590 Tiere (Zoologie)
Refine
Year of publication
- 2014 (180) (remove)
Document Type
- Part of Periodical (130)
- Article (45)
- Doctoral Thesis (3)
- Book (1)
- Review (1)
Language
- English (180) (remove)
Has Fulltext
- yes (180) (remove)
Is part of the Bibliography
- no (180)
Keywords
- taxonomy (21)
- new species (19)
- Coleoptera (7)
- distribution (7)
- morphology (6)
- Odonata (5)
- Taxonomy (5)
- Cape Verde Islands (4)
- checklist (4)
- key (4)
Thought to be monotypic for decades, the only species in the goosefish genus Lophiomus Gill, Lm. setigerus (Vahl), shows a wide range of morphological variation and is distributed widely in the Indo-West Pacific (IWP). In this study, datasets for two mitochondrial and two nuclear genes sequences obtained from samples of Lophiomus collected in different localities across the IWP were constructed and analyzed to explore the phylogeny and species diversity within the genus. Our integrated approach with multiline evidence unveiled an unanticipated richness of at least six delimited species of Lophiomus. Herein, based on materials already available from museums and new specimens obtained primarily through the Tropical Deep-Sea Benthos program surveying IWP benthic fauna, we formally describe three new species: Lm. immaculioralis sp. nov., Lm. nigriventris sp. nov., and Lm. carusoi sp. nov. Also, we resurrect Lm. laticeps stat. rev. from synonyms of Lm. setigerus. These species can be diagnosed by genetics, body coloration, patterns on the floor of the mouth, peritoneum pigmentation, morphometric measurements, and meristic counts of cranial spines, dorsal-fin spines, and pectoral-fin and pelvic-fin rays from each other and from Lm. setigerus. The species Lm. setigerus, as well as the genus Lophiomus, are re-described accordingly based on the new results. Amended identification keys to the four extant lophiid genera and to species of Lophiomus are also provided.
A consistent muscle activation strategy underlies crawling and swimming in Caenorhabditis elegans
(2014)
Although undulatory swimming is observed in many organisms, the neuromuscular basis for undulatory movement patterns is not well understood. To better understand the basis for the generation of these movement patterns, we studied muscle activity in the nematode Caenorhabditis elegans. Caenorhabditis elegans exhibits a range of locomotion patterns: in low viscosity fluids the undulation has a wavelength longer than the body and propagates rapidly, while in high viscosity fluids or on agar media the undulatory waves are shorter and slower. Theoretical treatment of observed behaviour has suggested a large change in force–posture relationships at different viscosities, but analysis of bend propagation suggests that short-range proprioceptive feedback is used to control and generate body bends. How muscles could be activated in a way consistent with both these results is unclear. We therefore combined automated worm tracking with calcium imaging to determine muscle activation strategy in a variety of external substrates. Remarkably, we observed that across locomotion patterns spanning a threefold change in wavelength, peak muscle activation occurs approximately 45° (1/8th of a cycle) ahead of peak midline curvature. Although the location of peak force is predicted to vary widely, the activation pattern is consistent with required force in a model incorporating putative length- and velocity-dependence of muscle strength. Furthermore, a linear combination of local curvature and velocity can match the pattern of activation. This suggests that proprioception can enable the worm to swim effectively while working within the limitations of muscle biomechanics and neural control.
Speolepta leptogaster (Winnertz, 1863) is frequently occurring in European subterranean environments. As for most cave animals, studies addressing non-anatomical aspects are sparse. Here we present the first molecular study on S. leptogaster. We investigated the demographic structure (i.e. COI locus) of 69 specimens from 36 underground populations in Hesse (Central German Uplands) to get first insights into the species’ dispersal ability.
In total, 14 haplotypes were revealed. Haplotype diversity was relatively high, whereas nucleotide diversity was low. Furthermore, a significant but low pattern of isolation-by-distance and (a) past population expansion event(s) were detected.
Our genetic results suggest a (good) active dispersal ability for Speolepta leptogaster. The occurrence of several surface records of adult specimens corroborates this hypothesis. We discuss the developmental stages of S. leptogaster in the context of the ecological classification system and regard the species as a eutroglophile. Evidence has been found to distinguish two larval types. A reconstructed life-cycle of the species is provided.
The Cueva del Azufre in Tabasco, Mexico, is a nutrient-rich cave and its inhabitants need to cope with high levels of dissolved hydrogen sulfide and extreme hypoxia. One of the successful colonizers of this cave is the poeciliid fish Poecilia mexicana, which has received considerable attention as a model organism to examine evolutionary adaptations to extreme environmental conditions. Nonetheless, basic ecological data on the endemic cave molly population are still missing; here we aim to provide data on population densities, size class compositions and use of different microhabitats. We found high overall densities in the cave and highest densities at the middle part of the cave with more than 200 individuals per square meter. These sites have lower H2S concentrations compared to the inner parts where most large sulfide sources are located, but they are annually exposed to a religious harvesting ceremony of local Zoque people called La Pesca. We found a marked shift in size/age compositions towards an overabundance of smaller, juvenile fish at those sites. We discuss these findings in relation to several environmental gradients within the cave (i.e., differences in toxicity and lighting conditions), but we also tentatively argue that the annual fish harvest during a religious ceremony (La Pesca) locally diminishes competition (and possibly, cannibalism by large adults), which is followed by a phase of overcompensation of fish densities.
Cryptochrome 1a, located in the UV/violet-sensitive cones in the avian retina, is discussed as receptor molecule for the magnetic compass of birds. Our previous immunohistochemical studies of chicken retinae with an antiserum that labelled only activated cryptochrome 1a had shown activation of cryptochrome 1a under 373 nm UV, 424 nm blue, 502 nm turquoise and 565 nm green light. Green light, however, does not allow the first step of photoreduction of oxidized cryptochromes to the semiquinone. As the chickens had been kept under ‘white’ light before, we suggested that there was a supply of the semiquinone present at the beginning of the exposure to green light, which could be further reduced and then re-oxidized. To test this hypothesis, we exposed chickens to various wavelengths (1) for 30 min after being kept in daylight, (2) for 30 min after a 30 min pre-exposure to total darkness, and (3) for 1 h after being kept in daylight. In the first case, we found activated cryptochrome 1a under UV, blue, turquoise and green light; in the second two cases we found activated cryptochrome 1a only under UV to turquoise light, where the complete redox cycle of cryptochrome can run, but not under green light. This observation is in agreement with the hypothesis that activated cryptochrome 1a is found as long as there is some of the semiquinone left, but not when the supply is depleted. It supports the idea that the crucial radical pair for magnetoreception is generated during re-oxidation.
Debate exists regarding the number of species of the moon jellyfish (genus Aurelia), a common member of the planktonic community of the coastal shelf seas around the world. Three Aurelia congeners (A. aurita, A. labiata and A. limbata) are currently considered to exist but recent genetic analyses suggested that this is an oversimplification. We analyzed the morphological characteristics of scyphistomae, morphological characteristics of ephyrae and differences in the time span of the strobilation process of Aurelia congeners from 17, 7 and 6 different source populations, respectively, of known species. Morphological characteristics of scyphistomae were similar among the 17 populations but those of ephyrae, such as the shape and form of lappets, were effective discriminators in the 6 cases examined. We recommend identifying species based on differences in 1) the morphological characteristics of scyphistomae and ephyrae (and not only medusae), 2) the genetics of individuals, and 3) the geographical occurrence of the population. This study adds to the growing body of knowledge on scyphozoan scyphistomae and ephyrae, stages of the metagenic life cycle of scyphozoans that have received relatively little study compared to medusae.
The present paper describes five new species of candonid ostracods in two genera: Pseudocandona agostinhoi sp. nov., P. cillisi sp. nov., P. claudinae sp. nov., Candobrasilopsis elongata sp. nov. and C. acutis sp. nov. The three species of Pseudocandona belong to the caribbeana-group in this genus. With the two new species of Candobrasilopsis, this genus now comprises four species.
Candobrasilopsis elongata sp. nov. is the most common of the five new species described here, while C. acutis sp. nov. and P. claudinae sp. nov. are known from one locality only, which is furthermore the same for both species: a small streamlet entering the Paraná River. With the description of the present five species, the number of species known from the Paraná River alluvial valley, including the Taquaruçu lakes, now amounts to 49.
A recent paper on the phylogenetic relationships of species within the cephalopod family Mastigoteuthidae meant great progress in stabilizing the classification of the family. The authors, however, left the generic placement of Mastigoteuthis pyrodes unresolved. This problem is corrected here by placing this species in a new monotypic genus, Mastigotragus, based on unique structures of the photophores and the funnel/mantle locking apparatus.
Two new species and one subspecies of Pharnaciini, belonging to two different genera, are described from Vietnam: one species and subspecies of Phryganistria Stål, 1875 and one species of Phobaeticus Brunner von Wattenwyl, 1907. Two species currently attributed to the genus Ramulus Saussure, 1862, Ramulus magnus (Brunner von Wattenwyl, 1907) and R. chinensis (Brunner von Wattenwyl, 1907), are transferred to Baculonistria Hennemann & Conle, 2008 comb. nov. Phobaeticus longicornis Bi & Wang, 1998 and Phobaeticus yuexiensis Chen & He, 1993 represent the male and female of Baculonistria magnus (Brunner von Wattenwyl, 1907) syn. nov. A lectotype is designated for Baculonistria chinensis (Brunner von Wattenwyl, 1907). The genus Baculonistria now contains three species. Nearchus bachmaensis Ta & Hoang, 2004 is transferred to Phryganistria and the new combination Phryganistria bachmaensis (Ta & Hoang, 2004) comb. nov. is proposed. The species is redescribed and the authors’ attribution corrected, the egg is described and figured for the first time.
Phryganistria tamdaoensis sp. nov. is described and figured from both sexes and the egg. Females of P. tamdaoensis sp. nov. are easily recognised by the conspicuously enlarged lanceolate cerci, a character previously unknown in this tribe. The distribution range of Phryganistria heusii heusii (Hennemann & Conle, 1997) is extended to Tam Dao National Park. A new subspecies Phryganistria heusii yentuensis subsp. nov. is described from Tay Yen Tu Nature Reserve from adult males and females and the eggs. Males can easily be distinguished from the nominal subspecies by their colouration. This huge subspecies represents the second longest insect recorded to date. A key to the species of the genus Phryganistria is provided. Phobaeticus trui sp. nov. is described from central Vietnam. It is the first species of Phobaeticus recorded from Vietnam. Adults of both sexes are illustrated.