Descriptions of two Copidognathus halacarid mites (Acari, Halacaridae) from Zanzibar, Tanzania

Two halacarid species of the genus Copidognathus (Acari, Halacaridae) collected from the east coast of Unguja, Zanzibar, Tanzania, are described. Copidognathus matemwensis sp. nov. is characterized by an anterodorsal plate with 3 areolae, posterior dorsal plate with 2 costae, pair of ventromedial areolae between lateral and posterior setae on anterior epimeral plate, areolae present on lateral side of anterior half of genitoanal plate tending to join the areolae laterally to the genital opening area, rostrum elongate, tibiae I and II each with 1 denticulate process proximoventrally. The male of Copidognathus corallorum (Trouessart, 1899) is reported for the first time and described; leg morphology for C. corallorum is provided

A checklist of the marine Harpacticoida (Copepoda) of the Caribbean Sea

Recent surveys on the benthic harpacticoids in the northwestern sector of the Caribbean have called attention to the lack of a list of species of this diverse group in this large tropical basin. A first checklist of the Caribbean harpacticoid copepods is provided herein; it is based on records in the literature and on our own data. Records from the adjacent Bahamas zone were also included. This complete list includes 178 species; the species recorded in the Caribbean and the Bahamas belong to 33 families and 94 genera. Overall, the most species family was the Miraciidae (27 species),followed by the Laophontidae (21), Tisbidae (17), and Ameiridae (13). Up to 15 harpacticoid families were represented by one or two species only. Excluding the Bahamian records, the number of species recorded herein for the Caribbean Basin is 139. The distribution of the species richness within the Caribbean Basin is asymmetrical; the northwestern sector (Mexican Caribbean) is the most species, it concentrates up to 45% of the species recorded in the Caribbean. The insular Caribbean is nearly as diverse as the continental areas (75 vs 83 species recorded, respectively). The dominance of taxa related to coastal systems with coarse and fine sands and carbonatesediments reveals the general trend in the type of habitats surveyed in the Caribbean Sea. Up to 37 species found in the Mexican Caribbean represent new records for this country. There are enormous hiatuses in the knowledge of the Caribbean harpacticoids in terms of geographic, bathymetric, and environmental coverage. It is expected this list will grow rapidly and many undescribed forms will be discovered when understudied or unexplored environments are surveyed in detail

Spiniferaphonte, a new genus of Laophontidae (Copepoda: Harpacticoida), with notes on the occurrence of processes on the caudal rami

A new genus and species of Laophontidae, Spiniferaphonte ornata n. gen., n. sp., is described from the coast of Kenya. The new genus is closely related to Laophontina and Wellsiphontina as shown by the following synapomorphies: a denticulate operculum, a sexually dimorphic P4 exopod (reduced chaetotaxy of the ultimate segment in the male), and the absence of sexual dimorphism in the P2 and P3 endopods. The two-segmented exopod of PI and the presence of a seta on the endopodal part of the male P5 are plesiomorphies indicating that the new genus represents a separate lineage within this group. The proposal of the new genus Spiniferaphonte is supported by the following autapomorphies: three smooth setae on the female P5 exopod and a robust, dorsally bent, and strongly sclerotised caudal seta V. Within the Laophontidae, it is striking that the presence of distinct, thorn-like processes on the caudal rami is limited to interstitial genera. Distinct processes on the proximal segments of the antennule and a proximally thickened caudal seta V also appear to be associated with this interstitiality. These structures may play a role in the movement and the anchoring of the animals in their interstitial habitat

Copepods controlling bacterial communities on fecal pellets

The traditional view of the marine food web depicts bacteria and copepods (mainly planktonic species) as separate units, indirectly connected via nutrient cycling and trophic cascade processes. In contrast, several recent studies have demonstrated that zooplankton and bacteria directly interact, physically, e.g. bacteria attached to zooplankton bodies and biologically, e.g. zooplankton feeding supports bacterial growth through their excretions. Copepods produce large numbers of fecal pellets in the marine environment. Almost immediately after egestion, pellets host extensive bacterial communities. Low amounts of fecal material in sediment traps indicate most part of fecal pellet production is retained in the water column as a result of high microbial degradation rates and planktonic copepods reworking the fecal pellets. First observations on the re-use of feces by benthic copepods points out that these crustaceans profit in a yet unknown way from fecal pellet bacteria. Recently it was illustrated that the benthic species Paramphiascella fulvofasciata increases its fecal pellet production according to its food source. Presumably the bacteria associated with fecal pellets create a trophic upgrading of the fecal material. A detailed characterization of these bacteria is crucial to understand the trophic pathways in the lower marine food web. Culture-independent molecular techniques (e.g. DGGE) showed the specificity of these communities. Shifts in the bacterial communities are caused by age, original food source (e.g. diatoms) and producer of the fecal pellet. Moreover, an additional grazing experiment illustrated the importance of the freshness of the initial food source for grazing preferences but also for the bacterial communities on the fecal pellets. Food of low quality was compensated by more diverse bacterial communities that were available for additional grazing. These results illustrated the importance of fecal bacteria in the transformation of organic matter and energy transfer in marine sediments

Pigment and fatty acid profiling reveal differences in epiphytic microphytes among tropical Thalassodendron ciliatum meadows

Tropical seagrasses support abundant and diverse epiphytic microalgae that form the base of seagrass food webs. To help better understand the influence of structural variability of tropical seagrass meadows on associated microalgal epiphytes, we quantified the relative abundance and distribution of epiphytic microphytes in subtidal meadows of Thalassodendron ciliatum with varying seagrass canopy structure, using pigments and fatty acid (FA) profiling. We observed significant differences in microalgal epiphytic communities (diatoms and Rhodophyta) among four seagrass meadows, which was best explained by seagrass leaf surface area. Contrary to expectations, seagrass meadows with lower leaf surface area supported higher relative epiphytic microphyte abundance than those with higher leaf surface area. These results increase understanding of how spatial variability of structural components in seagrass meadows can influence their functional components, with implications on the availability to primary consumers

Two new genera of Laophontidae (Copepoda: Harpacticoida) without sexual dimorphism in the endopods of the swimming legs

Two new monospecific genera of the harpacticoid family Laophontidae T. Scott, 1905 are described here. Apistophonte wasiniensis gen. et sp. n. was found along the Kenyan coast and Propephonte duangitensis gen. et sp. n. along the northern coast of Papua New Guinea. They differ from most other laophontid genera in the absence of sexual dimorphism in the endopods of the swimming legs. At first sight, both new species resemble each other very closely in habitus, integumental ornamentation, chaetotaxy of the swimming legs and absence of sexual dimorphism in the endopods. However, the detailed characteristics of A1, maxilla and male P5 show that the species are not congeneric. The structure of the first antennular segment of Propephonte gen. n. suggests a close relationship with Peltidiphonte Gheerardyn and Fiers, 2006. The exact affinities of Apistophonte gen. n. however remain difficult to assess

Temperature affects the use of storage fatty acids as energy source in a benthic copepod (Platychelipus littoralis, Harpacticoida)

The utilization of storage lipids and their associated fatty acids (FA) is an important means for organisms to cope with periods of food shortage, however, little is known about the dynamics and FA mobilization in benthic copepods (order Harpacticoida). Furthermore, lipid depletion and FA mobilization may depend on the ambient temperature. Therefore, we subjected the temperate copepod Platychelipus littoralis to several intervals (3, 6 and 14 days) of food deprivation, under two temperatures in the range of the normal habitat temperature (4, 15 degrees C) and under an elevated temperature (24 degrees C), and studied the changes in FA composition of storage and membrane lipids. Although bulk depletion of storage FA occurred after a few days of food deprivation under 4 degrees C and 15 degrees C, copepod survival remained high during the experiment, suggesting the catabolization of other energy sources. Ambient temperature affected both the degree of FA depletion and the FA mobilization. In particular, storage FA were more exhausted and FA mobilization was more selective under 15 degrees C compared with 4 degrees C. In contrast, depletion of storage FA was limited under an elevated temperature, potentially due to a switch to partial anaerobiosis. Food deprivation induced selective DHA retention in the copepod's membrane, under all temperatures. However, prolonged exposure to heat and nutritional stress eventually depleted DHA in the membranes, and potentially induced high copepod mortality. Storage lipids clearly played an important role in the short-term response of the copepod P. littoralis to food deprivation. However, under elevated temperature, the use of storage FA as an energy source is compromised