
Dirk BrandisKiel University | CAU · Zoological Museum
Dirk Brandis
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Introduction
Publications
Publications (74)
Das Zoologische Museum in Kiel, eine der ältesten naturkundlichen Sammlungen Deutschlands, bewahrt bedeutende wissenschaftliche Sammlungen, darunter die Austernsammlung von Karl August Möbius. Diese Sammlung entstand im 19. Jahrhundert im Rahmen von Möbius' umfassenden Studien zur Ökologie und Biologie von Austernbänken, die er auf Anweisung der pr...
The Aegean region is biogeographically complex for freshwater crabs of the genus Potamon Savigny, 1816. Especially Potamon kretaion Giavarini, 1943 has a remarkably different distribution pattern compared to its congeners: With its exclusive occurrence on the island of Crete, it is the only Potamon species that is endemic to an Aegean island, and i...
Understanding the factors that predispose species and populations to decline and extinction is a major challenge of biodiversity research. In the present study, we investigated the historical population genomics of an extinct oyster population from the Wadden Sea collected between 1868 and 1888, and compared it to French and British populations sam...
Morphological species identification is the traditional way to identify species. More recently, biodiversity studies have depended on DNA barcoding for species identification. Mismatches between morphological and genetic species identification caused by voucher specimen misidentifications lead to ambiguous species identification. We used barnacles...
The patchy distribution of the ditch shrimp Palaemon varians (Palaemonidae) in small-scale habitats with low salinity may hint at isolation and fragmentation processes. In order to evaluate the extent to which gene flow barriers exist and salinity has an influence on this dispersal pattern, the genetic diversity and differentiation of Baltic and No...
Cryptic biological invasions are largely unrecognised, leading to an underestimation of the number of invading taxa and their potential impacts. The Chinese mitten crab, Eriocheir sinensis, is a highly invasive species with serious economic and ecological impacts in Europe. Recently, mitochondrial DNA (mtDNA) of the Japanese mitten crab, E. japonic...
Environmental gradients have emerged as important barriers to structuring populations and species distributions. We set out to test whether the strong salinity gradient from the marine North Sea to the brackish Baltic Sea in northern Europe represents an ecological and genetic break, and to identify life history traits that correlate with the stren...
Aim
Environmental gradients have emerged as important barriers structuring populations and species distributions. We set out to test whether a strong salinity gradient from marine to brackish, represented in a marginal northern European sea, should be considered a diversification hotspot or a population sink, and to identify life history traits tha...
Changing species assemblages represent major challenges to ecosystems around the world. Retracing these changes is limited by our knowledge of past biodiversity. Natural history collections represent archives of biodiversity and are therefore an unparalleled source to study biodiversity changes. In the present study, we tested the value of natural...
The historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea...
Abstract Since its introduction in the 1960’s for aquaculture, the Pacific oyster Magallana gigas (Thunberg, 1793) has successfully spread along almost all European coasts with far-reaching consequences for marine ecosystems. Up to now, it has not been recorded from the Baltic Sea proper. This was considered a consequence of the low salinity condit...
Genetic studies of introduced non-native species are a valuable tool to investigate invasion history and pathways, source populations and multiple introductions of alien species, as well as evolutionary genetic changes following establishment in a new environment. We used a set of nine polymorphic microsatellites to analyse the population genetic s...
The great auk was once abundant and distributed across the North Atlantic. It is now extinct, having been heavily exploited for its eggs, meat, and feathers. We investigated the impact of human hunting on its demise by integrating genetic data, GPS-based ocean current data, and analyses of population viability. We sequenced complete mitochondrial g...
Natural history collections are fundamental for biodiversity research as well as for any applied environment-related research. These collections can be seen as archives of earth´s life providing the basis to address highly relevant scientific questions such as how biodiversity changes in certain environments, either through evolutionary processes i...
The Chinese mitten crab ( Eriocheir sinensis ) is a prominent aquatic invader with substantial negative economic and environmental impacts. The aim of the present study was to re-evaluate the genetic diversity of mitten crabs throughout their native and invaded ranges based on publicly available sequence data, and assess if multiple introductions o...
We describe a new species of freshwater crab, Himalayapotamon robertsianum sp. nov. from Punjab province of Pakistan, based on morphological characters of the carapace and the first gonopod. The new species demarcates the westernmost distribution limit of the genus. Additionally, we analysed partial sequences of the 16S rRNA locus for some species...
Adult female Calappidae were examined with light microscopy and microcom-puted tomography for the presence of a pleon-holding mechanism. A typical press-button consisting of a protrusion on the fifth thoracic sternite and a socket on the sixth pleon segment was found in species of the genera Calappa, Calappula, Cycloes, Mursia, and Paracy-clois. Wi...
Life-history traits and interactions with native species play an important role for the successful estab- lishment of non-native species in new habitats. We investigated the recent successful invasion of the Pacific crabs Hemigrapsus takanoi and H. sanguineus to the southeastern North Sea coast with respect to their recruitment patterns, as well as...
Eubrachyurans not only exhibit a crab-like body shape, consisting of a mostly wide cephalothorax and a thin, shield-like pleon folded underneath it, but reportedly hold the pleon in this position with the use of specialized holding structures. To further our knowledge of the variability of these holding structures, and investigate their functionali...
Within the Brachyura there are a variety of specialized holding mechanisms, which facilitate the close attachment of the highly reduced pleon underneath the cephalothorax. The most common mechanism in eubrachyurans, known as the press-button, consists of a sternal protrusion and a corresponding pleonal socket. Reports on the microstructural propert...
Brachyuran crabs have a distinct outer morphology with a highly reduced pleon, which is folded underneath a usually broad cephalothorax. The pleon is secured in this position with a specialised holding mechanism, which consists of a sternal knob, or press-button, and, in most eubrachyurans, a corresponding pit or socket on the pleon. The effectiven...
A unique feature of the reproductive biology of the Eubrachyura is internal fertilization. Since the seminal receptacle - the sperm storage organ - is connected directly to the ovary, the mature oocytes would get fertilized within the seminal receptacle during ovulation. In contrast to that, primitve Brachyura have external fertilization due to the...
Male genitalia are extraordinarily diverse, and this diversity makes them valuable taxonomic and phylogenetic markers. Genitalia of true crabs (Brachyura) consist of two pairs of modified appendages, or gonopods. The first pair is tubular, and holds the second pair during copulation. Whether the second pair is shorter or longer than the first pair...
The reproductive system of the female Ethusa mascarone was studied with a combination of histological and MRI-techniques. The study reveals a completely new type of eubrachyuran seminal receptacle. This receptacle consists of two largely separate chambers that engage with each other in a manner similar to shaking hands. One chamber facing the media...
The pleon of eubrachyuran crabs is typically folded underneath the cephalothorax, inserted into a depression of the sternal plates, and secured in this position with specialized holding structures. Most prevalent is a press-button mechanism, which is present in juveniles of both sexes and adult males. The press-button consists of a protrusion on th...
In this study a new organization of the female reproductive organs of Eubrachyura is presented after using both histology and MRI and μCT analyses to investigate the morphology and function of the female reproductive organs of Dorippe sinica Chen, 1980. The reproductive organ is composed of two parts: an ectodermal sperm site and a mesodermal ovary...
True crabs (Brachyura) exhibit a very distinct outer morphology. In contrast to most other decapods, especially their pleon has undergone massive morphological changes. It is reduced to a thin shield, which is folded underneath the cephalothorax. Unlike other decapods with such a crab-like outer morphology, as for example the anomuran Porcellanidae...
Twenty years after its initial introduction to Europe, the Asian brush clawed crab Hemigrapsus takanoi is now a successful invader of the European Atlantic and North Sea coasts from northern Spain to southern Denmark. In July 2014, this species was recorded in the Baltic Sea for the first time, as eight individuals were found in the inner Kiel Fjor...
Male True Crabs use two pairs of gonopods to deliver mating products during copulation. Commonly, the second pair is shorter than the first pair, and most research to date has focused on species with short second gonopods. We investigated male and female copulatory organs in Calappula saussurei and Calappa pelii, two species of box crabs (Calappida...
In this article, the morphology and function of the female reproductive organs of Ebalia tumefacta were investigated using histological methods. While the vagina conforms to the concave type, the study reveals a new orientation of seminal receptacle compartments. The seminal receptacle consists of two chambers, which are oriented in anterior-poster...
Museum collections are a unique window onto the diversity of species on earth. However, detailed information on anatomical structures is currently difficult to come by since that mostly requires the destruction of the object of interest. Magnetic resonance imaging allows for non-invasive threedimensional imaging of soft tissue structures with high...
Male brachyurans have a pleon holding mechanism which secures the pleon when it is folded underneath the cephalothorax. The most prevalent holding mechanism is known as a typical press-button mechanism. It consists of a pretuberance on the sternite of the fifth segment of the cephalothorax and a corresponding socket on the sixth pleon segment (Guin...
AIM: We investigate the biogeographical history of the species-rich Sundaic freshwater crab genus Parathelphusa (family Gecarcinucidae). In particular, we ask to what extent eustatic sea-level fluctuations influenced diversification and species distribution. We test the prediction that sea-level fluctuations in the course of the Pleistocene glaciat...
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 pair...
Male copulatory system of Pinnotheridae
We investigated sperm cells and spermatophores of four species of Old World freshwater crabs belonging to three different genera of the subfamily Potaminae (family Potamidae). Characters previously believed to be apomorphic for the potamid subfamily Potamiscinae were also found to occur in the Potaminae. To infer the morphological ancestral charact...
Eriocheir sinensis invaded the Baltic Sea over 80 years ago, but there is still little known about mitten crab reproduction in this region. According to present knowledge, reproduction does not occur in the central, eastern and northern parts of the Baltic Sea due to the low salinity present. Sufficient salinity levels for reproduction of the Chine...
Commensal pea crabs inhabiting bivalves have a high reproductive output due to the extension and fecundity of the ovary. We studied the underlying morphology of the female reproductive system in the Pinnotheridae Pinnotheres pisum, Pinnotheres pectunculi and Nepinnotheres pinnotheres using light microscopy and transmission electron microscopy (TEM)...
The morphology of the reproductive organs of three species of fiddler crabs, Uca ecuadoriensis, Uca c.f. forcipata, and Uca tangeri were investigated to subsequently produce a model of their mode of operation. Vulva, vagina, and spermatheca in females, and the first and second gonopods in males were examined by applying histological techniques and...
The phylogeny of the Asian freshwater crabs of the family Gecarcinucidae is investigated using the
mitochondrial large subunit rRNA gene and the nuclear encoded histone 3 gene. The results confirm
the monophyly of the Gecarcinucidae. A division into two families, Gecarcinucidae and Parathelphusidae,
is not supported. Therefore, and in consideration...
We investigated the ultrastructure of spermatozoa and spermatophores of 19 palaeotropical freshwater crab species [12 species of the Gecarcinucidae, 6 of the Potamidae (Potamiscinae), and 1 species of the Potamonautidae (Deckeniinae: Hydrothelphusini)]. The investigated Potamiscinae have densely packed coenospermic spermatophores with the exception...
The current state of freshwater crab taxonomy argues for the freshwater crab family of the Gecarcinucidae to have its main species diversity in Southeast Asia. Despite its diversity, phylogenetic relationships and biogeographic history of this group remained poorly understood.
In the present study, we investigated the phylogeny of the gecarcinucid...
Phylogenetic relationships of gecarcinucoid freshwater crabs were investigated, based on morphology of the male second gonopod. In addition, a comparison of sequences from the mitochondrial large subunit rRNA gene helped to resolve the phylogeny of this group and relationships to other Old World freshwater crabs. As a result, we recognise two siste...
Taxonomic research on freshwater crabs dates back to the 18th century. Nevertheless, the systematics and the phylogenetic relationship among freshwater crabs still remain elusive. In consequence, there are only few biogeographic models explaining their present range.
In the Old World two superfamilies of freshwater crabs are recognised, the Potamoi...
The freshwater crab fauna of Nepal is revised on the basis of material, collected in January and February 2000. Species composition of the Nepalese crab fauna is reconsidered and families as well as genera are re-described. A key for all species dealt with is provided. The genus Paratclphusutla ALCOCK 1909 is revised and the genera Lobothelphusa BO...
Buch zur Artenvielfalt in Heidelberg. 2 erweiterte Auflage eines Tagungsbandes zu den Heidelberger Tagen der Artenvielfalt 2000, 2002 und 2004, die im Rahmen der.Geo-Tage der Artenvielfalt durchgeführt wurden. In diesem Buch werden der Ablauf der Veranstaltung, die Befunde einer Artenerhebung und allgemeine Beiträge zu folgenden Bereichen dargestel...
Spermatophore formation in Galathea intermedia begins in the proximal part of the vas deferens. The contents subsequently form a spermatophoric ribbon, the so-called "secondary spermatophore," in its distal part. A strongly muscular ductus ejaculatorius is present in the coxa of the fifth pereiopod which builds up pressure for the extrusion of the...
The mandibular palp of freshwater crabs is used for taxonomic studies since the early investigations of Alcock in 1910. Diagnostic character states of the mandibular palp are the number of segments (either two or three) and the morphology of the terminal segment (either bilobed or simple). Up to now, taxonomists have focused just on the outer morph...
The Himalayas are known to be a geologically young and dynamic mountain range hosting an endemic flora and fauna. To date, for freshwater crabs, one endemic subgenus within the genus Potamon, Potamon (Himalayapotamon) Pretzmann, 1966, has been described from the Himalayas. This subgenus includes two species, Potamon atkinsonianum (Wood-Mason, 1871)...
Tagungsband zum Heidelberger Tag der Artenvielfalt am 3.Juni 2000, der im Rahmen des 2.Geo-Tages der Artenvielfalt durchgeführt wurde. In diesem Buch werden der Ablauf der Veranstaltung, die Befunde einer Artenerhebung und allgemeine Beiträge zu folgenden Bereichen dargestellt: Kulturlandschaft und Lebensräume im Untersuchungsgebiet Heidelberg (2 B...
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...
The crayfish parasite 'Psorospermium haeckeli', which supposedly includes several species, is reported for the first time from the stone crayfish Austropotamobius torrentium. The infected specimens were from the Kammlach river in Bavaria (Germany), a place where A. torrentium and the noble crayfish Astacus astacus have coexisted for more than 20 yr...
The freshwater crab populations of the Khabur River in Syria exhibit a number of constant morphological characters distinguishing them from the other species within the Euphrates-Tigris system. A new species is erected under the name Potamon mesopotamicum to accommodate this very distinct form. Relations to other species of Potamon (Centropotamon)...
Recent investigations of Asian freshwater crabs of the superfamily Potamoidea Ortmann, 1896 use the Potamidae Ortmann, 1896 as the only valid family, although three families have been described from South-East Asia: the Potamidae Ortmann, 1896, the Isolapotamidae Bott, 1970 and the Sinopotamidae Bott, 1970. Crabs formerly included in the Isolapotam...