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Niebuhr, B. and Jagt, J.W.M. 2016. Revision of Hamites wernickeiWollemann, 1902 (Cephalopoda, Ancyloceratina) from the classic Lüneburg section (Upper Cretaceous, northern Germany). Acta Geologica Polonica, 66 (4), 627-644. Warszawa. A re-examination of heteromorph ammonites of late Campanian age from the Zeltberg section at Lüneburg has demonstrated that the type series of Hamites wernickei in fact comprises two different species that are here assigned to the nostoceratid Nostoceras Hyatt, 1894 and the polyptychoceratid Oxybeloceras Hyatt, 1900. Nostoceras (Didymoceras) wernickei (Wollemann, 1902) comb. nov., to which three of the four specimens that were described and illustrated by Wollemann (1902) belong, has irregularities of ribbing and tuberculation and changes its direction of growth at the transition from the helicoidal whorls to the hook, which is a typical feature of members of the subfamily Nostoceratinae. Torsion of body chambers is not developed in hairpin-shaped ammonite species, which means that the species name wernickei is no longer available for such polyptychoceratine diplomoceratids. Consequently, the fourth specimen figured and assigned to Hamites wernickei by Wollemann (1902) is here transferred to Oxybeloceras and considered conspecific to material from the Hannover area (Lehrte West Syncline) as O. aff. crassum (Whitfield, 1877). In addition to the "Heteroceras-Schicht des Mucronaten-Senons" of Lüneburg (bipunctatum/roemeri Zone, upper upper Campanian), the geographic range of N. (D.) wernickei probably includes Upper Austria, Tunisia and the Donbass region, while O. aff. crassum is known from the Hannover area (northern Germany), southern France, northern Spain and Upper Austria. [ABSTRACT FROM AUTHOR]

Extinct anomurans are known mostly by their carapaces. Regions in the fossil carapace are well delimited by grooves and, by comparison with extant hermit crabs, they can be referred to the underlying internal organs. In this paper we examine the allometric effects in ontogeny of two Jurassic hermit crabs of an extinct genusGastrodorus:G. neuhausensisvon Meyer, 1864 andG. bzowiensissp. nov. described herein. Both species occur in Oxfordian and Kimmeridgian strata in southern Poland, but the former species only in southern Germany. Samples of carapaces of both species consisted of carapaces of a wide size range, illustrative of the various ontogenetic stages. A reduced major axis was applied for assessment of allometry. The most pronounced positive allometric effect in both species concerned the posteriormost region of the cephalothoracic shield, which became disproportionally more elongated than the overall carapace length (positive allometry) as overall size increased. Statistically significant differences between the two species concern the cardiac region, which gained in length with size inG. neuhausensis(positive allometry) and became proportionally narrower in the new species (negative allometry). Thus it may be assumed that overall growth rate of the heart region was less in the latter species. Additionally, new terminology of carapace regions previously introduced to pagurids and based on morphology of recent representatives is applied to the gastrodorids. http://zoobank.org/urn:lsid:zoobank.org:pub:E64D2515-BD0D-4A78-83A7-D35C5F9FA3E5 [ABSTRACT FROM AUTHOR]

Associations of crustaceans with echinoids (Echinodermata) and bivalves (Mollusca) are not uncommon in modern oceans. Here we record the occurrence of anomurans, brachyurans and isopods within echinoid tests and bivalve shells from the Middle Jurassic of France, the Upper Jurassic of the Czech Republic, the Eocene of Croatia and the Miocene of Austria. Additionally a new genus and species of fossil cirolanid isopod from the Middle Jurassic of France is described. The present examples are interpreted as crustacean sheltering, probably for safe and undisturbed moulting (ecdysis), within a vacant host test or shell. However, accidental association (washed in) or even food remains cannot be ruled out entirely. [ABSTRACT FROM AUTHOR]

On the basis of carapaces, three new genera and species of symmetrical paguroid anomurans are described. Diogenicheles theodorae, Masticacheles longirostris,a n d Pilgrimcheles karolinae constitute the oldest known members of the family Parapylochelidae. As noted previously, assemblages fromsponge-reefal strata of Oxfordian (Late Jurassic) age in the southern Polish Uplands document an important radiation event amongst paguroids. Compared to the present day, the Parapylochelidae were more diverse during the mid-Mesozoic; they appear to have withdrawn from shallow, reefal waters to deep-water settings from the Late Jurassic onwards. Paguroid faunas from the Oxfordian of Europe already are highly diverse, both morphologically and phylogenetically, and comprise early members of the families Diogenidae, Pylochelidae, and Parapylochelidae. This suggests that the evolutionary history of paguroids started much earlier (i.e., in pre-Jurassic times) than previously assumed. New terms for several typical paguroid carapace regions are introduced and on the basis of carapace morphology and ecological shifts hypotheses on the early speciation of hermit crabs are put forward. [ABSTRACT FROM AUTHOR]

For a long time, the genus Knebelia Van Straelen, 1922 has comprised two species of eryonid lobster, K. bilobata ( Münster, 1839) and K. schuberti ( Meyer, 1836), both recorded exclusively from Late Jurassic Lagerstätten in southern Germany. Recently, the latter has been suggested to represent a juvenile individual of Cycleryon propinquus ( Schlotheim, 1822). A re-examination of the type and new material has led to our rejection of that interpretation and confirmation of assignment of this species to Knebelia. Two specimens, both possessing short frontal lobes, from plattenkalks at Nusplingen (late Kimmeridgian) and at Solnhofen (early Tithonian), respectively, are here assigned to a new species, K. totoroi sp. nov. This new species and a review of K. bilobata have furnished new insights into the origin and function of the frontal lobes, which are expansions articulated to the front of the carapace. They probably functioned as rudders facilitating 'tail-flip swimming' as observed in the paddle-like antennae of extant scyllarids ( Eucrustacea, Decapoda, Scyllaridae). The rudder-like lobes identified in Knebelia may therefore represent a case of convergent evolution. [ABSTRACT FROM AUTHOR]

The heteromorph ammonite Pravitoceras sigmoidale from the Upper Cretaceous Seidan Formation ( Izumi Group) in south-west Japan is frequently encrusted by sessile anomiid bivalves. Fossils of P. sigmoidale with anomiids are often concentrated at the top of or just above turbidite sandstones. Projecting retroversal hooks and apertures of P. sigmoidale are usually intact, and some individuals are associated with jaw apparatuses near apertures. Anomiids are found on both sides and ventral peripheries of P. sigmoidale conchs, attached predominantly to body chambers. These modes of occurrence suggest that the encrustation by anomiids occurred not on post-mortem floating or sunken carcasses but on live conchs and that these organisms were rapidly buried by turbidity current deposits shortly after death. Attachment to both flanks and ventral peripheries of the retroversal hooks may indicate that at least adult individuals of P. sigmoidale did not lie on the sea floor and did not drag their body chambers. It is suggested that fully mature individuals of this ammonite species lived for a long period of time after having formed the retroversal hook because a few generations of anomiids have colonized a single body chamber. Such colonization by anomiids is also observed on Didymoceras awajiense, which is considered to be the closely related ancestral species of P. sigmoidale. This anomiid-heteromorph ammonite commensal relationship might continue to persist in descendants during the course of evolution of these heteromorph ammonites. [ABSTRACT FROM AUTHOR]

An otherwise well-preserved test of the holasteroid echinoidHemipneustes striatoradiatus(Leske) from the Emael Member, Maastricht Formation (Maastrichtian, Upper Cretaceous) of Belgium, is infested by encrusting bivalves and foraminiferans and the boringRogerellaisp. In this specimen,Rogerellapreferentially infested and modified the ambulacral pore pairs of the echinoid close to the apex. This was not a commensal association. The echinoid test shows no growth deformations in response to this invasion; pore pairs are locally strongly infested; and encrusting invertebrates testify to the long post-mortem residence time of the test on the sea floor. Rather, the pore pairs of the dead echinoid were crannies attractive to settling larvae of acrothoracian barnacles, the producers ofRogerella. [ABSTRACT FROM PUBLISHER]

Two tests of the holasteroid echinoidHemipneustes striatoradiatus(Leske) from the type area of the Maastrichtian Stage (Upper Cretaceous) bear a varied infestation of episkeletozoans (oysters, bryozoan colony, and serpulids), borings (probableCaulostrepsisisp.,Oichnus simplexBromley), surface abrasion (Gnathichnus? isp.), and pits (O. excavatusDonovan and Jagt). OnlyO. excavatusrepresents a premortem infestation. In one specimen, the four individual pits of this ichnospecies are each associated with a different ambulacrum and pore pairs that, in life, bore respiratory tube feet; the anterior ambulacrum, of different gross morphology, is not infested. In the second test, three out of four of the same ambulacra are infested, although there are alsoO. excavatusin the interambulacra. The association betweenO. excavatusand the ambulacra of the echinoid, and thus its tube feet, is open to several plausible explanations, but most likely provided some form of feeding or protective advantage to the pit-forming organism. [ABSTRACT FROM PUBLISHER]

Clusters of gastropod egg capsules, inferred to be of neritoids and attached to the inner shell wall of the ultimate whorl of a large volutid gastropod, are here recorded from the upper Nekum Member (Maastricht Formation; late Maastrichtian) of the ENCI-Heidelberg Cement Group quarry, St Pietersberg (Maastricht, southeast Netherlands). Because the aragonitic shell of the volutid has dissolved, the outlines of the egg capsules are now revealed on the steinkern of indurated biocalcarenite, having been subsequently overgrown by cheilostome bryozoan colonies and preserved as mould bioimmurations. This represents the first example of gastropod eggs preserved through bioimmuration, as well as the first record of gastropod eggs from the Cretaceous. [ABSTRACT FROM AUTHOR]

A complete uppermost Maastrichtian-Danian succession in the Sumbar River section, western Kopet Dagh (southwest Turkmenistan, Central Asia), constitutes one of the few instances in the world where the fossil record of the last ammonites can be directly positioned with respect to the iridium-rich, impact-related clay layer, which defines the Cretaceous-Paleo- gene (K-Pg) boundary. Two ammonite taxa, Baculites cf. vertebralis and Hoploscaphites constrictus johnjagti, range up to a level directly beneath the K-Pg boundary clay in the Sumbar River section. Thus, these two forms probably survived until the very end of the Maastrichtian in the western Kopet Dagh area. The terminal Maastrichtian ammonite records from the Sumbar River area represent the southeasternmost occurrences of these essentially Boreal taxa. [ABSTRACT FROM AUTHOR]

A new species of diogenid paguroid, Eopaguropsis nidiaquilae, the earliest known member of the family to date, is recorded from sponge-reefal strata of Oxfordian (Late Jurassic) age in the southern Polish Uplands. Morphological features of the carapace suggest that the family Diogenidae diverged from other paguroid lineages such as the Pylochelidae and Parapaguridae, long before the Oxfordian Stage (161.2-155.7 Ma). The typically deep, V-shaped cervical groove of diogenids most likely was the product of fusion of the branchiocardiac and cervical grooves of their predecessors. [ABSTRACT FROM AUTHOR]

Strata with cyanobacterial-sponge buildups of Middle to Late Oxfordian (Late Jurassic) age in the southern Polish Up- lands document the earliest known members of the Pylochelidae. Two new Late Jurassic species of "symmetrical" hermit crabs, Ammopylocheles robertboreki and Jurapylocheles iwonae, are described.A new term, the massetic region, is introduced to describe the equivalent in paguroids of the hepatic region in brachyuran carapaces, because in the former, this region does not reflect the position of the liver but rather an attachment zone of the mandibular muscles. [ABSTRACT FROM AUTHOR]

Copyright of Boletín de la Sociedad Geológica Mexicana is the property of Sociedad Geologica Mexicana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a study on the Neritimorph gastropod genus Otostoma Retzil. It discusses the paleontological description of the specie, its operculum and phylogenetic significance. The genus described as a fossil from a sub-tropical, near-shore deposits of the late Early and Late Cretaceous ages, and has become extinct during the Middle Eocene period. Its hemispherical shell and D-shaped inner lip suggests its placement in the Neritimorpha Golikov and Starobogatov description.

The concept of convergence, that is, how unrelated animals independently evolve similar morphological traits, is a fundamental aspect of evolution. Hitherto, the Mesozoic ichthyosaurs were regarded as the sole obligate marine reptiles that achieved a fully streamlined body and a semilunate tail fluke. However, analyses of vertebral centrum morphometrics and process orientation have revealed that a subsequent clade of secondarily aquatic reptiles, the mosasaurs (here exemplified by the advanced, mid-Maastrichtian mosasaurine Plotosaurus), had developed a deep, fusiform body and a probable pursuit-predatory behaviour by the time of their sudden extinction at the Cretaceous–Paleogene boundary. Stringent physical constraints and selection pressures, imposed by the surrounding water, probably were responsible for this spectacular example of large-scale evolutionary convergence. [ABSTRACT FROM AUTHOR]

Copyright of Crustaceana is the property of Brill Academic Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ichnogenusCunctichnusFürsich, Palmer and Goodyear, 1994 is monotypic, its type ichnospecies,C. probansFürsich, Palmer and Goodyear, 1994, having hitherto been described solely from the Upper Jurassic (Tithonian) of southern England and the Paris Basin.Cunctichnus probansis recorded herein from the type Maastrichtian (Upper Cretaceous) of the province of Liège, northeast Belgium, that is, about 75 million years younger than previous published records. This specimen differs from the holotype in having a Y-shaped branch. [ABSTRACT FROM AUTHOR]