A new species of the genus <i>Atelopsalis</i> (Acari: Halacaridae) from Zanzibar, Tanzania

A new halacarid species belonging to the genus Atelopsalis is described from the east coast of Zanzibar,Tanzania. Atelopsalis zanzibari sp. nov. is characterized by an anterior areola and two longitudinal costae on anterior dorsal plate, posterior dorsal plate with four costae, genu I with one spine, genu II devoid of spine. This is the first report of the genus Atelopsalis from Tanzania

Three halacarid mites of the genus <i>Copidognathus</i> (Acari: Halacaridae) from Zanzibar, Tanzania

Three new halacarid species belonging to the genus Copidognathus are described from the east coast of Zanzibar, Tanzania. Copidognathus corallicolus sp. nov. is characterized by dorsal setae 2 on membranous cuticle between anterodor­sal plate and ocular plate, posterodosal plate with two single-rosette-pore wide costae, panels on posterodorsal plate sub­divided, long rostrum extending to base of fourth palpal segment, tibia IV with a ventromedial pectinate seta, and tarsi III and IV with 4:3 dorsal setae. Copidognathus fungiae sp. nov. is a member of C. tamaeus group, and characterized by all ventral plates fused in male, posterodorsal plate with two 2- to 3-rosette-pores wide costae, palp a little surpassing anterior end of rostrum, second palpal segment with spinular lamella ventrodistally, ventrolateral lamella of telofemur I with medial edge slightly protruded, and patella IV with 4 setae. Copidognathus ungujaensis sp. nov., a member of C. bairdi group s. str., is closely allied with C. sidellus Bartsch, but differs from it by the presence of areola below second coxal region, almost straight anterior margin of posterodorsal plate, 2 rosette pores between gland pores on posterodorsal plate, lateral and middle costae not joining anteriorly, and more elongated anterior areola on anterodorsal plate

New modelling technique for aperiodic-sampling linear systems

A general input-output modelling technique for aperiodic-sampling linear systems has been developed. The procedure describes the dynamics of the system and includes the sequence of sampling periods among the variables to be handled. Some restrictive conditions on the sampling sequence are imposed in order to guarantee the validity of the model. The particularization to the periodic case represents an alternative to the classic methods of discretization of continuous systems without using the Z-transform. This kind of representation can be used largely for identification and control purposes.Comment: 19 pages, 0 figure

Diets of abundant fishes from beach seine catches in seagrass beds of a tropical bay (Gazi Bay, Kenya)

The composition of the diet of 14 fish species that were common in beach seine catches over the seagrass beds of Gazi Bay (Kenya) was investigated. Three trophic guilds could be distinguished based on dietary diversity and on the numerical and gravimetrical composition of the diet. Herklotsichthys quadrimaculatus, Stolephorus indicus and Atherinomorus duodecimalis were planktivores. Their stomach fullness index was low and the diet was not diverse. The main food items were harpacticoid and calanoid copepods and brachyuran zoea and megalopae. Apogon thermalis, Fowleria aurita, Paramonacanthus barnardi, Mulloides flavolineatus, Lutjanus fulviflamma, L. argentimaculatus and Gerres acinaces were benthivores, mainly feeding on small epi- and hyperbenthic prey. Their diet was very diverse and it was dominated by Amphipoda (Gammaridea), Tanaidacea and Mysidacea. Their fullness indices were low, but a little bit higher than those observed for the planktivores. A third group were the 'piscivores': Bothus myriaster, Fistularia commersonii, Sphyraena barracuda and Plotosus lineatus. The dominant items in the food spectrum of these species were postlarval fishes and large nektonic invertebrates (gammaridean amphipods, mysids, shrimp and crabs). Their diet was not diverse and the fullness index was much higher than that of the other species examined. All other species caught were further classified according to the following feeding guilds: herbivores, planktivores, benthivores (epi- and hyperbenthivores) and piscivores. The ichthyofauna of Gazi Bay was clearly dominated by benthivores

Harpacticoida (Crustacea: Copepoda) associated with cold-water coral substrates in the Porcupine Seabight (NE Atlantic): species composition, diversity and reflections on the origin of the fauna

The harpacticoid copepod fauna associated with the coral degradation zone of Lophelia pertusa (Linnaeus,1758) reefs was investigated for the first time in the Porcupine Seabight (NE Atlantic). The species list of the coral degradation zone includes 157 species, 62 genera and 19 families, and the most species-rich families were Ectinosomatidae (36 species), Ameiridae (29 species) and Argestidae (17 species). At least 80% of the species were considered new to science. Most of the 23 known species have been reported from NE Atlantic coastlines and from higher latitudes in northern Subpolar and Polar Seas. At the family level, the harpacticoid fauna in the Porcupine Seabight did not seem to differ markedly from other deep-sea areas, with essentially the same abundant families. However, the presence of typically epifaunal taxa indicates that the hard substrates of the coral degradation zone provide an exceptional habitat. Further, harpacticoid composition and diversity of sediment and coral fragments were compared with similar substrates in a tropical reef lagoon (Zanzibar, Tanzania). Both regions harboured different fauna and the difference between coral and sediment was more obvious in the tropical lagoon. Species richness and evenness of the two microhabitats in the tropical lagoon were lower than in the deep sea

Atomic Force Microscopy - Laser Scanning Confocal Microscopy imaging protocol for copepod fecal pellets

Within the marine carbon and nitrogen biogeochemical cycles, fecal pellets produced by pelagic and benthic copepods are important microbial activity hotspots as particle substrate for bacteria colonization and as sources of particulate and dissolved organic C and N. We developed a protocol combining Atomic Force Microscopy (AFM) and Laser Scanning Confocal Microscopy (LSCM) to study the peritrophic membrane structure and associated bacteria of fecal pellets produced by a benthic copepod, Paramphiascella fulvofasciata. AFM imaging revealed a fibrillar network structure of the peritrophic membrane, 0.7-5.9 nm thick similar to marine polysaccharides and a-chitin. Bacterial cell volume range was 0.006-0.117 µm3 in liquid. LSCM imaging showed a 3D-heterogeneous microenvironment. This protocol would allow high-resolution interrogation of structural changes and bacterial dynamics within the copepod fecal pellets and other heterogeneous particles such marine snow under environmental conditions