Multigene Molecular Systematics Confirm Species Status of Morphologically Convergent Pagurus Hermit Crabs

Introduction: In spite of contemporary morphological taxonomy appraisals, apparent high morphological similarity raises uncertainty about the species status of certain Pagurus hermit crabs. This is exemplified between two European species, Pagurus excavatus (Herbst, 1791) and Pagurus alatus (Fabricius 1775), whose species status is still difficult to resolve using morphological criteria alone. Methodology/Principal Findings: To address such ambiguities, we used combinations of Maximum Likelihood (ML) and Bayesian Inference (BI) methods to delineate species boundaries of P. alatus and P. excavatus and formulate an intermediate Pagurus phylogenetic hypothesis, based upon single and concatenated mitochondrial (cytochrome oxidase I [COI]) and nuclear (16S and 28s ribosomal RNA) gene partitions. The molecular data supported the species status of P. excavatus and P. alatus and also clearly resolved two divergent clades within hermit crabs from the Northeast Atlantic Ocean and the Mediterranean Sea. Conclusions/Significance: Despite the abundance and prominent ecological role of hermit crabs, Pagurus, in North East Atlantic Ocean and Mediterranean Sea ecosystems, many important aspects of their taxonomy, biology, systematics and evolution remain poorly explored. The topologies presented here should be regarded as hypotheses that can be incorporated into the robust and integrated understanding of the systematic relationships within and between species of the genus Pagurus inhabiting the Northeast Atlantic Ocean and the Mediterranean Sea

Animal Behavior Frozen in Time: Gregarious Behavior of Early Jurassic Lobsters within an Ammonoid Body Chamber

Direct animal behavior can be inferred from the fossil record only in exceptional circumstances. The exceptional mode of preservation of ammonoid shells in the Posidonia Shale (Lower Jurassic, lower Toarcian) of Dotternhausen in southern Germany, with only the organic periostracum preserved, provides an excellent opportunity to observe the contents of the ammonoid body chamber because this periostracum is translucent. Here, we report upon three delicate lobsters preserved within a compressed ammonoid specimen of Harpoceras falciferum. We attempt to explain this gregarious behavior. The three lobsters were studied using standard microscopy under low angle light. The lobsters belong to the extinct family of the Eryonidae; further identification was not possible. The organic material of the three small lobsters is preserved more than halfway into the ammonoid body chamber. The lobsters are closely spaced and are positioned with their tails oriented toward each other. The specimens are interpreted to represent corpses rather than molts. The lobsters probably sought shelter in preparation for molting or against predators such as fish that were present in Dotternhausen. Alternatively, the soft tissue of the ammonoid may have been a source of food that attracted the lobsters, or it may have served as a long-term residency for the lobsters (inquilinism). The lobsters represent the oldest known example of gregariousness amongst lobsters and decapods in the fossil record. Gregarious behavior in lobsters, also known for extant lobsters, thus developed earlier in earth's history than previously known. Moreover, this is one of the oldest known examples of decapod crustaceans preserved within cephalopod shells

The trace fossil Lepidenteron lewesiensis: a taphonomic window on diversity of Late Cretaceous fishes

The trace fossil Lepidenteron lewesiensis (Mantell 1822) provides an exceptional taphonomic window to diversity of fishes as shown for the Upper Cretaceous of Poland, in the Middle Turonian–Lower Maastrichtian deposits of the Opole Trough, Miechów Trough, Mazury-Podlasie Homocline, and SE part of the Border Synclinorium. Lepidenteron lewesiensis is an unbranched burrow lined with small fish scales and bones, without a constructed wall. It contains scales, vertebrae, and bones of the head belonging to ten taxa of teleostean fishes: two undetermined teleosteans, six undetermined Clupeocephala, one Dercetidae, and one undetermined euteleostean. The preservation of fish remains suggests that fishes were pulled down into the burrow by an animal, probably by eunicid polychaetes.Das Spurenfossil Lepidenteron lewesiensis (Mantell 1822) ermöglicht einen biostratinomischen Einblick in die Diversität von Fischen, wie Fossilmaterial aus der Oberkreide von Polen zeigt. Es stammt aus dem Mittelturonium bis Untermaastrichtium des südöstlichen Abschnittes der Grenz-Synklinale, dem Opolen-Trog, dem Miechów-Trog und der Masuren-Podlachien-Homoklinale. L. lewesiensis ist ein unverzweigter Grabgang ohne ausgekleidete Wände, dessen Ränder von kleinen Fischschuppen und—knochen gebildet werden. Diese setzen sich aus Schuppen, Wirbel und Schädelknochen von zehn Teleostei-Taxa zusammen und zwar aus zwei unbestimmte Teleosteer, sechs unbestimmten Clupeocephala, einem Dercetidae und einem unbestimmten Euteleostei. Die Erhaltung der Fischüberreste deutet darauf hin, dass die Fische von einem Tier, wahrscheinlich einem Polychaeten der Familie Eunicidae, in den Bau gezogen wurden.We are very grateful to Dr. Lionel Cavin (Geneva) and the anonymous reviewer for constructive comments on an earlier version of the manuscript. Additional support was provided by the Jagiellonian University (DS funds), National Science Center (Grant Number: PRO-2011/01/N/ST10/07717), and the Laboratory of Geology (University of Lodz) BSt Grant No. 560/844. We are grateful to Dr. Johann Egger (Wien) and Kilian Eichenseer M.Sc. (Erlangen) for help with translating the abstract into German. We are grateful to Dr. Ursula Göhlich (Wien) for access to the Dercetis specimen

Acanthoscaphites varians (Lopuski, 1911) (Ammonoidea) from the Upper Maastrichtian of Haccourt, NE Belgium

A specimen of the Scaphitid ammonite Acanthoscaphites varians (Lopuski, 1911) is described from the late Maastrichtian Vijlen Member of the Gulpen Formation as exposed in the SA Ciments Portland Liegeois quarry at Haccourt, Liege, NE Belgium. This record constitutes an important addition to the ammonite fauna of the Maastrichtian type area. -Author

First record of Pachydiscus noetlingi Kennedy, 1999 (Ammonoidea) from the Maastrichtian type area (the Netherlands)

Two specimens of a pachydiscid ammonite, a fragmentary silicified phragmocone from the Kunrade Limestone facies at Kunrade (Schunck), and a partial external mould preserved in flint from the Nekum Member (both Maastricht Formation, Belemnitella junior Zone of authors) at the former Blom quarry (Berg en Terblijt), are identified as Pachydiscus (P.) noetlingi Kennedy, 1999, a species previously known only from the Upper Maastrichtian of Baluchistan (Pakistan). This new record underscores the proposal of incursions of Tethyan biota into the type area of the Maastrichtian Stage, previously documented for other groups, including echinoderms and bivalves, as well

Additional late Cretaceous ammonite records from the Maastrichtian type area

Early 20th century subsurface collections from mine shafts in northeast Belgium and adjacent parts of the Netherlands and recent outcrop collections include ammonite assemblages of early Campanian of latest Maastrichtian age. In the present paper additional material of the pachydiscids Eupachydiscus levyi (De Grossouvre, 1894), Pachydiscus (P.) launayi De Grossouvre, 1894 and P. (P.) colligatus (Binkhorst, 1861) and the scaphitids Scaphites (S.) gibbus Schluter, 1872 and Trachyscaphites s. spiniger (Schluter, 1872) is described. Ammonites not recorded previously from the area include Hauericeras (Gardeniceras) cf. rembda (Forbes, 1846), Pachydiscus (P.) haldemsis (Schluter, 1867), Patagiosites sp., Neancyloceras? phaleratum (Griepenkerl, 1889), Trachybaculites columna (Morton, 1834) and Hoploscaphites sp. nov. The diplomoceratidM Glyptoxoceras rugatum (Forbes, 1846), well known fromthe upper Maastricht Formation and Kunradfe Limestone facies of that unit, is recorded from the Vijlen Member (Gulpen Formation, early Late Maastrichtian) for the first time

Acanthoscaphites tridens (Kner, 1848) (Ammonoidea) from the Vijlen Member (Lower Maastrichtian) of Gulpen, Limburg, The Netherlands

A specimen of the scaphitid ammonite Acanthoscaphites tridens was collected in situ from the lower part of the Vijlen Member, southwest of Gulpen. This species has been widely quoted as an index for the lowest ammonite zone of the Maastrichtian Stage, but its precise age was poorly known. Associated nannofossils show the Gulpen specimen to come from nannofossil zone CC 24. A calibration of nannofossil and belemnite zones indicates it to be no older than the Belemnella occidentalis Zone, which is well above the base of the Maastrichtian Stage. The Gulpen specimen is thus younger than the type occurrence in the Ukraine which is in nannofossil subzone CC 23B, equivalent to the upper part of the Belemnella lanceolata Zone. -from Author

Giant scaphitid ammonites from the Maastrichtian of Europe

Giant scaphitid ammonites from the Maastrichtian of Europe have generally been assigned to Acanthoscaphites NOWAK, 1911. Prior to the present study, this genus comprised five species: A. tridens (KNER, 1848), A. varians (LOPUSKI, 1911), A. verneuilianus (D'ORBIGNY, 1841), A. sp. of KENNEDY (1987) and A. sp. of KENNEDY and CHRISTENSEN (1997). Of the first-named taxon, material from Aachen-Schneeberg of Early Maastrichtian age, including the specimen illustrated by HOLZAPFEL (1887-89) long thought to have been lost, is described. Recently collected topotype material from Kazimierz Dolny, and from Rejowiec (Poland), of latest Maastrichtian age (Belemnella kazimiroviensis Zone), allows A. varians to be revised. Specimens from the late Early and early Late Maastrichtian of NW Europe, assigned to A. varians, differ consistently in details of ornament, and are assigned to a new subspecies, A. v. blaszkiewiczi n. subsp. Style of ribbing and tuberculation of the varians stock differs from that of A. tridens to such an extent that a new subgenus, Euroscaphites n. subgen., is erected, with varians as type species. The Late Maastrichtian 'Acanthoscaphites' verneuilianus, only known from phragmocones, is provisionally assigned to the new subgenus. The other two species previously reffered to Acanthoscaphites, viz. A. sp. of KENNEDY (1987) and A. sp. of KENNEDY and CHRISTENSEN (1997), both of Late Maastrichtian age, cannot be assigned confidently to either subgenus

Giant scaphitid ammonites from the Maastrichtian of Europe

Giant scaphitid ammonites from the Maastrichtian of Europe have generally been assigned to Acanthoscaphites NOWAK, 1911. Prior to the present study, this genus comprised five species: A. tridens (KNER, 1848), A. varians (LOPUSKI, 1911), A. verneuilianus (D'ORBIGNY, 1841), A. sp. of KENNEDY (1987) and A. sp. of KENNEDY and CHRISTENSEN (1997). Of the first-named taxon, material from Aachen-Schneeberg of Early Maastrichtian age, including the specimen illustrated by HOLZAPFEL (1887-89) long thought to have been lost, is described. Recently collected topotype material from Kazimierz Dolny, and from Rejowiec (Poland), of latest Maastrichtian age (Belemnella kazimiroviensis Zone), allows A. varians to be revised. Specimens from the late Early and early Late Maastrichtian of NW Europe, assigned to A. varians, differ consistently in details of ornament, and are assigned to a new subspecies, A. v. blaszkiewiczi n. subsp. Style of ribbing and tuberculation of the varians stock differs from that of A. tridens to such an extent that a new subgenus, Euroscaphites n. subgen., is erected, with varians as type species. The Late Maastrichtian 'Acanthoscaphites' verneuilianus, only known from phragmocones, is provisionally assigned to the new subgenus. The other two species previously reffered to Acanthoscaphites, viz. A. sp. of KENNEDY (1987) and A. sp. of KENNEDY and CHRISTENSEN (1997), both of Late Maastrichtian age, cannot be assigned confidently to either subgenus

Campanian ammonites and nannofossils from southern Limburg, the Netherlands

New records of ammonites and nannofossil assemblages from the Vaals Formation northeast of Cottessen and at Raren close to the Netherlands/Belgium border include Pachydiscus (Pachydiscus) subrobustus Seunes, 1892, Hoplitoplacenticeras (Hoplitoplacenticeras) marroti (Coquand, 1859) and Scaphites (Scaphites) hippocrepis (DeKay, 1828) III sensu Cobban, 1969, while the Zeven Wegen Member (Gulpen Formation) at Zeven Wegen (Vijlenerbosch) yields Scaphites (Scaphites) gibbus Schluter, 1872, the Cottessen and Zeven Wegen ammonite horizons being referred to nannofossil zone CC/B 20 of the Boreal scheme. -Author