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Cloudy With A Chance of New Papers
Sorry if any of these are duplicates of stuff already mentioned on the
list...I've been in England and largely away from e-mail since SVP...!
Taylor, M.A. 2009. Electronic publication of nomenclatural acts is inevitable,
and will be accepted by the taxonomic community with or without the endorsement
of the Code. Bulletin of Zoological Nomenclature 66(3):205-214.
Murakami, M., Hirayama, R., Hikida, Y., and Hirano, H. 2009. A theropod
dinosaur (Saurischia: Maniraptora) from the Upper Cretaceous Yezo Group of
Hokkaido, northern Japan. Paleontological Research 12(4):421-425.
Sepúlveda, J., Wendler, J.E., Summons, R.E., and Hinrichs, K.-U. 2009. Rapid
resurgence of marine productivity after the Cretaceous-Paleogene mass
extinction. Sciencce 326:129-132. doi: 10.1126/science.1176233.
ABSTRACT: The course of the biotic recovery after the impact-related disruption
of photosynthesis and mass extinction event at the Cretaceous-Paleogene
boundary has been intensely debated. The resurgence of marine primary
production in the aftermath remains poorly constrained because of the paucity
of fossil records tracing primary producers that lack skeletons. Here we
present a high-resolution record of geochemical variation in the remarkably
thick Fiskeler (also known as the Fish Clay) boundary layer at Kulstirenden,
Denmark. Converging evidence from the stable isotopes of carbon and nitrogen
and abundances of algal steranes and bacterial hopanes indicates that algal
primary productivity was strongly reduced for only a brief period of possibly
less than a century after the impact, followed by a rapid resurgence of carbon
fixation and ecological reorganization.
Schwarz-Wings, D., Meyer, C.A., Frey, E., Manz-Steiner, H.-R., and Schumacher,
R. 2009. Mechanical implications of pneumatic neck vertebrae in sauropod
dinosaurs. Proceedings of the Royal Society B: Biological Sciences. doi:
10.1098/rspb.2009.1275.
ABSTRACT: The pre-sacral vertebrae of most sauropod dinosaurs were surrounded
by interconnected, air-filled diverticula, penetrating into the bones and
creating an intricate internal cavity system within the vertebrae.
Computational finite-element models of two sauropod cervical vertebrae now
demonstrate the mechanical reason for vertebral pneumaticity. The analyses show
that the structure of the cervical vertebrae leads to an even distribution of
all occurring stress fields along the vertebrae, concentrated mainly on their
external surface and the vertebral laminae. The regions between vertebral
laminae and the interior part of the vertebral body including thin bony struts
and septa are mostly unloaded and pneumatic structures are positioned in these
regions of minimal stress. The morphology of sauropod cervical vertebrae was
influenced by strongly segmented axial neck muscles, which require only small
attachment areas on each vertebra, and pneumatic epithelia that are able to
resorb bone that is not mechanically loaded. The interaction of these soft
tissues with the bony tissue of the vertebrae produced lightweight, air-filled
vertebrae in which most stresses were borne by the external cortical bone.
Cervical pneumaticity was therefore an important prerequisite for neck
enlargement in sauropods. Thus, we expect that vertebral pneumaticity in other
parts of the body to have a similar role in enabling gigantism.
Bhullar, B.-A.S., and Bever, G.S. 2009. An archosaur-like laterosphenoid in
early turtles (Reptilia: Pantestudines). Breviora 518:1-11.
ABSTRACT: Turtles are placed with increasing consistency by molecular
phylogenetic studies within Diapsida as sister to Archosauria, but published
gross morphology?Cbased phylogenetic analyses do not recover this position.
Here, we present a previously unrecognized unique morphological character
offering support for this hypothesis: the presence in stem turtles of a
laterosphenoid ossification identical to that in Archosauriformes. The
laterosphenoid is a tripartite chondrocranial ossification, consisting of an
ossified pila antotica, pila metoptica, and taenia medialis + planum
supraseptale. It forms the anterior border of the exit for the trigeminal nerve
(V) and partially encloses the exits for cranial nerves III, IV, and II. This
ossification is unique to turtles and Archosauriformes within Vertebrata. It
has been mistakenly dismissed as anatomically dissimilar in these two groups in
the past, so we provide a complete description and detailed analysis of
correspondence between turtles and Archosauriformes in each of its
embryologically distinct components. A preliminary phylogenetic analysis
suggests other potential synapomorphies of turtles and archosaurs, including a
row or rows of mid-dorsal dermal ossifications.
Knight, T.K., Bingham, S., Grimaldi, D.A., Anderson, K., Lewis, R.D., and
Savrda, C.E. 2009. A new Upper Cretaceous (Santonian) amber deposit from the
Eutaw Formation of eastern Alabama, USA. Cretaceous Research. doi:
10.1016/j.cretres.2009.09.008.
ABSTRACT: A new amber-rich deposit has been identified in the Upper Cretaceous
(Santonian) Eutaw Formation exposed in eastern Alabama, U.S.A. Amber occurs as
common parautochthonous clasts and in direct association with conifer plant
parts in the lower part of a thin, laterally discontinuous, carbonaceous and
pyritiferous clay lens that was deposited in a tidal channel within a
transgressive estuarine bayhead-delta system. Organic inclusions are common in
amber clasts and include plant and fungal debris and terrestrial arthropod
remains. The latter include mites, a spider in association with its web, and
scale insects. Amber-plant associations and amber geochemistry indicate that
resins were derived from the Cupressaceae, virtually identical to the trees
that produced the Turonian-aged amber from central New Jersey, USA.
Kusuhashi, N., Hu, Y., Wang, y., Hirasawa, S., and Matsuoka, H. 2009. New
triconodontids (Mammalia) from the Lower Cretaceous Shahai and Fuxin
formations, northeastern China. Geobios. doi: 10.1016/j.geobios.2009.06.003.
ABSTRACT: The first triconodontids from Asia have been discovered from the
Lower Cretaceous (Aptian to Albian) Shahai and Fuxin formations in Liaoning
Province, northeastern China: Meiconodon lii gen. and sp. nov. and M.
setoguchii gen. and sp. nov. Meiconodon lii is characterized by molariform
teeth with a developed cusp d, an m3 with taller cusp a, an m4 with three
primary cusps of subequal height, the posteriorly decreasing transverse width
of the m4, and a considerably reduced m5. Meiconodon setoguchii is slightly
larger than M. lii, and characterized by a sharp labial cingulum on the m4, and
a less developed cusp d on the molariform teeth than M. lii. The extensive
interlocking system between molariforms, posteriorly recumbent primary
molariform cusps, and their great degree of asymmetry in occlusal view with
rounded labial faces and more angulate lingual faces in lateral view, indicate
that Meiconodon belongs to the triconodontid subfamily Alticonodontinae. These
new taxa are the first record of Triconodontidae from Asia, and of
Alticonodontinae outside North America, suggesting the occurrence of mammalian
faunal exchange between North America and Asia during or before the
Aptian-Albian.
Knoll, F. 2009. A large iguanodont from the upper Barremian of the Paris Basin.
Geobios. doi: 10.1016/j.geobios.2009.06.002.
ABSTRACT: The remains of an ornithopod dinosaur from the Upper Barremian (Lower
Cretaceous) of Auxerre (Burgundy, France) are described. They consist of
several vertebrae and a fragmentary scapula. Despite obvious morphological and
dimensional affinities with the species Iguanodon bernissartensis , the state
of the specimen does not allow any identification more precise than
Iguanodontia indet . Reappraisal of the French Upper Barremian record of
medium-sized and large ornithopods reveals that no specimen can be definitely
determined to the specific level.
Prauss, M.L. 2009. The K/Pg boundary at Brazos-River, Texas, USA -- an approach
by marine palynology. Palaeogeography, Palaeoclimatology, Palaeoecology. doi:
10.1016/j.palaeo.2009.09.024.
ABSTRACT: Two cores and one outcrop section from the Cretaceous/Palaeogen
(K/Pg) boundary interval at the Brazos-River area, Texas, USA, have been high
resolution sampled and analysed fully quantitatively by marine palynology. The
results have been compared and integrated with data from micropalaeontology,
sedimentology and isotope-geochemistry from the same sections. Within all three
sections, the K/Pg boundary, defined as the base of the P0 foraminifera zone
and the onset of a negative carbon isotope anomaly, closely corresponds to the
appearance of lowermost Danian organic-walled dinocysts. Based on various
palynological proxies as well as on sedimentologic features, a sequence
stratigraphic subdivision of the sections is proposed. From a synopsis of all
three sections, a long term, punctuated drop of relative sea-level is
indicated, starting at about the top of the Upper Cretaceous CF2 foraminifera
zone and reaching a minimum within the upper P1a zone of the Lower Palaeogene.
This is followed by a prominent transgression starting within the P1a/P1b
boundary interval. The “event deposit” (ED), a siliciclastic unit located well
below the base of the P0 foraminifera zone in the present sections, most
probably represents a combination of both episodic relative sea-level fall and
lag deposit due to initial transgression. It is preceded by significant
fluctuations of climatic boundary conditions, with cool climates correlating to
heavier δ 13C values and increased p/g ratio of dinocysts, suggestive of higher
marine primary productivity. Across the K/Pg boundary, a prominent increase and
spike of the warm-temperate waters dinocysts fraction is documented,
represented mainly by Trithyrodinium evittii, which is accompanied by climatic
warming and an episodic relative sea-level rise. Thus, prominent
paleo-environmental changes and sea-level fluctuations precede and coincide
with the K/Pg boundary proper. These data are inconsistent with a single
“catastrophic” impact as the cause for the K/Pg boundary eve!
nt, but s
uggest relative longer term environmental stress as finally leading to
End-Cretaceous crisis of the biosphere. Between the ED and the K/Pg boundary
proper, the gradual increase to peak abundance in trilete spores demonstrates a
significant time lag between these two horizons. According to the distinct
distribution of this peak abundance, it cannot be excluded that an
impact/tsunami event is related to the lower portion of the ED. In contrast, no
significant changes within most palynologic proxies are documented across the
yellow clay layer below the ED documented within one of the sections and
recently suggested as the original Chicxulub impact ejecta horizon. This
questions the impact origin of this horizon or, at least, suggests only little
consequences of this event on the ecosystem.
Roberts, E.M., O'Connor, P.M., Stevens, N.J., Gottfried, M.D., Jinnah, Z.A.,
Ngasala, S., Choh, A.M., and Armstrong, R.A. 2009. Sedimentology and
depositional environments of the Red Sandstone Group, Rukwa Rift Basin,
southwestern Tanzania: new insight into Cretaceous and Paleogene terrestrial
ecosystems and tectonics in sub-equatorial Africa. Journal of African Earth
Sciences. doi: 10.1016/j.jafrearsci.2009.09.002
ABSTRACT: The Red Sandstone Group (RSG) in the Rukwa Rift Basin of southwestern
Tanzania represents one of the only well-exposed, fossiliferous
Cretaceous-Paleogene continental sedimentary sequences in sub-equatorial
Africa. The significance of the RSG for reconstructing the paleoenvironmental
and paleoclimatic history of African ecosystems during these critical time
periods has been obfuscated by long-standing confusion and debate over the age
of the deposits. Detailed stratigraphic, sedimentologic, and paleontologic
investigations of the RSG conducted between 2002 and 2008 have produced a
wealth of new fossil discoveries and data on lithofacies, alluvial
architecture, sedimentary provenance, clay mineralogy and geochronology that
resolve the long-standing debate over the age of these deposits. This study
confirms the existence of an extensive middle Cretaceous sequence, herein named
the Galula Formation, and subdivided into the Mtuka and Namba members.
Moreover, we document the existence of a previously unrecognized late Paleogene
continental sequence termed the Nsungwe Formation, which is divided into the
Utengule and Songwe members. The Galula Formation represents a 600-3000 m thick
sequence of amalgamated, braided fluvial deposits that were deposited across a
large braidplain system via multiple parallel channels that had their source in
the highlands of Malawi and Zambia. The middle Cretaceous Dinosaur Beds of
Malawi are hypothesized to be at least partially correlative with the Galula
Formation, and represent proximal deposits of this large, northwest flowing,
trunk stream system. A moderately diverse terrestrial vertebrate fauna,
including multiple species of dinosaurs, crocodyliforms, turtles, fishes and
mammals have been recovered, along with a sparse aquatic molluscan fauna.
Lithofacies and clay mineralogy indicate that Cretaceous paleoclimate
ameliorated during deposition of the Galula Formation, transitioning from
tropical semi-arid to tropical humid conditions.
The 400+ m-thick late Oligocene Nsungwe Formation is temporally
constrained by concordant mammalian biostratigraphy, detrital zircon
geochronology and a radiometrically dated volcanic tuff capping the sequence
(not, vert, similar24.9 Ma). A significant change in depositional environments
occurs between the lower alluvial fan-dominated Utengule Member and the upper
fluvial and lacustrine-dominated Songwe Member. The Songwe Member preserves a
diverse terrestrial and aquatic vertebrate and invertebrate fauna, with
abundant ashfall and ashflow volcanic tuffs that were deposited in a semi-arid
wetland landscape during the late Oligocene. The Nsungwe Formation provides a
new window into the early tectonics and faunal transitions associated with
initiation of the “Modern” East African Rift System.
Ji, Q., Luo, Z.-X., Zhang, X., Yuan, C.-X., and Xu, L. 2009. Evolutionary
development of the middle ear in Mesozoic therian mammals. Science 326:278-281.
doi: 10.1126/science.1178501.
ABSTRACT: The definitive mammalian middle ear (DMME) is defined by the loss of
embryonic Meckel's cartilage and disconnection of the middle ear from the
mandible in adults. It is a major feature distinguishing living mammals from
nonmammalian vertebrates. We report a Cretaceous trechnotherian mammal with an
ossified Meckel's cartilage in the adult, showing that homoplastic evolution of
the DMME occurred in derived therian mammals, besides the known cases of
eutriconodonts. The mandible with ossified Meckel's cartilage appears to be
paedomorphic. Reabsorption of embryonic Meckel's cartilage to disconnect the
ear ossicles from the mandible is patterned by a network of genes and signaling
pathways. This fossil suggests that developmental heterochrony and gene
patterning are major mechanisms in homplastic evolution of the DMME.
Elzanowski, A., and Stidham, T.A. 2009. Morphology of the quadrate in the
Eocene anseriform Presbyornis and extant galloanserine birds. Journal of
Morphology. doi: 10.1002/jmor.10799.
ABSTRACT: Despite the notoriety, phylogenetic significance, and large number of
available specimens of Presbyornis, its cranial anatomy has never been studied
in detail, and its quadrate has been partly misinterpreted. We studied five
quadrates of Presbyornis that reveal features hitherto unknown in the
anseriforms but otherwise present in galliforms. As a result, we analyzed the
variable quadrate characters among all extant galloanserine families and
identified synapomorphies and other morphological variation among the major
galloanserine clades. In terms of quadrate morphology, Presbyornis is more
plesiomorphic than any extant anseriform (including the Anhimidae) and shares
ancestral galloanserine characters with the Megapodiidae, the earliest branch
of extant galliforms. The quadrate's morphology is inconsistent with the
currently accepted anseriform phylogeny that nests Presbyornis within the
crown-group as a close relative of the Anatidae. The presbyornithid quadrates
exhibit an unusual variation in the presence of a caudomedial pneumatic
foramen, which we interpret as a result of a discontinuous change in the growth
path of the pneumatic diverticulum. Another episode of morphogenetic imbalance
in the growth path of the pneumatic diverticulum may have accompanied the
disappearance of the basiorbital pneumatic foramen (along with the
pneumatization of the pterygoid) at the origin of the crown-group anseriforms.
This episode is marked by the striking individual variation in the presence and
location of pneumatic foramina in the mandibular part of the quadrate in the
Anhimidae.
Senter, P. 2009. Vestigial skeletal structures in dinosaurs. Journal of
Zoology. doi: 10.1111/j.1469-7998.2009.00640.x.
ABSTRACT: The existence of vestigial structures is one of the main lines of
evidence for macroevolution. Here I introduce a phylogenetic bracketing
approach to the identification of vestigial structures and apply it to
Dinosauria. According to this approach, a structure is considered vestigial if,
in comparison with its homolog in at least three successive outgroups, it is
reduced to one-third or less its size relative to adjacent structures and if at
least distally it has lost the specialized morphology present in the three
outgroups. This approach identifies fingers IV and V as vestigial in dinosaurs
in general, II?CV in sauropods, III in Tyrannosauridae and Caudipteryx, II and
III in Shuvuuia and I and III in modern birds. The entire forelimb distal to
the elbow is vestigial in Abelisauridae. Vestigial parts of the pelvic girdle
and hindlimb include the pubic shaft in Iguanodontia and Ceratopsia, the entire
pubis in Ankylosauria, the first metatarsal in derived Iguanodontia, the first
metatarsal shaft in Theropoda and the fifth toe in dinosaurs in general.
Derived Centrosaurinae and some Chasmosaurus exhibit vestigial supraorbital
horns. Some centrosaurines have a vestigial nasal horn. The antorbital cavity
is vestigial in Thyreophora, Iguanodontia and Ceratopsidae. I recommend that
this information be exploited to increase public awareness of the evidence for
macroevolution.
Vargas, A.O., Wagner, G.P., and Gauthier, J.A. 2009. Limusaurus and bird digit
identity. Nature Precedings.
ABSTRACT: Limusaurus is a remarkable herbivorous ceratosaur unique among
theropods in having digits II, III and IV, with only a small metacarpal vestige
of digit I. This raises interesting questions regarding the controversial
identity of avian wing digits. The early tetanuran ancestors of birds had
tridactyl hands with digital morphologies corresponding to digits I, II & III
of other dinosaurs. In bird embryos, however, the pattern of cartilage
formation indicates that their digits develop from positions that become digits
II, III, & IV in other amniotes. Limusaurus has been argued to provide evidence
that the digits of tetanurans, currently considered to be I, II and III, may
actually be digits II, III, & IV, thus explaining the embryological position of
bird wing digits. However, morphology and gene expression of the anterior bird
wing digit specifically resemble digit I, not II, of other amniotes. We argue
that digit I loss in Limusaurus is derived and thus irrelevant to understanding
the development of the bird wing.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT 84770 USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and dinogami@gmail.com
http://cactus.dixie.edu/jharris/
"Education is the only thing people
shell out a lot of money for...and
then do everything possible to avoid
getting their money's worth."
-- unknown