Michael Türkay

Morphology and function of the copulatory system in freshwater crabs of the genus Potamon

To understand the reproductive processes of freshwater crabs of the genus Potamon, we examined the first and second gonopod and the gonoducts of the female by histological methods. The gonopods are highly modified compared to those of other brachyuran crabs. In particular, the second gonopod is unusually long and has a special morphology, ending in a long sclerotized tube. Suggestions for the function of both gonopods and their different parts are presented. Tubulation of the first and second gonopod is observed. Rosette glands, which are abundant in the subterminal joint of the first gonopod, are connected to the sperm channel by cuticular pores. In females, the chitinous parts of the inner vulva may prove to have a more constant morphology than the external flexible structures. J. Morphol. 239:157–166, 1999.

A review of the collections of the infraorders Thalassinidea Latreille, 1831 and Callianassidea Dana, 1852 (Decapoda, Pleocyemata) lodged in three German Museums, with revised keys to the genera and species

The collections of the infraorders Thalassinidea Latreille, 1831 and Callianassidea Dana, 1852 logded in three German Museums, viz., Zoologische Staatssammlung, Munich (ZSM), Zoologisches Museum der Universitat Hamburg, Hamburg (ZMH), and Museum fur Naturkunde, Berlin (ZMB) were examined. The results of the present study indicate that the material of these collections comprises 10 families, 31 genera, including one new genus, and 73 species, three of which are new to science.

The megaepifauna of the Dogger Bank (North Sea): species composition and faunal characteristics 1991–2008

During a long-term study in the summer months of the years 1991–2008, 176 megaepifaunal species were recorded through a series of beam trawl surveys on a grid of fixed stations on the Dogger Bank (central North Sea). This paper gives a qualitative overview on species composition throughout the research period, determined from samples collected during 15 cruises. In recent years, a number of species with more oceanic distribution patterns (e.g. species from SW British coasts) has been collected. In spite of these newcomers, there was a slight decrease in total species numbers during the research period.

Gastric teeth of some thoracotreme crabs and their contribution to the brachyuran phylogeny.

The gastric teeth of three ocypodoid species were investigated using scanning electron microscopy, and the morphological results were discussed with respect to the known food preferences. The species were chosen in particular because of contrasting ideas about their relationships within the Thoracotremata. For the genera Heloecius, Dotilla, Mictyris, and “Uca” (s. str.), we find a specific correlation of the gastric teeth with the suspension feeding. The lateral gastric teeth of Uca have no prominent lateral teeth cusps, and most of their teeth surface consists of transverse comb‐like lamellae. However, this possible food adaptation does not exclude the usability of specific teeth characters to distinguish species of suspension feeders. The closer relationship of the Dotillidae to grapsoid lines of gecarcinid or sesarmid crabs suggested by molecular data is not supported by the gastric teeth. For the genus Ucides, we found several characters that distinguish Ucides from the remaining ocypodoid genera Heloecius, Dotilla, Mictyris, and “Uca.” In particular, the structures of the lateral and the dorsomedian teeth show some similarities to genera of the Gecarcinidae and Sesarmidae. Our results suggest that foregut characters can be used for phylogenetic analyses. J. Morphol. 2011.

The male copulatory system of european pea crabs (crustacea, brachyura, pinnotheridae)

The male copulatory system of the European pinnotherid species Pinnotheres pisum, Pinnotheres pectunculi, and Nepinnotheres pinnotheres was investigated by gross morphology, scanning electron microscopy, histological methods, and confocal laser scanning microscopy. The brachyuran copulatory system is consistently formed by paired penes and two pairs of abdominal appendages, the gonopods, functioning in sperm transfer. In pinnotherids, the long first gonopods transfer the sperm mass into the female ducts. The first gonopod has the ejaculatory canal inside that opens both basally and distally. The second gonopod is solid, short, and conical. During copulation, the penis and the second gonopod are inserted into the basal lumen of the first gonopod. While the penis injects the sperm mass, the second gonopod functions in the transport of spermatozoa inside the ejaculatory canal toward its distal opening. The second gonopod is adapted for the sealing of the tubular system in the first gonopod by its specific shape and the ability to swell. Longitudinal cuticle foldings of the second gonopod hook into structures inside the first gonopod. The second gonopod can interact with the penis during copulation by a flexible flap separating the lumina in which the second gonopod and the penis are inserted. J. Morphol., 2012.

A COLLECTION OF THALASSINIDEA LATREILLE, 1831 (DECAPODA, PLEOCYEMATA) FROM THE SENCKENBERG FORSCHUNGSINSTITUT AND NATURAL HISTORY MUSEUM, FRANKFURT AM MAIN

Unidentified Thalassinidea deposited in the Senckenberg Museum were examined. The collection here presented contains 25 species, including two new genera and five new species, i.e., Axiidae: Anomalaxius floridanus gen. nov., sp. nov.; Meticonaxiidae: Meteoraxius meteor gen. nov., sp. nov.; Callianassidae: Trypaea vilavelebita sp. nov., Callichirus santarosaensis sp. nov.; and Upogebiidae: Upogebia hertwecki sp. nov. The form Calastacus laevis De Saint Laurent, 1972 is recorded only for the second time and is fully described and illustrated from a complete specimen. New distribution data are available herein for all species treated.

A new species of the Macrophthalmus boscii-group (Decapoda: Brachyura: Macrophthalmidae) from the Persian Gulf with designation of a Neotype for M. boscii Audouin (1826)

A number of characters were overlooked in the original description of Macrophthamus boscii Audouin in Animaux invertébr 1(4):77–98, 1826, therefore this species is redescribed from material collected close to the type locality and, as the type series is no longer extant, a Neotype is designated. M. sinuspersici sp. nov. is described from the Persian Gulf and distinguished from M. boscii in possessing a distinct stridulating ridge on the upper surface of the merus of the male cheliped (vs fully lacking in M. boscii) and by first male gonopod which has apical process inclined mesio-laterally, strongly emarginated (vs a remarkable plate-shaped apical process in M. boscii).

Cross-realm assessment of climate change impacts on species’ abundance trends

Climate change, land-use change, pollution and exploitation are among the main drivers of species’ population trends; however, their relative importance is much debated. We used a unique collection of over 1,000 local population time series in 22 communities across terrestrial, freshwater and marine realms within central Europe to compare the impacts of long-term temperature change and other environmental drivers from 1980 onwards. To disentangle different drivers, we related species’ population trends to species- and driver-specific attributes, such as temperature and habitat preference or pollution tolerance. We found a consistent impact of temperature change on the local abundances of terrestrial species. Populations of warm-dwelling species increased more than those of cold-dwelling species. In contrast, impacts of temperature change on aquatic species’ abundances were variable. Effects of temperature preference were more consistent in terrestrial communities than effects of habitat preference, suggesting that the impacts of temperature change have become widespread for recent changes in abundance within many terrestrial communities of central Europe.

The genera Atergatis , Microcassiope , Monodaeus , Paractea , Paragalene , and Xantho (Decapoda, Xanthidae) in the Mediterranean Sea

[A review of the relevant literature and a comparative study of adequate samples from the Mediterranean Sea and the Atlantic Ocean, revealed new key morphological features that facilitate a distinction of the Mediterranean species of Xanthidae. Based on this study, the Mediterranean Xantho granulicarpus Forest, 1953 is clearly distinguished from the Atlantic Xantho hydrophilus (Herbst, 1790) and Monodaeus guinotae Forest, 1976 is identical with Monodaeus couchii (Couch, 1851). For the species studied, additional information is given about their geographical distribution, as well as an identification key based on selected, constant features. Literaturstudien und vergleichende Untersuchungen geeigneter Proben aus dem Mittelmeer und dem Atlantischen Ozean haben neuen morphologische Schlusselmerkmale erbrqacht, die eine Unterscheidung der aus dem Mittelmeer stmmenden Arten der Xanthidae erleichtern. Als Ergebnis dieser Untersuchungen kann gesagt werden, dass Xantho granulicarpus Forest, 1953 aus dem Mittelmeer klar von Xantho hydrophilus (Herbst, 1790) aus dem Atlantik unterschieden ist und dass Monodaeus guinotae Forest, 1976 identisch mit Monodaeus couchii (Couch, 1851) ist. Fur die untersuchten Arten werden zusatzliche Verbreitungsangaben gemacht und ein Bestimmungsschlussel auf der Grundlage ausgewahlter konstanter Merkmale bereitgestellt. , A review of the relevant literature and a comparative study of adequate samples from the Mediterranean Sea and the Atlantic Ocean, revealed new key morphological features that facilitate a distinction of the Mediterranean species of Xanthidae. Based on this study, the Mediterranean Xantho granulicarpus Forest, 1953 is clearly distinguished from the Atlantic Xantho hydrophilus (Herbst, 1790) and Monodaeus guinotae Forest, 1976 is identical with Monodaeus couchii (Couch, 1851). For the species studied, additional information is given about their geographical distribution, as well as an identification key based on selected, constant features. Literaturstudien und vergleichende Untersuchungen geeigneter Proben aus dem Mittelmeer und dem Atlantischen Ozean haben neuen morphologische Schlusselmerkmale erbrqacht, die eine Unterscheidung der aus dem Mittelmeer stmmenden Arten der Xanthidae erleichtern. Als Ergebnis dieser Untersuchungen kann gesagt werden, dass Xantho granulicarpus Forest, 1953 aus dem Mittelmeer klar von Xantho hydrophilus (Herbst, 1790) aus dem Atlantik unterschieden ist und dass Monodaeus guinotae Forest, 1976 identisch mit Monodaeus couchii (Couch, 1851) ist. Fur die untersuchten Arten werden zusatzliche Verbreitungsangaben gemacht und ein Bestimmungsschlussel auf der Grundlage ausgewahlter konstanter Merkmale bereitgestellt. ]

Decapod fauna of the Helgoland trench (Crustacea) a long-term study in a biodiversity hotspot

Thirty-seven species of decapod Crustaceans were collected from the Helgoland Trench during a long-term study through the periods 1982-1992 and 2000-2013. This brings up the decapod species known from that area up to 41 (+ 3 uncertain ones). Most of the species have a boreal to temperate distribution pattern. The diversity and specificity of the fauna are particularly high and amount to about a quarter of the total species numbers of the German Bight. The Helgoland Trench can thus be considered as a biodiversity hotspot in the German Bight. Furthermore, the species composition reacts quite sensibly to temperature changes induced by climate change and alien species remained notably absent.