Glaciella,a new genus of freshwater Canthocamptidae (Copepoda,Harpacticoida) from a glacier in Nepal,Himalayas

A new genus and new species of Canthocamptidae: Glaciella yalensis (Copepoda: Harpacticoida) from the surface of Yale Glacier, Nepal is described. This new species was collected from cryconite-pit on the surface of the glacier and is closely related to genus Maraenobiotus, but easily distinguishable from its species in the following: 1) segments and setae on endopodites of legs 2–4 in the male differing shape, 2) exopodites of male legs 3–4 with modified setae, 3) caudal seta in female absent. Body color of this copepod is red in live specimens.Contributions No. 86 Itako Hydrobiological Station, Ibaraki University.     

Postembryonic development in Diaphanosoma brachyurum (Lievin, 1848) (Crustacea: Ctenopoda: Sididae)

Postembryonic females and males Diaphanosoma brachyurum from Lake Glubokoe (Moscow) have 3–4 and 3 juvenile instars, respectively. Females and males of the first three postembryonic instars can be identified by the different number of setae and setal rudiments on the proximal and distal segments of the exopodite of the swimming antennae: 3 + 7; (i + 3) + 7; 4 + (i + 7), respectively (i = rudiment of seta). The subsequent instars have 4 + 8 long plumose setae on these segments, but the fourth instar has the proximal lateral seta of the distal exopod segment slightly shorter and thinner than the others. The antennules and copulatory appendages of males are instar-specific. Diaphanosomas show small increments in body length during the postembryonic molts. The largest increments (about 115 m) occur during the first or second molts. The allometric equation of Huxley (1924) was used for a comparison of the relative growth rate of different body parts. In the middle of summer, the head and swimming antennae with the body and the antennal exopodite with the antennal basipodite grow in isometry. At the same time, the branches of the swimming antennae and their setae show allometric growth: the exopodite and distal setae grow faster than the endopodite and the lateral setae, respectively.     

Larval development of Octomeris sulcata Nilsson-Cantell (Cirripedia: Thoracica: Chthamalidae) from Japan and Korea

Embryos obtained from gravid adults of the chthamalid barnacle Octomeris sulcata Nilsson-Cantell from Japan and Korea were cultured through six naupliar stages to the cyprid and juvenile barnacle stage in laboratory conditions, fed either the diatom Skeletonema costatum (Grev.) Cleve or the dinoflagellate Prorocentrum minimum (Pavillard) Schiller. The nauplii were planktotrophic and, depending on diet, reached the cyprid stage 9 or 17 days after hatching in individual cultures at 22 °C with 24 h illumination. The survival rate was higher and the duration of the naupliar stages was shorter when fed P. minimum rather than S. costatum. This is probably due to the presence of feathered setae on the antennae. Feathered or plumose setae in nauplii of different cirripede taxa are apparently linked to the type of phytoplankton in the seas when these taxa first evolved.The larval stages of O. sulcata are described, and morphological differences between larvae reared from Japanese andKorean adults are compared. The polygonal cephalic shield and unilobed labrum, a pair of posterior shield spines after naupliar stage IV, feathered setae and a hispid seta on the coxa of the antenna, a cuspidate seta on the mandible, and the gnathobase of the antenna are important in distinguishing the nauplii of this species from other species, including Chthamalidae.     

Setal variability of <Emphasis Type="Italic">Hydrozetes lemnae</Emphasis> and <Emphasis Type="Italic">H. thienemanni</Emphasis> (Acari: Oribatida: Hydrozetidae)

Setal variability and the other morphological characters of juvenile stages and adult of Hydrozetes lemnae (Coggi, 1897) and H. thienemanni Strenzke, 1943 were investigated. In the juveniles of both species the length and shape of some setae vary, especially in the gastronotic region, more so in H. lemnae, which is parthenogenetic and reproduces by thelytoky, than in H. thienemanni, which is dioecious. The former species usually has more thick setae in the anterior and medial regions of the gastronotum, especially in the larva, compared to the latter. In the juveniles of H. lemnae the prodorsal setae le and in are longer, and in the nymphs the gastronotal setae of the l-series are usually longer than in H. thienemanni. These species differ distinctly by the number of long setae in the posterior part of the nymphs; in H. lemnae three pairs of long setae occur, while in H. thienemanni only two pairs; the respective juvenile stages of H. lemnae are also smaller than those of H. thienemanni. In the adults the number of c-series setae varies, as seta c ₁ is lost, and in some individuals also seta c ₃, and only seta c ₂ remains.     

Giselinidae fam. nov., a new monophyletic group of cyclopoid copepods (Copepoda, Crustacea) from the Atlantic deep sea

Four new species of Cyclopoida from deep-sea waters are described and placed in two new genera: Giselina gen. n. and Sensogiselina gen. n. The new genera and species belong to a new monophyletic group within the cyclopinid cyclopoids. A new name, Giselinidae, is proposed for this monophylum. The new family is characterised by the combination of the following characters: (1) tergite of leg 1 fused to cephalosome dorsally, but incompletely fused laterally, (2) absence of aesthetascs on ancestral antennulary segments XVI, XXI and XXV, (3) absence of antennary exopodal setae, (4) presence of only three spines on distal exopodal segment of leg 1, (5) absence of inner setae on first endopodal segments of legs 1–4, (6) outer terminal and distal inner elements of distal endopodal segment of leg 4 transformed into spines, (7) distal outer element of leg 5 exopod transformed into a spine, (8) leg 6 with only one seta, and (9) furcal setae I and III located on dorsal margin. Received in revised form: 16 June 2000 Electronic Publication     

Larval development of Japanese 'conchostracans': part 2, larval development of Caenestheriella gifuensis (Crustacea, Branchiopoda, Spinicaudata, Cyzicidae), with notes on homologies and evolution of certain naupliar appendages within the Branchiopoda

As part of a larger project examining and comparing the ontogeny of all major taxa of the Branchiopoda in a phylogenetic context, the larval development of Caenestheriella gifuensis (Ishikawa, 1895), a Japanese spinicaudatan ‘conchostracan’, is described by scanning electron microscopy. Seven different larval stages are recognised, in most cases based on significant morphological differences. They range in length from about 200 to 850 μm. Nauplius 1 has a plumb and lecithotrophic appearance with a rounded hind body and a labrum with an incipient medial spine. Limb segmentation is mostly unclear but the second antennae have more putative segments delineated than are expressed in the later stages. Feeding structures such as the mandibular coxal process and antennal coxal spine are only weakly developed. Nauplius 2 is very different from nauplius 1 and has three large spines on the labral margin and two long caudal spines. Feeding structures such as the mandibular coxal process and various spines and setae are developed, but whether feeding begins at this stage was not determined. The mandible has developed an ‘extra’ seta on endopod segment 1, absent in Nauplius 1. The segmentation of the second antenna has changed significantly due to fusions of various early segments. Nauplius 3 is like nauplius 2 in morphological detail, but larger and more elongate. Nauplius 4 has developed a pair of small anlagen of the carapace and rudiments of the first five pairs of trunk limbs, and the coxal spine of the antenna has become distally bifid. Nauplius 5 has a larger carapace anlage, externally visible enditic portions of the elongate trunk limbs, and a pair of primordial dorsal telson setae. Nauplius 6 has a larger and partly free carapace and better-developed, partly free trunk limbs with incipient enditic, endopodal, and exopodal setation. A pair of caudal spines, dorsal to the large caudal spines, has appeared. Nauplius 7 is quite similar to nauplius 6 but is larger and has slightly longer caudal and labral spines; also, the setation of the most anterior trunks limbs is better developed. The larval development is largely similar to that of other spinicaudatans. The larval mandible, which is evolutionarily conservative within the Branchiopoda, reveals a setation pattern similar to that of the Anostraca and Notostraca (two setae on mandibular endopod segment 1). Most other spinicaudatans and all examined laevicaudatans share another setal pattern (one seta on mandibular endopod segment 1), which could indicate a close relationship among these taxa. The second antenna undergoes a special development, which provides an insight into the evolution of this limb within the Branchiopoda. In nauplius 1 the basipod, endopod, and exopod are all superficially divided into a relatively high number of segments. In later nauplii some of these have fused, forming fewer but larger segments. We suggest that this ontogeny reflects the evolution of antennae in the conchostracans. Various aspects of the morphology of the antennae are discussed as possible synapormorphies for either the Diplostraca or subgroups of the Conchostraca.     

Pneumonyssus africanus Fain, 1959 (Acari,Mesostigmata). Comparison of larva and adults with P. simicola Banks, 1901

Summary The lung mite P. africanus Fain, 1959 and its larva from a new host (Mandrillus leucophaeus) is described and compared to the most frequently found species, P. simicola Banks, 1901. The chaetotaxy of the legs is essentially identical, but leg IV of P. simicola bears 5 spines and 10 setae, while in P. africanus one of the spines is replaced by a seta. Also, very fragile small setae were discovered at the base of the ambulacra on legs II, III and IV in P. africanus and only on leg IV in P. simicola. The chaetae of the ‘Haller's organ’ on leg I are described in detail, and formulae for the chaetotaxy of all legs and measurements of both species are given. ac]19860213     

Acanthodiaptomus denticornis another omnivorous calanoid copepod: description of its mouth appendages and feeding experiments on animal prey

The mouthpart morphology of the freshwater calanoid copepod Acanthodiaptomus denticornis was examined with optical microscopy. The mouthparts have sharp teeth and stout appendages with clawlike setae, typical of omnivorous calanoid mouthpart morphology. Observation of the buccal aperture with Scanning Electron Microscopy shows a large opening permitting feeding on prey as large as Keratella cochlearis. These observations agree with our feeding experiments which show that A. denticornis feed on K. cochlearis.     

Intertidal interstitial Halicyclops from the Brazilian coast (Copepoda: Cyclopoida)

H. tageae sp. n. and Halicyclops ytororoma sp. n. are described from the intertidal interstitial water of Brazilian beaches. H. tageae is distinguished from all congeneric species by the number of setae on legs 1–4 endopodite 2 (1, 1, 2, 2) and by possessing a reduced inner spine on the leg 5 exopodite. It shares with H. brevispinosus, H. pusillus and H. canui the spine formula 2, 3, 3, 3 on exopodite 3 of swimming legs 1–4. H. ytororoma closely resembles H. gauldi and differs from this species by having 4 setae on leg 1 endopodite 3; H. gauldi has 3 setae on this segment.This is the first record of Halicyclops from marine interstitial water in Brazil.     

Description of a new species of deep-water crab of the genus Homolodromia A. Milne-Edwards, 1880 from the northern Indian Ocean (Crustacea: Decapoda: Brachyura: Homolodromiidae)

ABSTRACT

Homolodromia rajeevani, a new species of deep-water homolodromiid sponge crab, is described from the northern Indian Ocean (Arabian Sea, depth 957 m, and Bay of Bengal, 645 m), and is the first record of the genus from the area. This species resembles the western Indian Ocean species, namely, Homolodromia bouvieri Doflein, 1904, in having 2 terminal spines on the propodi of the last two pereopods, but can be easily distinguished from the latter species by the inflated carapace, simple long setae on carapace and appendages, slender pseudo-rostral spines separated by a U-shaped base, and a slender arched dactylus of cheliped with maximum elevation at proximal part which bears broadly circular depressions with sparse setae. The most diagnostic character is the higher number of spines on the occlusal surfaces of propodal thumbs and dactyli of the pseudochela of the last two pereopods as compared to H. bouvieri. A key for the identification of the species under the genus Homolodromia is also provided.

http://zoobank.org/urn:lsid:zoobank.org:pub:48894F49-5124-4723-9FF2-3D30FB536DA5     

A new species of <Emphasis Type="Italic">Eurycletodes</Emphasis> Sars, 1909 (Copepoda: Harpacticoida: Argestidae) from the southern hemisphere including remarks on the phylogeny of the genus and its subgenera

This paper deals with taxonomy and phylogenetics of the genus Eurycletodes Sars, 1909 (Copepoda: Harpacticoida: Argestidae). Samples, collected from the southeast Atlantic on board RV “Meteor” during the cruises DIVA-1 (M48/1) and DIVA-2 (M63/2), contain specimens of Eurycletodes. Eurycletodes is characterized as a monophylum by A1 segments III + IV fused, basal seta of md palp lost, exp of md palp reduced to 1 seta or completely lost. Similarly, the subgenera Eurycletodes (Eurycletodes) and Eurycletodes (Oligocletodes) are characterized as monophyletic by the loss of the inner seta on P1 exp2 (apomorphic to E. (E.)) and the absence of the inner seta on P5 endopodal lobe (apomorphic to E. (O.)). Eurycletodes profundus is renamed as E. (O.) profundus. Eurycletodes ephippiger is the only species of the genus without subgeneric designation. Eurycletodes (O.) diva sp. nov. is described. The new species differs from described species of the genus by a larger body size, P5 endopodal lobe only slightly protruding, last segment of A1 with 2 outer setae, furcal rami elongated between setae VII and IV. The occurrence of 2 specimens of Eurycletodes (O.) diva sp. nov. at 2 sites separated by the Walvis Ridge supports the hypothesis that geographic obstacles do not prevent harpacticoid copepods from spreading in the deep sea.     

A new species of Pseudomacrochiron Reddiah, 1969 (Crustacea: Copepoda: Macrochironidae) associated with scyphistomae of the moon jellyfish Aurelia sp. (Cnidaria: Scyphozoa) off Japan

A new species of the Macrochironidae Humes & Boxshall, 1996 (Copepoda: Cyclopoida), Pseudomacrochiron aureliae n. sp., is described based on adult specimens extracted from the gastrovacular cavity of the scyphistomae of Aurelia sp. (Cnidaria: Scyphozoa) collected in the Seto Inland Sea and Ise Bay off the coast of Japan. The new species differs from its congeners by having the following combination of characters: a caudal ramus with a length to width ratio of 3.1; an accessory flagellum on caudal setae II, III and VI; three apical setae on the maxillule; only setae I and II on the maxillary basis; two short spines on the female maxilliped claw (endopod); an armature of III, I, 4 on the terminal exopodal segment of leg 3; an armature of I, II, 2 on the terminal endopodal segment of leg 3; an armature of II, I, 4 on the terminal exopodal segment of leg 4; and a short free exopodal segment of leg 5 (length to width ratio of 1.4) armed with a long seta and short spine. P. aureliae n. sp. is the first member of the genus reported from off Japan and from the scyphistomae of its scyphozoan host.     

Grazing rates and behaviors of Neocalanus plumchrus: implications for phytoplankton control in the subarctic Pacific

Grazing rates and behaviors of the copepod Neocalanus plumchrus were investigated in shipboard experiments during the first SUPER Program cruise (May, 1984). N. plumchrus can exploit cells in the 2 to 30 m size range with equal clearance efficiency but displays considerable flexibility in responding to changes in concentration and size composition. Its functional response helps to stabilize phytoplankton at low densities. In 60-liter microcosms, a density of one copepod liter^–1 was sufficient to maintain the ambient abundance and structure of the phytoplankton community for a week. In the absence of the copepod, phytoplankton bloomed to unnaturally high levels, and the community composition was dramatically altered. Despite its grazing potential, N. plumchrus was not present in sufficient density to control phytoplankton blooms in the subarctic Pacific. However, the copepod may have an important role in regulating the abundance of smaller grazers and the size structure of the phytoplankton community.Contribution No. 2002 from Hawaii Institute of Geophysics, University of Hawaii, Honolulu, HI 96822     

A new species of Ceriodaphnia from Uzbekistan and Kazakhstan

A Ceriodaphnia has been found inWaterbodies of the plains and foothills of Uzbekistan and southern Kazakhstan that strongly resembles C. reticulata (Jurine, 1820). The female of this new species, C. turkestanica, differs from C. reticulata because it lacks a fenestra (nucal organ) in the cervical notch of the adult, has a rostral pore encircled by a ridge of cuticle rather than opening on the flat surface of a polygon anterior to the antennules, and has fewer and finer spines punctuating the row of fine spinules along the inner margin of the posterior carapace. The locule of the ephippium lacks the regular, small, rounded protuberances seen in the locule of C. reticulata. The male of C. turkestanica also exhibits the lack of a cervical fenestra, an encircled rostral pore, and variable, fine spines along the posterior carapace inner margin. In addition, it has a much shorter terminal seta on the antennule, and increasing lengths of the spinose setae on endites 1–3 of trunk limb I rather than the second being the longest as in C. reticulata. Because of similarities between these species, we suggest that C. turkestanica either is derived from C. reticulata or that the two share a common ancestor.     

Habrobathynella nagarjunai n. sp., the second representative of Bathynellacea (Crustacea, Syncarida) from groundwaters of South India

A new species of the genus Habrobathynella Schminke, 1973, i.e. H. nagarjunai n.sp., is described from the groundwater of the Nagarjuna University campus near Guntur town, South India. One of the principal criteria in the original definition of Habrobathynella is amended to accommodate the new species. H. nagarjunai n.sp. differs from its three congeners, i.e. H. milloti (Delamare & Paulian, 1954), H. jeanneli (Delamare & Paulian, 1954) from Madagascar, and H. schminkei Reddy, 2002 from India, in several essential morphological details: the sympodite of uropod bears 8–10 similar spines; the apophysis on segment 4 of the antennule is short; of the two setae on the exopodite of uropod, one is apical and the other subapical in position; the basal segment of maxilla has three unequal setae; the male thoracopod VIII is relatively elongate. H. nagarjunai n. sp. is the second representative of the groundwater (eustygobiont) Bathynellacea in South Asia. Furthermore, a key to the identification of Habrobathynella spp. is given.     

Late postnaupliar development of Monstrilla sp. (Copepoda: Monstrilloida), a protelean endoparasite of benthic polychaetes

Polychaete specimens from Hawaii were infected by the copepod Monstrilla. The development of these protelean parasites has remained unstudied for more than a century. Three postnaupliar endoparasitic stages were obtained: copepodids CIII, CIV, and CV, the latter stage found previous to and during emergence. Copepodid development, including the body and appendages (antennules, legs 1–4, caudal rami), is described and analyzed. The feeding tubes and the exiting from the host are also described. In light of the recently proposed inclusion of monstrilloids among caligiform copepods, it was found that monstrilloid copepodid development diverges from caligiforms and other copepod groups in: (1) the segmentation of the urosome at CIII, (2) the early formation of a genital complex, (3) early completion of swimming legs setation, at CIII; (4) delayed segmentation of rami of leg 3 at CIII (vs. the usual two-segmented pattern), (5) loss of one exopodal seta of leg 1 at CIV, (6) full development of leg 1 endopod vs. usually vestigial condition in caligiforms; (7) earlier segmentation of leg 4 rami, and (8) stable interstage (CIII–CV) setation pattern of legs 3 and 4. Overall, monstrilloid development appears to have unique characters and their phylogenetic relations deserve further study.