A new Late Cretaceous turtle, Angolachelys mbaxi gen. et sp. nov., from the Turonian (90 Mya) of Angola, represents the oldest eucryptodire from Africa. Phylogenetic analysis recovers Angolachelys mbaxi as the sister taxon of Sandownia harrisi from the Aptian of Isle of Wight, England. An unnamed turtle from the Albian Glen Rose Formation of Texas (USA) and the Kimmeridgian turtle Solnhofia parsonsi (Germany), are successively more distant sister taxa. Bootstrap analysis suggests those four taxa together form a previously unrecognized monophyletic clade of marine turtles, herein named Angolachelonia clade nov., supported by the following synapomorphies: mandibular articulation of quadrate aligned with or posterior to the occiput, and basisphenoid not visible or visibility greatly reduced in ventral view. Basal eucryptodires and angolachelonians originated in the northern hemisphere, thus Angolachelys represents one of the first marine amniote lineages to have invaded the South Atlantic after separation of Africa and South America.

THE CRETACEOUS SKELETON COAST OF ANGOLA JACOBS, Louis, SMU, Dallas, TX, USA; POLCYN, Michael, SMU, Dallas, TX, USA; MATEUS, Octávio, Museu da Lourinhã, Lourinhã, Portugal; SCHULP, Anne, Natuurhistorisch Museum Maastricht, Maastricht, Netherlands; NETO, André , Universidade Agostinho Neto, Luanda, Angola Cretaceous coastal sediments of Angola present a rich and diverse fauna of marine amniotes, including turtles, mosasaurs, and plesiosaurs. The abundance of mosasaurs in particular suggests a highly productive coastal area. Angola today lies at the northern limit of the Namibian Desert, the so-called Skeleton Coast, which results from prevailing southeasterly winds of the descending limb of the southern Hadley Cell sweeping across the African coast. The Benguela upwelling and a highly productive sea are found today off the Namibian Desert coast. However, the Benguela upwelling system, based on results of DSDP studies, is said to have originated in the late Neogene and therefore cannot explain the productivity found along the length of the West African coast. The explanation is found in the northward drift of Africa through the arid climate zone, and is demonstrated by the tracing of the paleogeographic position of fossil localities through time.

Clavicles and interclavicles are plesiomorphically present in Reptilia. However, several groups show reduction or even loss of these elements. Crocodylimorpha, e.g., lost the clavicles, whereas dinosaurs are generally interpreted to only preserve the clavicles, the theropod furcula representing an unique case of fused clavicles. In sauropods, reports of clavicles are relatively frequent in non-titanosauriforms. These elements are elongated, curved, and rather stout bones with a spatulate and a bifurcate end. However, they were always found as single bones, and differ from the relatively short and unbifurcated clavicles found articulated with the scapulae of basal sauropodomorphs. Elements from the Howe Quarry (Late Jurassic; Wyoming, USA) shed new light on these interpretations. Besides the elongated, curved bones (herein named morphotype A), also pairs of symmetric, L-shaped bones were recovered (morphotype B), associated with diplodocid dorsal and cervical vertebrae. Elements resembling morphotype B - articulated between the scapulae - have recently been reported from a diplodocid found near Tensleep, Wyoming. Taphonomic evidence, as well as the fact that they were preserved in symmetrical pairs, therefore implies that morphotype B represents the true sauropod clavicles. Contrary to earlier reports, morphotype A elements from the Howe Quarry, as well as of previously reported specimens show a symmetry plane following the long axis of the elements. It is thus possible that the morphotype A elements were single bones from the body midline. The only such element present in the pectoral girdle of tetrapods are the interclavicle and the furcula. Comparison with crocodilian and lacertiform interclavicles indicates that the bifurcate end of the sauropod elements might represent the reduced transverse processes of the anterior end, and the spatulate end would have covered the coracoids or sternal plates ventrally. The presence of both clavicles and interclavicles in the pectoral girdle stiffens the anterior trunk, and enhances considerably its stability. Such an enforcement might have been needed in diplodocids due to the strong lateral forces induced to the fore-limbs by the posteriorly placed center of mass (due to shorter fore- than hind-limbs), as well as lateral movements of the enormously elongated necks and tails. The absence of clavicles and interclavicles in titanosauriforms coincides with the development of wide-gauge locomotion style. The presence of interclavicles in sauropods supports the recently proposed homology of the furcula with the interclavicle, instead of representing fused clavicles. Interclavicles were thus not lost, but may have remained cartilaginous or have yet to be found in basal dinosauriforms.

A newly discovered dinosaur track-assemblage from the Upper Jurassic Lourinha˜ Formation (Lusitanian Basin, central-west Portugal), comprises medium- to large-sized sauropod tracks with well-preserved impressions of soft tissue anatomy, stegosaur tracks and tracks from medium- to large-sized theropods. The 400-m-thick Lourinha˜ Formation consists of mostly aluvial sediments, deposited during the early rifting of the Atlantic Ocean in the Kimmeridgian and Tithonian. The stratigraphic succession shows several shifts between flood-plain mud and fluvial sands that favour preservation and fossilization of tracks. The studied track-assemblage is found preserved as natural casts on the underside of a thin bivalve-rich carbonate bed near the Tithonian–Kimmeridgian boundary. The diversity of the tracks from the new track assemblage is compared with similar faunas from the Upper Jurassic of Asturias, Spain and the Middle Jurassic Yorkshire Coast of England. The Portuguese record of Upper Jurassic dinosaur body fossils show close similarity to the track fauna from the Lourinha˜ Formation.

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NEW SPECIMENS OF ANGOLASAURUS BOCAGEI AND COMMENTS ON THE EARLY RADIATIONS OF PLIOPLATECARPINE MOSASAURS POLCYN, Michael, SMU, Dallas, TX, USA; JACOBS, Louis, SMU, Dallas, TX, USA; MATEUS, Octávio, Museu da Lourinhã, Lourinhã, Portugal; SCHULP, Anne, Natuurhistorisch Museum Maastricht, Maastricht, Netherlands New, well preserved material of the Turonian mosasaur Angolasaurus bocagei from the Tadi Beds of the Itombe Formation in northern Angola, allows detailed redescription of its morphology and reassessment of its phylogenetic relationships. Angolasaurus had been previously referred to the genus Platecarpus; however, phylogenetic analysis confirms the valid taxonomic status of A. bocagei, and reconstructs that taxon within a clade that also includes the genera Selmasaurus and Ectenosaurus. These forms are united by an elaborated infrastapedial process of the quadrate and a unique ridge-like descending process of the parietal forming the supraoccipital articulation, but also retain a relatively plesiomorphic configuration of the braincase. That clade is united with all other plioplatecarpines by a number of derived characters including the presence of a novel basicranial circulation pattern. In Africa, North and South America, early plioplatecarpines are known by the Middle Turonian and Angolasaurus and closely related forms appear by the Upper Turonian. Selmasaurus and Ectenosaurus are a rare faunal component of the Santonian and Campanian of North America. Platecarpus planifrons appears in the Coniacian of North America and represents the plesiomorphic condition of the clade containing the remaining species of Platecarpus and Plioplatecarpus, that appears in the Santonian and persist until the end of the Cretaceous, reaching global distribution. The temporal and geographic distribution of these radiations suggest influence of paleogeography and eustatic sea levels.

The Upper Jurassic Lourinhã Formation (Lusitanian Basin, Portugal) contains a diverse dinosaur fauna comprising theropods, sauropods, stegosaurs, ankylosaurs and several genera of ornithopods. The sedimentology in the area favours preservation of tracksways, and tracks from most of the dinosaurs are also represented by skeletal remains. During fieldwork in the summer of 2003 a new, large, tridactyl track was found at the beach of Vale Frades, approximately 6 km north of Lourinhã (central west Portugal). The track was found together with a stegosaur track on a clay bed exposed within the intertidal zone. Due to the immediate danger of erosion, the track was collected and is now on display at Museu da Lourinhã. The track is 70 cm long and 69 cm wide, the toes are short and broad, with indications of short blunt claws, and there is a high angle of divarication between the outer digits. The shape and dimensions of the track identifies it as deriving from an ornithopod dinosaur with an estimated hip height around three metres. Although very large ornithopods are known from the Cretaceous, the largest known Jurassic ornithopod is Camptosaurus from North America, and the largest known from Portugal is the camptosaurid Draconyx loureiroi. Neither of these reached the body size suggested by the new track. So far the track described herein is the only evidence for a Jurassic ornithopod of that size.

Here we describe a new partial sauropod skeleton from the late Kimmeridgian (Late Jurassic) of the Lourinhã Formation, central west Portugal. The closely associated specimen comprises a complete tooth (with root), a fragment of cervical neural arch, an anterior chevron, and an almost complete right pectoral girdle and forelimb. The new sauropod, Zby atlanticus, n. gen. et sp., can be diagnosed on the basis of four autapomorphies, including a prominent posteriorly projecting ridge on the humerus at the level of the deltopectoral crest. Nearly all anatomical features indicate that Zby is a non-neosauropod eusauropod. On the basis of several characters, including tooth morphology, extreme anteroposterior compression of the proximal end of the radius, and strong beveling of the lateral half of the distal end of the radius, Zby appears to be closely related to Turiasaurus riodevensis from approximately contemporaneous deposits in eastern Spain. However, these two genera can be distinguished from each other by a number of features pertaining to the forelimb. Whereas previously described Late Jurassic Portuguese sauropods show close relationships with taxa from the contemporaneous Morrison Formation of North America, it appears that turiasaurians were restricted to Europe. All adult sauropods recovered in the Late Jurassic of Portugal thus far are very large individuals: it is possible that the apparent absence of small- or medium-sized adult sauropods might be related to the occupation of lower-browsing niches by non-sauropods such as the long-necked stegosaur Miragaia longicollum.

The basal part of the Triassic-Jurassic (Rhaetian-Sinemurian) Kap Stewart Formation, exposed at Jameson Land, East Greenland, yields an extensive coprolite collection from black, parallel-laminated mudstone (“paper shale”), representing an open lacustrine system. Preliminary investigations show three different types of coprolites: elongated cylindrical masses, composed of irregularly wrapped layers; elongated cylindrical masses with constriction marks; and spirally-coiled specimens.

Although the Late Jurassic of Portugal has provided abundant dinosaur fossils, material from the Early Cretaceous is scarce. This paper reports new cranial and postcranial material of the theropod dinosaur Baryonyx walkeri found in the Barremian (Papo Seco Formation) of Portugal. This specimen, found at Praia das Aguncheiras, Cabo Espichel, consists of a partial dentary, isolated teeth, pedal ungual, two calcanea, presacral and caudal vertebrae, fragmentary pubis, scapula, and rib fragments. It represents the most complete spinosaurid yet discovered in the Iberian Peninsula and the most complete dinosaur from the Early Cretaceous of Portugal. This specimen is confidently identified as a member of Baryonychinae due to the presence of conical teeth with flutes and denticles in a dentary rosette. The specimen ML1190 shares the following characteristics with Baryonyx walkeri: enamel surface with small (nearly vertical) wrinkles, variable denticle size along the carinae, 6–7 denticles per mm, wrinkles forming a 45 degree angle near the carinae, and tooth root longer than crown. In addition, dubious taxa based on teeth morphology such as Suchosaurus cultridens (Owen, 1840–1845), and Suchosaurus girardi (Sauvage 1897–98; Antunes & Mateus 2003) are discussed, based on comparisons with well-known material such as Baryonyx walkeri Charig & Milner, 1986. Suchosaurus cultridens and S. girardi are considered as nomina dubia due to the lack of diagnostic apomorphies, but both specimens are referred to Baryonychinae incertae sedis.

Several well preserved clutches of dinosaurs have been discovered in the upper Kimmeridgian/ Tithonian of Lourinhã (Estramadur Province, Portugal). Some eggs of one clutch contained embryo elements of a theropod dinosaur. The egg-shell resembles that of eggs which have been discovered in the Upper Jurassic of Colorado

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Book of abstracts of the 5th Symposium on Mesozoic and Decapod Crustaceans

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Modern marine species populations are often evaluated in terms of bottom-up, resource limited structure, or top-down, predator controlled structure. In a larger timeframe, investiga- tion of physical drivers in marine tetrapod evolution relies on the recognition of patterns and the correlation in timing of physical events with biotic change. However, it has been dem- onstrated through the study of fossil cetaceans that a broader deep-time perspective within a top-down or bottom-up framework is informative. Here we examine the fossil record of &UHWDFHRXV PDULQH WHWUDSRGV LQ $QJROD WR GLVFHUQ SDWWHUQV WKDW PD\ UHÀHFW SK\VLFDO GULYHUV RI evolution, and that are also relevant to population structure. In modern marine ecosystems, GLVWULEXWLRQ SDWWHUQV UHÀHFWLQJ SULPDU\ SURGXFWLYLW\ DUH LQGLFDWLYH RI ERWWRP?XS FRQWURO? ,Q the fossil record, productivity-controlled distribution patterns can also be perceived. Physi- cal parameters resulting in environmental stability, sea-level change, oceanic anoxic events, paleoclimate, and paleogeography are examined in comparison with taxonomic diversity and life history patterns. Mosasaurs originated during a time of high global temperatures and shallow temperature gradients. As upper-trophic-level species of modest size and plesiopedal limb structure (capable of terrestrial locomotion), early mosasaurs were subject to both top- down and bottom up pressures. The attainment of larger size coupled with emigration and biogeographic distribution in areas of high primary productivity, and niche differentiation VKRZQ E\ 13C values, indicate bottom-up pressures. Productivity along the African coast since the formation of the Atlantic Ocean facilitated the co-occurrence of diverse marine tetrapods through time, and has culminated today in the Benguela large marine ecosystem. Just as the current Benguela ecosystem has tetrapod species populations dominated by both bottom-up (cetaceans) and top-down strategies (sea birds and pinnipeds), so too did the Cre- taceous community, with mosasaurs and plesiosaurs having predominantly bottom-up popu- lation structure, while sea turtles and pterosaurs were more subject to top-down pressures.

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Upper Jurassic nesting site from Paimogo (Lourinhã, Portugal) yielded the oldest dinosaur theropod embryos ever found. Numerous bones, including skull bones, from the skeleton of these embryos have been collected. The study of bones and embryos offers the possibility to learn more on the early life of theropod dinosaurs.