Publications in the Year: 2013

Book

Pais, {JJC}, Kullberg {JCR}, de} Melo {JMDJ, Mateus O, de} Almeida {JA.  2013.  Arrábida - al-rábita, 1. : Associação de Municípos da Região de Lisboa Abstract

The publication of the present work - rightly designated as the book of Arrabida's nomination file for inscription on the World Heritage list - has for all of us a special significance as it represents, in a sense, the culmination of a complex, challenging and rewarding process. As is widely known, the Arrábida is included since 2004 in UNESCO's Portuguese tentative list, with AMRS being one of this process' promoters. It wouldn't be appropriate to describe here all the details, but it is fair to say that since 2004 to the present day, we've come a long way in recovering and valuing the Arrábida. It is with sincere satisfaction that we can say: our knowledge of the Property is now deeper, up to date and much more accurate, doing justice to the exceptional values contained within the Arrábida - which is well expressed in the work now published, based on researches and works of the highest scientific value. This is also a regional development project, to value our lands, people and the natural and cultural heritage. The Setúbal's Peninsula is a region that contains within its territory a vast natural and cultural heritage, being the Arrábida one of the most beautiful and significant natural areas in the Mediterranean. The Arrábida Mountain is a place with its own identity, being the result of a long history of Man's adaptation to Nature. It is a place of unmistakable aesthetic beauty, a unique place where nature and culture intertwine; it is a place of contrasts, of land and sea, sky and mountains, a place of combined actions by Man and Nature. Place of vibrant social practices, of rituals and festivals, of knowledge, of representations and expressions, of instruments, objects and artifacts. Place with a history that must be preserved and bequeathed to future generations. Place with monuments of vanished civilizations, but also of living traditions. These are some of the values supporting the Arrábida's nomination for the World's Heritage list. It is a complex and demanding nomination file, which this work is an illustrative sample of. A mixed application - as it includes both the natural and cultural heritage - which, given the richness and uniqueness of the Property in question, is fully justified. It is our profound conviction that this Nomination streamlines the potential of our region, bringing benefits not only to the local population, but also to the whole country. To that extent, it is also a sign of hope and confidence showing that it is possible to build a different future; that by investing in our people, in their abilities, knowledge and traditions, it is possible to create a sustainable development; that is possible to leave for future generations a legacy of which we are proud of having worked on. To be able enjoy this magnificent edition is a step in that direction.

Coelho,(ed)C, et al.  2013.  Arrábida - al-rábita. , Lisboa, 229 pp.: Associação de Município da Região de Setúbal

Book Chapter

Kullberg, JC, Rocha RB, Soares AF, Rey J, Terrinha P, Azerêdo AC, Callapez P, Duarte, L.V., Kullberg MC, Martins L, Miranda JR, Alves C, Mata J, Madeira J, Mateus O, Moreira M, Nogueira CR.  2013.  A Bacia Lusitaniana: Estratigrafia, Paleogeografia e Tectónica. Geologia de Portugal no contexto da Ibéria. Volume II. (Dias, R. Araújo, A, Terrinha, P. and Kullberg, J. C., Ed.).:195-350., Lisboa: Escolar Editorakullberg_et_al_2013_a_bacia_lusitaniana.pdf
da} Rocha, {REB, Kullberg {JCR}, Mateus O.  2013.  A Bacia Lusitaniana: Estratigrafia, Paleogeografia e Tectónica, 1. Geologia de Portugal no contexto da Ibéria. (Dias, Araújo, R., A, Terrinha, P., Kullberg, {J. C.}, Eds.).:195–347.: Escolar Editora Abstract
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Conference Paper

Mateus, O.  2013.  First definitive association between embryonic Allosaurus bones and prismatoolithus eggs in the Morrison Formation (Upper Jurassic, Wyoming, USA), 1. Journal of Vertebrate Paleontology. :101. Abstract

Despite more than a century of collecting, resulting in one of the best-studied vertebrate fossil records anywhere in the world, the Upper Jurassic Morrison Formation has produced surprisingly few examples of dinosaur eggs associated with embryonic remains. Even more puzzling, none of these seem to pertain to the theropod Allosaurus, one of the most common and best-understood dinosaur taxa in the formation. Here we report on a dinosaur nest site that has produced both abundant prismatoolithid eggshell and embryonic (or perinatal) bones of Allosaurus from Fox Mesa, Wyoming. This represents the first such discovery for any theropod in the Jurassic of North America. The nest is heavily weathered but contains a few ellipsoid eggshell clusters that suggest an egg size of about 8 x 6.5 cm. Study of the eggshell morphology and microstructure confirms that a single egg type is present throughout, which is indistinguishable from Prismatoolithus coloradensis. All of the identifiable embryonic materials pertain to theropods, and two premaxillae specimens show the five alveoli diagnostic for Allosaurus among Morrison theropods. This confirms the theropod origin of Prismatoolithus eggs and implicates Allosaurus as the specific Morrison parent taxon. As a result, it is now possible to assign several previous discoveries of dinosaur eggs and potential nests to Allosaurus, including the isolated egg from the Cleveland-Lloyd Quarry. This discovery also calls into question prior assignments of Prismatoolithus eggs to ornithopods, and suggests that more detailed study of such sites is warranted. Prismatoolithus eggshells are also associated with the Upper Jurassic theropod Lourinhanosaurus from Portugal, along with larger embryos that exhibit four premaxillary alveoli.

Mateus, O.  2013.  Cathetosaurus as a valid sauropod genus and comparisons with Camarasaurus, 1. Journal of Vertebrate Paleontology. :173. Abstract
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Mateus, O.  2013.  Crocodylomorphs from the Mesozoic of Portugal and a new skull of eusuchian from the Late Cretaceous. 2013 Hwaseong International Dinosaurs Expedition Symposium, pp.66-67.. , Hwaseong, South Korea Abstractmateus_2013_crocodylomorphs_portugal_new_skull.pdf

The diversity of fossil crocodylomorphs in Portugal is high, with occurrence as old as Mystriosaurus (=Steneosaurus) bollensis from the Lower Jurassic. The Late Jurassic forms are the better documented, and include the following taxa: Machimosaurus hugii, Lisboasaurus estesi Seiffert, 1973, Lusitanisuchus mitrocostatus Seiffert, 1975; Schwarz & Fechner 2004, Theriosuchus guimarotae Schwarz and Salisbury 2005, Cf. Alligatorium, Goniopholis baryglyphaeus, and a crocodylomorph-like eggs in dinosaur nests (Mateus et al., 1998; Ricqlès et al., 2001). From the Lower Cretaceous were reported a few dinosaurs but its record is strangely scarce in crocodylomorphs (Mateus et al., 2011). The Upper Cretaceous crocodiles show a large diversity, but it is mostly based in fragmentary material that require revision, such as “Crocodylus” blavieri? Grey from the Upper Campanian - Maastrichtian of Viso, near Aveiro (initially reported by Sauvage 1897-98), Goniopholis cf. crassidens Owen 1841 and Oweniasuchus pulchelus Jonet 1981. Moreover there is a fascinating, but poorly understood, crocodylomorph diversity in the Cenomanian of Portugal, documented by fragmentary specimens that have been doubtfully assigned to Thoracosaurus Leidy 1852 of the Middle Cenomanian of Cacém, to the nomen dubium Oweniasuchus lusitanicus Sauvage 1897-98 (interpreted as a mesosuchian goniopholid) based in a fragmentary mandible from the Campanian-Maastrichtian, and also from the Middle Cenomanian of Portugal, Buffetaut and Lauverjat (1978) report an fragmentary unidentified possible dyrosaurid from Nazaré. All this specimens are too incomplete to be compared with the specimen here described. In contrast, Cenozoic crocodiles of Portugal are often known after complete skulls and several individuals. The taxa list include Iberosuchus macrodon (Lower to Middle Eocene), Tomistoma calaritanus (Early Miocene) and T. lusitanica (Burdigalian-Helvetian), and Diplocynodon sp. (Antunes, 1961, 1987, 1994).
At least, two different morphotypes of crocodylomorph eggs from the Late Jurassic of Lourinhã Formation are also known.
A new specimen here reported of crocodile based in a partial skull and mandible (ML1818) from the Uppermost Middle Cenomanian platform carbonates of Baixo Mondego, west central Portugal (Tentúgal Fm., Callapez, 2004). The taxon is phylogenetically positioned as a basal Eusuchia, due to the choanae enclosed by the pterygoid, and closely related with stem Crocodylia and Borealosuchus. This specimen represents the only well documented and valid eusuchian species in the Cenomanian of Europe and is the oldest representative of an eusuchian crocodylomorph, with the exception for the Barremian Hylaeochampsa vectiana.

Mateus, O, Neto de Carvalho C, Klompmaker AA.  2013.  Decapod crustacean body and ichnofossils from the Mesozoic of Portugal, 25–27 June 2013. 5th Symposium on Mesozoic and Cenozoic Decapod Crustaceans. , Warszawa: Polish Geological Institute − National Research Institute & AGH University of Science and Technologymateus_et_al_2013_crustacea_mesozoic_portugal_5th_decapod_crustaceans_meeting_2013.pdf

Conference Proceedings

Jacobs, LL, Myers TS, Goncalves AO, Graf JF, Jacobs BF, KAPPELMAN JW, Mateus O, Polcyn MJ, RASBURY ET, Vineyard DP.  2013.  Cabinda revisited: age and environment of new Cenozoic vertebrate fossils from northern Angola. Geological Society of America Abstracts with Programs. Vol. 45, No. 7, p.0.
Carrano, M, Mateus O, Mitchell J.  2013.  First definitive association between embryonic Allosaurus bones and prismatoolithus eggs in the Morrison Formation (Upper Jurassic, Wyoming, USA). Annual Meeting of Vertebrate Paleontology. :101.: Journal of Vertebrate Paleontology, Program and Abstracts, 2013 Abstractcarrano_mateus_mitchell_2013_allosaurus_embryos_morrison_svp_abstract.pdf

Despite more than a century of collecting, resulting in one of the best-studied vertebrate fossil records anywhere in the world, the Upper Jurassic Morrison Formation has produced surprisingly few examples of dinosaur eggs associated with embryonic remains. Even more puzzling, none of these seem to pertain to the theropod Allosaurus, one of the most common and best-understood dinosaur taxa in the formation. Here we
report on a dinosaur nest site that has produced both abundant prismatoolithid eggshell and embryonic (or perinatal) bones of Allosaurus from Fox Mesa, Wyoming. This represents the first such discovery for any theropod in the Jurassic of North America. The nest is heavily weathered but contains a few ellipsoid eggshell clusters that suggest an egg size of about 8 x 6.5 cm. Study of the eggshell morphology and microstructure confirms that a single egg type is present throughout, which is indistinguishable from Prismatoolithus coloradensis. All of the identifiable embryonic materials pertain to theropods, and two premaxillae specimens show the five alveoli diagnostic for Allosaurus among Morrison theropods. This confirms the theropod origin of Prismatoolithus eggs and implicates Allosaurus as the specific Morrison parent taxon. As a result, it is now possible to assign several previous discoveries of dinosaur eggs and potential nests to Allosaurus, including the isolated egg from the Cleveland-Lloyd Quarry. This discovery
also calls into question prior assignments of Prismatoolithus eggs to ornithopods, and suggests that more detailed study of such sites is warranted. Prismatoolithus eggshells are also associated with the Upper Jurassic theropod Lourinhanosaurus from Portugal, along with larger embryos that exhibit four premaxillary alveoli.

Polcyn, MJ, Jacobs LL, Mateus O, Schulp AS, Strganac C, Araújo R, Graf JF, Vineyard D, Myers TS.  2013.  A marine vertebrate assemblage from the Campanian-Maastrichtian boundary at Bentiaba, Angola. Geological Society of America Abstracts with Programs. Vol. 45, No. 7, p.0. polcyn_et_al_2013_abstract__a_marine_vertebrate_assemblage_from_the_campanian-maastrichtian_boundary_at_bentiaba_angola_2013__gsa_27-30_october_2013.pdf
Strganac, C, Jacobs LL, Ferguson KM, Polcyn MJ, Mateus O, Schulp AS, Morais ML.  2013.  Late Cretaceous marine reptiles and cooling at the South Atlantic coast inferred through stable oxygen isotopes of Inoceramus from the Namibe Basin, Angola. Geological Society of America Abstracts with Programs. Vol. 45, No. 7, p.0.
Salminen, J, Dinis J, Mateus O.  2013.  Preliminary magnetostratigraphy for Jurassic/Cretaceous transition in Porto da Calada, Portugal. In: Veikkolainen, T., Suhonen, K., Näränen, J., Kauristie, K., and Kaasalainen, S. (eds.). XXVI Geofysiikan päivät,. :119-122., May 21-22 2013 in Helsinkisalminen.johanna_gfp2013_portugal_preliminary_magnetostratigraphy_for_jurassic_cretaceous_transition_in.pdf
Brusatte, SL, Butler RJ, Mateus O, Steyer JS, Whiteside JH.  2013.  Terrestrial vertebrates from the Late Triassic of Portugal: new records of temnospondyls and archosauriforms from a Pangaean rift sequence. 61st Symposium on Vertebrate Palaeontology and Comparative Anatomy. :15-16., Edinburgh Abstractbrusatte_et_al_2013_triassic_algarve_portugal_temnospondyls_svpca.org_years_2013_edinburgh_abstracts.pdf

The Late Triassic (ca. 237-201.5 million years ago) was a transitional interval in the evolution of terrestrial ecosystems, during which ‘modern’ clades such as archosaurs and mammals were radiating while ‘archaic’ groups such as temnospondyl amphibians and basal synapsids remained abundant. Little is known about the Triassic terrestrial (nonmarine) vertebrates of the Iberian Peninsula. The Algarve Basin of southern Portugal is an extensional rift basin formed during the breakup of Pangaea, which is filled with terrestrial, lacustrine, and marginal marine siliciclastics of the Grés de Silves Formation, interbedded with CAMP basalts that mark the end-Triassic extinction (radioisotopically dated to ~198-201.5 Ma). Since 2009, our field project in the Algarve has discovered numerous vertebrate specimens within the Grés de Silves, including a monodominant bonebed containing hundreds of specimens of metoposaurids, a peculiar group of temnospondyls that filled crocodile-like predatory niches in lacustrine and fluvial environments. These specimens appear to belong to a new species of Metoposaurus, similar to M. diagnosticus and M. krasiejowensis from central Europe but possessing several putative autapomorphies of the braincase and lower jaw. We also discovered a mandible of a phytosaur, the first specimen of these long-snouted, semi-aquatic archosauriforms from the Iberian Peninsula. These discoveries of characteristic Carnian Norian taxa indicate that the fossil-bearing portion of the Grés de Silves is Late Triassic in age, and provide further evidence that metoposaurids and phytosaurs commonly occurred together in low palaeolatitudes during this time.

Journal Article

Mannion, PD, Upchurch P, Barnes RN, Mateus O.  2013.  Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society. 168:98-206. Abstractmannion_et_al_2013_sauropod_lusotitan_portugal.pdfWebsite

Titanosauriforms represent a diverse and globally distributed clade of neosauropod dinosaurs, but their inter-relationships remain poorly understood. Here we redescribe Lusotitan atalaiensis from the Late Jurassic Lourinhã Formation of Portugal, a taxon previously referred to Brachiosaurus. The lectotype includes cervical, dorsal, and caudal vertebrae, and elements from the forelimb, hindlimb, and pelvic girdle. Lusotitan is a valid taxon and can be diagnosed by six autapomorphies, including the presence of elongate postzygapophyses that project well beyond the posterior margin of the neural arch in anterior-to-middle caudal vertebrae. A new phylogenetic analysis, focused on elucidating the evolutionary relationships of basal titanosauriforms, is presented, comprising 63 taxa scored for 279 characters. Many of these characters are heavily revised or novel to our study, and a number of ingroup taxa have never previously been incorporated into a phylogenetic analysis. We treated quantitative characters as discrete and continuous data in two parallel analyses, and explored the effect of implied weighting. Although we recovered monophyletic brachiosaurid and somphospondylan sister clades within Titanosauriformes, their compositions were affected by alternative treatments of quantitative data and, especially, by the weighting of such data. This suggests that the treatment of quantitative data is important and the wrong decisions might lead to incorrect tree topologies. In particular, the diversity of Titanosauria was greatly increased by the use of implied weights. Our results support the generic separation of the contemporaneous taxa Brachiosaurus, Giraffatitan, and Lusotitan, with the latter recovered as either a brachiosaurid or the sister taxon to Titanosauriformes. Although Janenschia was recovered as a basal macronarian, outside Titanosauria, the sympatric Australodocus provides body fossil evidence for the pre-Cretaceous origin of titanosaurs. We recovered evidence for a sauropod with close affinities to the Chinese taxon Mamenchisaurus in the Late Jurassic Tendaguru beds of Africa, and present new information demonstrating the wider distribution of caudal pneumaticity within Titanosauria. The earliest known titanosauriform body fossils are from the late Oxfordian (Late Jurassic), although trackway evidence indicates a Middle Jurassic origin. Diversity increased throughout the Late Jurassic, and titanosauriforms did not undergo a severe extinction across the Jurassic/Cretaceous boundary, in contrast to diplodocids and non-neosauropods. Titanosauriform diversity increased in the Barremian and Aptian–Albian as a result of radiations of derived somphospondylans and lithostrotians, respectively, but there was a severe drop (up to 40%) in species numbers at, or near, the Albian/Cenomanian boundary, representing a faunal turnover whereby basal titanosauriforms were replaced by derived titanosaurs, although this transition occurred in a spatiotemporally staggered fashion.

Schulp, AS, Polcyn MJ, Mateus O, Jacobs LL.  2013.  Two rare mosasaurs from the Maastrichtian of Angola and the Netherlands. Geologie en Mijnbouw/Netherlands Journal of Geosciences. 92:3-10., Number 1 Abstract
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Bianucci, G, Miján I, Lambert O, Post K, Mateus O.  2013.  Bizarre fossil beaked whales (Odontoceti, Ziphiidae) fished from the Atlantic Ocean floor off the Iberian Peninsula. Geodiversitas. 35(1):105-153. Abstractbianucci_et_al_2013_fossil_beaked_whales_iberian_peninsula.pdf

Forty partial fossil skulls belonging to beaked whales (Cetacea, Odontoceti, Ziphiidae) were collected by trawling and long-line fishing on Neogene (probably Late Early to Middle Miocene) layers of the Atlantic floor off the coasts of Portugal and Spain (Asturias and Galicia). e systematic study of the most diagnostic Iberian specimens, those preserving the rostrum and the dorsal part of the cranium, led to the recognition of two new genera (Globicetus n. gen. and Imocetus n. gen.) and four new species (Choneziphius leidyi n. sp., G. hiberus n. gen., n. sp., I. piscatus n. gen., n. sp., and Tusciziphius atlanticus n. sp.).
Based on the matrix of a previous work, the phylogenetic analysis places all the new taxa in the subfamily Ziphiinae Gray, 1850. More fragmentary specimens are tentatively referred to the genera Caviziphius Bianucci & Post, 2005 and Ziphirostrum du Bus, 1868. Among these new ziphiids, extremely bizarre skull morphologies are observed. In G. hiberus n. gen., n. sp. the proximal portion of the rostrum bears a voluminous premaxillary spheroid. In T. atlanticus n. sp. a medial premaxillary bulge is present on the rostrum; together with asymmetric
rostral maxillary eminences at the rostrum base, this bulge displays various degrees of elevation in different specimens, which may be interpreted as sexual dimorphism. Specimens of I. piscatus n. gen., n. sp. bear two sets of even crests: spur-like rostral maxillary crests and longitudinal maxillary crests laterally bordering a wide and long facial basin. A preliminary macroscopic observation of these elements indicates very dense bones, with a compactness comparable with that of cetacean ear bones. Questioning their function, the high medial rostral elements (the premaxillary spheroid of G. hiberus n. gen., n. sp. and the medial bulge of T. atlanticus n. sp.) remind the huge rostral maxillary crests of adult males of the extant Hyperoodon ampullatus (Forster, 1770). In the latter, the crests are very likely related to head-butting. However, they are made of much more spongy bone than in the fossil taxa studied here, and therefore possibly better mechanically suited for facing impacts. Other interpretations of these unusual bone specializations, related to deep-diving (ballast) and echolocation (sound reflection), fail to explain the diversity of shapes and the hypothetical sexual dimorphism observed in at least part of the taxa. e spur-like rostral maxillary crests and long maxillary crests limiting the large facial basin in I. piscatus n. gen., n. sp. and the excrescences on the maxilla at the rostrum base in Choneziphius spp. are instead interpreted as areas of origin for rostral and facial muscles, acting on the nasal passages, blowhole, and melon. From a palaeobiogeographic point of view, the newly described taxa further emphasize the differences in the North Atlantic (including Iberian Peninsula) and South African Neogene ziphiid faunal lists. Even if the stratigraphic context is poorly understood, leaving open the question of the geological age for most of the dredged specimens, these differences in the composition of cold to temperate northern and southern hemisphere fossil ziphiid faunas may be explained by a warm-water equatorial barrier.

Mateus, O, Tschopp E.  2013.  Cathetosaurus as a valid sauropod genus and comparisons with Camarasaurus. Journal of Vertebrate Paleontology, Program and Abstracts, 2013. :173.mateus__tschopp_2013_cathetosaurs_camarasaurus__svp_meeting_abstracts_213.pdf
Schulp, AS, Polcyn MJ, Mateus O, Jacobs LL.  2013.  Two rare mosasaurs from the Maastrichtian of Angola and the Netherlands. Netherlands Journal of Geosciences — Geologie en Mijnbouw. 92(1):3-10. Abstractschulp_et_al_2013_two_rare_mosasaurs_from_the_maastrichtian_of_angola__njg-92-1-schulp.pdf

We report here the addition of two rare mosasaur taxa to the Maastrichtian marine amniote fauna of Angola. The new specimens include a dentary fragment referable to the large carnivore Prognathodon saturator and an isolated tooth of the small durophage Carinodens belgicus. Both were recovered from Maastrichtian outcrops in southern Angola in 2011. Additionally, a complete posterior mandibular unit of a large mosasaur from the type Maastrichtian of The Netherlands, collected some time prior to 1879 and previously identified as ‘Mosasaurus giganteus’, is described and reassigned here to Prognathodon saturator; historical issues surrounding the taxonomic attribution of this specimen are clarified. The new material extends the known geographic distribution of Prognathodon saturator and Carinodens belgicus.

Araújo, R, Castanhinha R, Martins RMS, Mateus O, Hendrickx C, Beckmann F, Schell N, Alves LC.  2013.  Filling the gaps of dinosaur eggshell phylogeny: Late Jurassic Theropod clutch with embryos from Portugal, may. Scientific Reports. 3: Nature Publishing Group AbstractWebsite
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Mannion, PD, Upchurch P, Barnes RN, Mateus O.  2013.  Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society. 168:98-206., Number 1 Abstract
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Tschopp, E, Mateus O.  2013.  The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs. Journal of Systematic Palaeontology. 11(7):853–888. Abstracttschopp__mateus_2013_the_skull_and_neck_of_a_new_flagellicaudatan_sauropod_from_the_morrison.pdfWebsite

A new taxon of diplodocid sauropod, Kaatedocus siberi gen. et sp. nov., is recognized based on well-preserved cervical vertebrae and skull from the Morrison Formation (Kimmeridgian, Late Jurassic) of northern Wyoming, USA. A phylogenetic analysis places it inside Diplodocinae (Sauropoda: Flagellicaudata: Diplodocidae), as a sister taxon to a clade uniting Tornieria africana and the classical diplodocines Barosaurus lentus and Diplodocus. The taxon is diagnosed by a unique combination of plesiomorphic and derived traits, as well as the following unambiguous autapomorphies within Diplodocidae: frontals separated anteriorly by a U-shaped notch; squamosals restricted to the post-orbital region; presence of a postparietal foramen; a narrow, sharp and distinct sagittal nuchal crest; the paired basal tuber with a straight anterior edge in ventral view; anterior end of the prezygapophyses of mid- and posterior cervical vertebrae is often an anterior extension of the pre-epipophysis, which projects considerably anterior to the articular facet; anterodorsal corner of the lateral side of the posterior cervical vertebrae marked by a rugose tuberosity; posterior margin of the prezygapophyseal articular facet of posterior cervical vertebrae bordered posteriorly by conspicuous transverse sulcus; posterior cervical neural spines parallel to converging. The inclusion of K. siberi and several newly described characters into a previously published phylogenetic analysis recovers the new taxon as basal diplodocine, which concurs well with the low stratigraphical position of the holotype specimen. Dinheirosaurus and Supersaurus now represent the sister clade to Apatosaurus and Diplodocinae and therefore the most basal diplodocid genera. The geographical location in the less known northern parts of the Morrison Fm., where K. siberi was found, corroborates previous hypotheses on faunal provinces within the formation. The probable subadult ontogenetic stage of the holotype specimen allows analysis of ontogenetic changes and their influence on diplodocid phylogeny.