Streptocephalus caljoni n.sp. (Crustacea: Anostraca) from Burundi and analysis of its limb structure

Streptocephalus caljoni n. sp. from Burundi is described. It is related to Streptocephalus trifidus, but differs from it and other Streptocephalus in the cheliform hand of the male antenna II. We also analyse the morphology of the setae on the endo- and exopodite of the fifth trunk limb, using light- and scanning electron microscopy. This analysis reveals additional differences between the two related species, and is a useful tool in the study of the taxonomy of the Anostraca.     

Daphnia (Ctenodaphnia) hispanica sp. nov., a new daphnid (Cladocera) from Spain

Daphnia (C.) hispanica n. sp. has thoracic limbs of A D. (C.) atkinsoni type and is very similar toD. chevreuxi Richard, 1896. With this speciesD. (C.) hispanica shares the presence of a soft accessory seta on the outer side of the trunk of the first thoracic limb, apparently unique among the genusDaphnia. Although other morphological characteristics are very similar in this two species, a detailed comparison reveals that they can easily be separated as different species. The most useful features in differentiating both species are:D. (C.) hispanica has a dorsal crest in the head, its rostrum is longer, its accesory seta of the first thoracic limb is more developed, the juveniles are not helmeted and its male postabdomen lacks individual denticles on the anal and preanal margin.The new species is, up to now, restricted to Spain and inhabits the temporary and low mineralized waters of the steppe regions.     

Redescription of Branchinecta granulosa Daday, 1902 from Argentina (Crustacea: Branchiopoda)

The species Branchinecta granulosa Daday 1902, is redescribed on the basis of adult material from near Facundo (Chubut Province, Argentina). Its relationship to its regional congeners is outlined.     

Branchinecta belki n. sp. (Branchiopoda: Anostraca), a new fairy shrimp from Mexico,hybridizing withB. packardi Pearse under laboratory conditions

A new fairy shrimp,Branchinecta belki n.sp., endemic to the south of Coahuila state is described and figured. A total of nine species of phyllopods, including the new species, occur in ponds in the type area.The laboratory hybridization ofB. belki andB. packardi through no-choice mating tests in reciprocal crosses is discussed. A mixture of characteristics of parental species is present in male F1 and F2 hybrids. This may provide a biological tool, or search image (sensu Wiman, 1979a), for detecting male hybrids, should such exist, between theBranchinecta species of this study in nature. In addition to the reported interspecific hybridizations inStreptocephalus (Wiman, 1979a & 1979b) and inArtemia (Bowenet al., 1985) under laboratory conditions, the new evidence inBranchinecta suggests that absence of efficient premating mechanisms may be common in Anostraca.     

Echiuropus bekmanae n.sp. (Crustacea, Amphipoda, Carinogammaridae) from Lake Baikal, retrieved by a new deep-water sampling device

Lake Baikal is well known for its exceptional diversity of gammarid amphipods, with 95% of endemics from its 270 described species representing about 20% of the world freshwater fauna. Echiuropus (Asprogammarus) bekmanae n.sp. was collected by an `autonomous trap system', a sampling device thoroughly described here. Although not necrophagous itself, this new species was found in two baited trap samples (at 750 and more than 1600 m) from 1995 and 1996. This rather small (13 mm) deep water species is the eighth species of the subgenus Asprogammarus, of the Baikal endemic genus Echiuropus. Diagnoses of the subgenus and the closer species are given.     

Description of Pratylenchoides camachoi n. sp. (Tylenchida: Pratylenchidae) from Spain

Pratylenchoides camachoi n. sp. from rosemary (Rosmarinus officinalis L.) in Sierra De Cazorla in southeastern Spain is described and illustrated. Pratylenchoides camachoi n. sp. is a bisexual species characterized by a cylindroid, sometimes clavate-shaped, male tail with a uniquely shaped smooth, rounded terminus. Females are characterized by a short esophageal overlap and six lines in the lateral field, which reduce to four in the tail region; not areolated except outer bands in the esophageal and tail regions.     

Two new species of polychaetes from the sublittoral bottoms off Antofagasta, Northern Chile: Clymenella fauchaldi n. sp. (Maldanidae) and Mooreonuphis colosensis n. sp. (Onuphidae)

Individuals belonging to two new species, from two genera Clymenella Verril (Maldanidae) and Mooreonuphis Fauchald (Onuphidae), have been collected and described from a sublittoral bottom area close to Antofagasta, northern Chile. The environment consists of medium to fine sands and the samples have been collected at ca. 60 m depth. Clymenella fauchaldi sp. n. is closely related to Clymenella minorArwidsson, 1911, but clearly differs from other species of the genus in the type of notochaetae, winged capillaries, and neurochaetae, thick acicular spines, that are borne on the first chaetigers. Mooreonuphis colosensissp. n.is related to Mooreonuphis nebulosa (Moore, 1911) and Mooreonuphis peruana (Hartman, 1944), but differs mainly in the form of the mandibles, in the maxillary formula, location of the subacicular hooks on chaetigers, number of the ceratophore rings and the length of the medium and lateral antennae styles.     

Hadodiaptomus dumonti n. gen., n. sp., a new freshwater stygobitic calanoid (Crustacea: Copepoda: Calanoida) from Vietnam (South Asia) and a new member of the subfamily Speodiaptominae Borutzky, 1962

A new species of freshwater stygobitic calanoid, Hadodiaptomus dumonti n. gen., n. sp., from a cave in Vietnam (South Asia) is described. It is the ninth taxon from the order Calanoida described from freshwater subterranean (i.e. cave) environments. It is the fourth member of the subfamily Speodiaptominae Borutzky, 1962. It differs from stygobitic taxa in Europe and Mexico by numerous characters, especially in the armature of P1–P5, antenullas, mouth parts and genital segments in both sexes. Arthrodial membrane development from CII to CV is different from epigean as well as from subterranean taxa. These differences suffice to raise a new genus–Hadodiaptomus, characterised by two-segmented exopodites and endopodites of P1–P4 and reduced P5 endopodites in both sexes. Males are without widened segments 13–18 on right A1. Relations with other stygobitic taxa of the subfamily Speodiaptominae are discussed.     

Observations on the biology of the rare Branchipus visnyai Kertesz 1956 (Crustacea, Anostraca) from Monti Reatini (Latim, central Italy)

Branchipus visnyai is presently known from only one location, in Italy, on Monte Catabio (central Appennine, Latium, 1590 m a.s.l). It lives in a large astatic pond and in a small temporary pool close to the pond. Typically two generations appear in the pond (in spring after snowmelt and in autumn after dilution by rainfall), unless an exceptionally dry season occurs. Yet, due to shallowness and small size, filling and duration of the pool is erratic and depends on the annual amount of snow and rainfall. Consequently, B. visnyai does not always appear in the pool.Field studies suggest that either a rise in temperature or a drop in conductivity may trigger cyst hatching in the two biotopes. Also, the species exhibits a high tolerance to change in environmental factors like water temperature. Hatching occurs within a range of 10–22 °C, adults survive at temperatures from 1 to 27 °C. The optimum seems to correspond to 10–20 °C.     

Cricotopus (Cricotopus) nevadensis sp. n. (Diptera,Chironomidae) from Sierra Nevada (southern Spain)

Male and female imagines, and pupal exuviae of Cricotopus (C.) nevadensis sp. n. are described. A discussion on the systematic position, a differential diagnosis and notes on the ecology of this new species are given.     

The genus Mixodiaptomus Kiefer, 1932 (Copepoda,Diaptomidae) in Spain

The distribution of the Calanoid genus Mixodiaptomus was studied in a large number of pools and small lakes scattered over Spain. Four species occur: M. incrassatus, M. kupelwieseri, M. ortizi and M. laciniatus, the latter in 2 subspecies (M. laciniatus laciniatus and M. laciniatus atlantis). M. ortizi is described as a new species. M. laciniatus lives in mountains, while all other species occur in the plains. M. incrassatus is found all over the country, M. kupelwieseri only in the eastern part of Catalonia, M. laciniatus atlantis in Andalucia and M. ortizi in the central lands called Mesetas. All live in little mineralized waters and only M. incrassatus and M. laciniatus atlantis occur in clayey waters.     

Crustacean assemblage and environmental characteristics of a man-made solar saltwork in southern France,with emphasis on anostracan (Branchiopoda) population dynamics

Physical and chemical variables, anostracan populations (Artemia parthenogenetica and Branchinella spinosa) and other biota were studied during 1996–1997 in a Camargue saltern (max. depth 1 m). The taxonomic composition and density of macroinvertebrates were investigated twice monthly, based on benthic substrate and water column samples. Fauna was composed of three groups in terms of numerical importance. The benthic macroinvertebrates were represented only by nematodes (< 50 ind. m^–2 to > 500 ind. m^–2 in November–December and May respectively). The zooplankton was dominated by crustaceans, one cladoceran, Moina salina (ranging from 670 to 2350 ind. m^–2 in spring), two anostracans, Artemia parthenogenetica (< 50 ind. m^–2 in autumn), and Branchinella spinosa (max. 190 ind. m^–2 in December to absent in April), and two copepods, Cletocamptus retrogressus (max. density 2000 ind. m^–2 in November), and Eurytemora velox (max. density 650 ind. m^–2 in February–March). Insects (Chironomidae, Culicidae) were rare, with mean densities < 1 ind. m^–2. The phenology of each crustacean population is discussed in relation to physical and chemical water variables. Salinity appeared to be of greatest importance regulating the population abundance.     

Chirocephalus ponticus n.sp. (Crustacea: Anostraca) and its affinities to the other Turkish species of the genus

Chirocephalus ponticus n.sp. (Crustacea: Anostraca) from Turkey is described. The new species is characterized by the form of the second antenna and the frontal appendages of the male. This species seems to be related to C. turkestanicus Daday. Furthermore, analysis of limb structure reveals differences between the three Chirocephalus species previously known from Turkey: C. paphlagonicus, C. vornatscheriand C. diaphanus. New localities for these species are reported. This revised version was published online in August 2006 with corrections to the Cover Date.     

Leptepsilonema santii sp.n. from Spain and data on the variability ofL. filiforme (Nemata,Epsilonematidae)

The genusLeptepsilonema is recorded for the first time from the Mediterranean:L. santii sp.n. is characterised by a slender body with a large number of annules (122–128). Cuticular ornamentation with clear ridges and a lateral field of small thorns on both sides of the anteriormost annules are also typical as well as the number and arrangement of copulatory thorns (2–3 pairs, 2 fields), the shape and length (49–58 µm) of spicules in males.L. filiforme is recorded from New Caledonia; specimens largely resemble the original types but are larger. The variability of some morphological structures is discussed.     

Mongolodiaptomus dumonti n. sp., a new freshwater copepod (Calanoida,Diaptomidae) from Thailand

Mongolodiaptomus dumonti n. sp. from several localities in northeast Thailand is described and figured. The new species shares some features with Mongolodiaptomus gladiolus (Shen & Lee), M. calcarus (Shen & Tai) and M. rarus (Reddy, Sanoamuang & Dumont), thus the gladiolus-group is created. However, it stands out in the female, by the extraordinary large postero-laterally spine at left proximal margin of genital somite. In the male, the right caudal ramus has a large tooth and a bilobed knob on ventral side; basis of the right P5 has a distinct, spur-like process on mid-distal surface; the second exopodite-segment of the right P5 has characteristically irregular outer margin, enlarged at proximal 1/3, but narrowed at distal 2/3 and bearing three lateral spines of unequal sizes; the inner margin of basis of the left P5 is fringed with a narrow hyaline lamella and dilated distally in lateral angle.