type material demands selection of a neotype for P. macromerus
(Philips, 1871) Lydekker, 1889a and a new neotype for P.
brachyspondylus (Owen, 1839) Eichwald, 1868. Four species are
recognised based on cranial tooth counts, cervical centrum morphology,
retroarticular morphology, and relative propodial length. Three
previously accepted named taxa are here considered invalid. This study
is also the first to collectively illustrate an accurate stratigraphic
provenance to, and what material is available from the main specimens
referred to Pliosaurus. The results of this work form a foundation on
which to build a more solid understanding of the diversity of this
genus.

====

Patrick S. Druckenmiller & Espen M. Knutsen (2012)
Phylogenetic relationships of Upper Jurassic (Middle Volgian)
plesiosaurians (Reptilia: Sauropterygia) from the Agardhfjellet
Formation of central Spitsbergen, Norway.
Norwegian Journal of Geology 92 (2-3): 277-­284
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/01/8_2401_0/NJG_2_3_2012_15_Druckenmiller_Knutsen_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/01/7_2401_0/NJG_2_3_2012_15_Druckenmiller_Knutsen_Pr.pdf

Plesiosaurian relationships have been subject to considerable debate
at both higher and lower levels within the clade. Recent fieldwork in
the Upper­ most Jurassic of the Agardhfjellet Formation on central
Spitsbergen has uncovered numerous ichthyosaurians and plesiosaurian
remains, including three new plesiosauroids, one new pliosauroid
referrable to Pliosaurus, and a previously described, re­classified
taxon. The phylogenetic relationships of these five taxa were
investigated based on data sets previously constructed for global
plesiosaurian relationships. Two specimens from the British Kimmeridge
Clay Formation and a Russian Volgian (uppermost Jurassic) taxon
referrable to Pliosaurus were added to the data matrix to improve the
phylogenetic resolution of this genus. The results yielded a tree
topology closely conforming to the traditional plesiosauroid and
pliosauroid dichotomy, nesting Leptocleidia within the latter.
Pliosaurus forms a monophyletic clade containing all currently
recognised species. The three new long­necked taxa form a monophyletic
sister group to the Cretaceous Elasmosauridae. These results should,
however, be considered preliminary pending the discovery of more
complete cranial material and adult specimens.

======

Lene Liebe & Jørn Harald Hurum (2012)
Gross internal structure and microstructure of plesiosaur limb bones
from the Late Jurassic, central Spitsbergen.
Norwegian Journal of Geology 92 (2-3): 285-309
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/01/4_2401_0/NJG_2_3_2012_16_Liebe_Hurum_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/01/3_2401_0/NJG_2_3_2012_16_Liebe_Hurum_Pr.pdf

Plesiosaur limb bones of four specimens from the Late Jurassic of
Svalbard have been studied to map gross internal structure and
microstructure and compare this to extant marine reptiles and mammals.
Two specimens; one juvenile (Djupedalia engeri) and one subadult
(Colymbosaurus svalbardensis) are from the Janusfjellet locality in
the Adventdalen Group, Janusfjellet Subgroup, Agardhfjellet Formation,
Slottsmøya Member, dated as MidVolgian; one adult (Colymbosaurus
svalbardensis) from the Agardhfjellet locality, also dated to
MidVolgian; and one juvenile (sp.indet.) of unknown stratigraphical
age. The bones examined are propodials, phalanges, mesopodials and
metapodials. This study is the first to describe the microstructure of
the latter two in plesiosaurs. The inner bone structure fits that of
an active marine animal. Many of the features in the present material
are often found in animals with rapid growth and high metabolism,
including secondary osteons, high vascularisation, pits on the outside
of the epiphysis, and woven and possibly fibro-lamellar bone in some
areas. The long bones have two endochondral cones in a periosteal
sheath, with a small medullary cavity. The propodials have a defined
and quite compact cortex in the subadult, a finding that rejects the
view that all plesiosaur bones became more porous through ontogeny.
There is a microstructural difference between bones from different
ontogenetic stages: juvenile bones lack remodelling and completely
ossified endochondral cones. One of the bones has a circumferential
vascular orientation with rings made of trabeculae, maybe resulting
from cyclic growth caused by seasonality, migration or ontogeny.

=====

Cryopterygius Druckenmiller, Hurum, Knutsen & Nakrem, 2012 (Ichthyosauria)
Palvennia Druckenmiller, Hurum, Knutsen & Nakrem, 2012 (Ichthyosauria)

****
Patrick S. Druckenmiller, Jørn H. Hurum, Espen M. Knutsen & Hans Arne
Nakrem (2012)
Two new ophthalmosaurids (Reptilia: Ichthyosauria) from the
Agardhfjellet Formation (Upper Jurassic: Volgian/Tithonian), Svalbard,
Norway.
Norwegian Journal of Geology 92 (2-3): 311-339
ISSN 029-196X
low: 
http://www.geologi.no/data/f/0/21/01/0_2401_0/NJG_2_3_2012_17_Druckenmiller_etal_Scr.pdf
high: 
http://www.geologi.no/data/f/0/21/00/9_2401_0/NJG_2_3_2012_17_Druckenmiller_etal_Pr.pdf

Ichthyosaur diversity near the Jurassic-Cretaceous boundary,
particularly from high paleolatitudes, is poorly known. Two recently
collected specimens of medium- to large-bodied ichthyosaurs from the
Slottsmøya Member of the Agardhfjellet, Svalbard, Norway represent two
new taxa of ophthalmosaurids. The holotype specimen of Cryopterygius
kristiansenae gen et sp. nov., PMO 214.578, is a nearly complete and
largely articulated skeleton. The specimen consists of a nearly
complete skull, the entire presacral and preflexural vertebral series,
numerous dorsal ribs and gastralia, an articulated pectoral girdle and
nearly complete forelimb, and an articulated left pelvic girdle and
hindlimb. The new taxon is diagnosed on a unique suite of features,
including a robust and moderately elongate rostrum, a reduced
supranarial process, an elongate maxilla that bears a high number of
teeth, the absence of a lacrimal-external naris contact, and an
anteroposteriorly broad postorbital bar possessing an unidentified
element (supratemporal?) that lies posterior to the quadratojugal.
Cryopterygius has 52 presacral vertebrae, a distinctive forelimb,
including a humerus that bears only two facets at its distal end, and
an articulated left pelvic girdle and hindlimb, which facilitates the
unequivocal orientation of the ophthalmosaurid femur. The holotype
specimen of Palvennia hoybergeti, SVB 1451, includes a nearly complete
skull and fragmented postcranial remains. It is diagnosed on its
relatively short rostrum, greatly enlarged orbit, narrow postorbital
bar, very large pineal foramen, basioccipital with broad extracondylar
area laterally, and a gracile stapedial shaft. The Slottsmøya
Lagerstätte is established as one of the most productive horizons for
Upper Jurassic ichthyosaurs and considerably expands our knowledge of
ophthalmosaurid diversity and distribution in the latest Jurassic.