Redescription and assignment of Alona globulosa Daday, 1898 to a new genus Notoalona and a description of Notoalona freyi sp. nov.

The species Daday (1898) describes as Alona globulosa has been critically studied, based on many populations from tropical and subtropical regions of the world, over its whole geographical range. A new species and a new subspecies are described. Based on the morphological characters of this species group, which are markedly different from those of the genera previously used for this species, namely Alona, Alonella, and Indialona, a new genus Notoalona is established. N. globulosa (Daday, 1898) is designated as the type species. Morphological differences of Notoalona, Alona, Alonella, and Indialona are discussed. The diagnostic characters of the genus Notoalona include 1) two bean-like thickenings as headpores on the headshield, 2) a row of submarginal setae along the posterior half of the ventral margin of carapace, 3) first trunk limb ODL with one seta and IDL with 3 setae and a small seta-like notch, 4) small branched seta dorsal to posterior lobe of trunk limb-I, 5) entire carapace of the ephippial female modified as an ephippium with a foamy mass surrounding the egg. N. globulosa has a wide distribution in Asia, Africa, and Australia. The Australian material has been designated as the subspecies australiensis. N. freyi sp. nov. is known only from Florida, USA. More detailed studies are necessary to evaluate the taxonomic status of other populations from America including material described as Alonella sculpta, which certainly belongs to the genus Notoalona.     

A New Species of the Chydorus sphaericus Group (Cladocera,Chydoridae) from Western Montana

Chydorus biovatus differs from C. sphaericus sens. str. in that the ephippial female carries two resting eggs, for which the brood pouch is expanded dorsally. resulting in a sharp angle in lateral contour near the junction of the head and shell and in the postpore distance being much elongated. The mature male has the pre-anal angle of the postabdomen rounded and the rostrum broadly rounded, both features being much different than in C. sphaericus sens. str. In North America there is a progressive replacement of C. brevilabris-group species in the South to C. sphaericus-group species in the Far North. Production of two resting eggs by Chydorus piger is recorded.     

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.     

Responses to injured conspecifics and heterospecifics by water fleas,Chydorus sphaericus

Cladocerans have been shown to exhibit a variety of responses to chemical stimuli associated with predation risk, including those from predators and injured conspecifics. In this study, we tested the hypothesis that individuals of Chydorus sphaericus would respond with avoidance behavior to chemical cues from both injured conspecifics and injured heterospecifics. Avoidance behavior was seen in response to cues from C. sphaericus and Daphnia magna. Responses to cues from Daphnia pulex were intermediate between those of the other cues and the water control. We propose that a concentration effect may be responsible for the mixed responses to heterospecific cues and speculate that responses to a broad range of cues may help explain the expansive range of C. sphaericus.     

A Review of the Genera Croconema Cobb, 1920 and Pseudochromadora Daday, 1899 (Nematoda, Desmodoroidea): New Species from the Coasts of Kenya and Australia

This article is a review of the subfamily Desmodorinae (Nematoda, Desmodoroidea) and two related genera within this subfamily, Croconema Cobb, 1920 and Pseudochromadora Daday, 1899 with keys to genus or species level, genus diagnoses and lists of valid species. An emended diagnosis of, and discussion on, Sibayinema Swart & Heyns, 1991, is presented. Three new species are described: Croconema floriani sp.n. from the coast of Kenya, Pseudochromadora galeata sp.n. and P. securis sp.n. from the coast of Australia.     

Chydorus arcticus n.sp., a new cladoceran crustacean (Chydoridae: Chydorinae) from the North Atlantic arctic and Subarctic areas

Chydorus arcticus n.sp. (Cladocera: Chydoridae: Chydorinae) is described, figured, and differentiated from the closely relatedC. sphaericus (O.F. Müller, 1785). The known distribution of the species is given, and some aspects of speciation of arctic crustaceans are pointed out.     

Complex relations between freshwater macro- and meiobenthos: interactions between Chironomus riparius and Chydorus piger

• 1 The potential importance of interactions between macro- and meiobenthos in the littoral zone of takes was studied in a series of laboratory experiments with a chironomid and a chydorid.
• 2 In a situation of intraspecific density dependence, Chydorus piger Sars inhibited the growth of Chironomus riparius Meigen, while both second- and fourth-instar C, riparius stimulated the parthenogenetic reproduction of C. piger.
• 3 The meiofaunal chydorids may thus have a structuring effect on macrofaunal chironomid populations by interfering with the early-instar larvae.
• 4 With macro- and meiofaunal species both operating at the primary consumer-level of the food web, this kind of complex interaction will affect the magnitude of secondary production available to higher trophic levels.

     

Sex in a cyclical parthenogen: mating behaviour of Chydorus sphaericus (Crustacea; Branchiopoda; Anomopoda)

1. We describe the interactions during mating in Chydorus sphaericus, a cyclical parthenogenetic anomopod. Mating behaviour is more complex than previously assumed, with evidence for a diffusible chemical to which males react at the onset of mating, for reproductive isolation, and for postcopulatory mate guarding. 2. During mating, the male and female form a ‘mating cross’ that may be maintained for several hours, while copulation itself typically lasts less than a minute. Furthermore, males invariably attach to the right valve of females. Copulation involves intromission of the postabdomen between the valves, so that the gonopores approach the left ovarium. 3. This behaviour is reflected in the morphology of both sexes: males have a specialised anterior valve margin, postabdomen, first limb and rostrum, under selective pressure for successful mate guarding and copulation, while gamogenetic females have asymmetric ovaries, and a species‐specific setulation of the valves. Males of the structurally related Chydorus ovalis react to the presence of C. sphaericus, but fail to dock to females, suggesting a lock‐antilock element in the reproductive isolation of both species. 4. The morphological and ethological adaptations in C. sphaericus suggest that there is a strong selective pressure on mating behaviour in this cyclical parthenogen and specifically towards the formation of the ‘mating cross’.     

Tintinnophagus acutus n. g., n. sp. (Phylum Dinoflagellata), an Ectoparasite of the Ciliate Tintinnopsis cylindrica Daday 1887, and Its Relationship to Duboscquodinium collini Grassé 1952

ABSTRACT. The dinoflagellate Tintinnophagus acutus n. g., n. sp., an ectoparasite of the ciliate Tintinnopsis cylindrica Daday, superficially resembles Duboscquodinium collini Grassé, a parasite of Eutintinnus fraknoii Daday. Dinospores of T. acutus are small transparent cells having a sharply pointed episome, conspicuous eyespot, posteriorly positioned nucleus with condensed chromosomes, and rigid form that may be supported by delicate thecal plates. Dinospores attach to the host via a feeding tube, losing their flagella, sulcus, and girdle to become spherical or ovoid cells. The trophont of T. acutus feeds on the host for several days, increasing dramatically in size before undergoing sporogenesis. Successive generations of daughter sporocytes are encompassed in an outer membrane or cyst wall, a feature not evident in trophonts. Tintinnophagus acutus differs from D. collini in host species, absence of a second membrane surrounding pre‐sporogenic stages, and failure to differentiate into a gonocyte and a trophocyte at the first sporogenic division. Phylogenetic analyses based on small subunit (SSU) ribosomal DNA (rDNA) sequences placed T. acutus and D. collini in the class Dinophyceae, with T. acutus aligned loosely with Pfiesteria piscicida and related species, including Amyloodinium ocellatum, a parasite of fish, and Paulsenella vonstoschii, a parasite of diatoms. Dubosquodinium collini nested in a clade composed of several Scrippsiella species and Peridinium polonicum. Tree construction using longer rDNA sequences (i.e. SSU through partial large subunit) strengthened the placement of T. acutus and D. collini within the Dinophyceae.     

Revision of the genus Haemonchus Cobb, 1898 (Nematoda: Trichostrongylidae)

Summary Only nine species of the genus Haemonchus are considered valid, namely, H. contortus (Rudolphi, 1803) Cobb, 1898 (type), H. bedfordi Le Roux, 1929, H. dinniki Sach, Gibbons & Lweno, 1973, H. krugeri Ortlepp, 1964, H. lawrencei Sandground, 1933, H. longistipes Railliet & Henry, 1909, H. mitchelli Le Roux, 1929, H. similis Travassos, 1914 and H. vegliai Le Roux, 1929. These are redescribed. H. bispinosus Molin, 1860, H. placei Place, 1893, H. cervinus Baylis & Daubney, 1922, H. okapiae van den Berghe, 1937 (in part), H. tartaricus Evranova, 1940, H. contortus contortus Das & Whitlock, 1960, H. contortus cayugensis Das & Whitlock, 1960, H. contortus bangalorensis Rao & Rahman, 1967, H. contortus hispanicus Martínez Gómez, 1968, H. contortus kentuckiensis Sukhapesna, 1974 and H. contortus var. uktalensis Das & Whitlock, 1960 are considered synonyms of H. contortus (Rudolphi, 1803) Cobb, 1898.The synonymy of H. lunatus Travassos, 1914, H. atectus Lebedev, 1929, H. pseudocontortus Lebedev, 1929 and H. fuhrmanni Kamensky, 1929 with H. contortus is confirmed. H. okapiae van den Berghe, 1937 (in part) is considered a synonym of H. mitchelli Le Roux, 1929 and H. bubalis Chauhan & Pande, 1968 is considered a synonym of H. similis Travassos, 1914. H. bovis Bonelli, 1941 and H. contortus var. kashmirensis Fotedar & Bambroo, 1965 are considered species inquirendae. An illustrated key to the species of the genus is provided.Part of a thesis approved by the University of London for the award of the Ph.D. degree.Part of a thesis approved by the University of London for the award of the Ph.D. degree.     

Three new species of Carnoya Gilson, 1898 (Nematoda: Rhigonematidae) from Papua New Guinea

Summary Three new species of Carnoya Gilson, 1898 are described and illustrated from two species of rhinocricid millipedes from Papua New Guinea. C. fimbriata n.sp., C. perbella n.sp. and C. strobilina n.sp. are easily distinguished from the other described species of Carnoya by the exceptionally long tail. They are distinguished from one another by differences in spine configuration, head shape, vulval position and lateral ala shape in the females and by the presence or absence of a spine collar, the lateral ala shape and the copulatory papillae arrangement in the males. Scanning electron micrographs of the females of all three species are provided. ac]19840913     

Subgeneric differentiation within Kurzia (Crustacea: Anomopoda: Chydoridae) and a new species from Central America

The genus Kurzia is divided into two subgenera: Kurzia s. str. and Rostrokurzia n. subg. Subgenus Kurzia includes Kurzia (K.) latissima Kurz, 1874, with a palearctic -, Kurzia (K.) polyspina n. sp. with a neotropic - , and Kurzia (K.) cf. media (Birge, 1879) with a nearctic distribution. Rostrokurzia includes Kurzia (R.) longirostris Daday, 1898 (pantropical distribution), and Kurzia (R.) brevilabris Rajapaksa & Fernando, 1986, from subtropical and tropical Asia. Kurzia latissima Kurz, 1874, from Central Europe is redescribed in detail.     

The first report of the non-indigenous Chydorus brevilabris Frey, 1980 (Crustacea: Cladocera) in Asian freshwaters

Limnology - Chydorus sphaericus (O.F. Müller, 1776) (Crustacea: Cladocera) sensu stricto is distributed in Europe: C. sphaericus-like organisms in other regions represent a group of...     

Relocation of Chydorus barroisi and related species (Cladocera,Chydoridae) to a new genus and description of two new species

Five taxa already in the literature are here removed from Chydorus to their own genus Ephemeroporus, and two new species — E. acanthodes and E. archboldi — are described, with E. acanthodes being designated the type species of the genus. These taxa, plus at least nine undescribed species and others undoubtedly waiting to be sorted out, constitute a tightly circumscribed group of species morphologically. The first two species described — E. barroisi and E. poppei — are nomina dubia for the present, as no specimens exist from the original collections, nor are any available from the type localities or reasonably close thereto. E. hybridus from Brazil has been characterized in greater detail through the availability of specimens from the type series, which has enabled one of the species in the E. hybridus group from North America to be judged conspecific with reasonable certainty. E. tridentatus, from Brazil, has been restored as a valid species, and the highly distinctive E. phintonicus from Sardinia and Algeria constitutes the seventh species in the genus. Chydorus nitidulus and Chydorus tilhoi, which have been suggested to be members of the barroisi complex, are not. What are presently called E. barroisi and E. hybridus, except for E. hybridus, sens. str., each consists of a cluster of species sharing the same number of teeth on the labrum and shell. Because of their wide, distribution, abundance, and frequency of occurrence, especially in South Asia, the species in the E. barroisi group will be especially meaningful to sort out.     

Record of genus Pseudocypris Daday, 1908 (Crustacea: Ostracoda) with the description of a new species from India

The genus Pseudocypris Daday, 1908 is recorded from India for the first time and one new species, P. patialaensis sp. nov. is described.