Description of the immature stages of Sigara (Tropocorixa) santiagiensis (Hungerford, 1928) (Insecta: Heteroptera: Corixidae)

The immature stages of Sigara santiagiensis are described and illustrated for the first time. The eggs of Sigara can be distinguished by the chorionic surface. The main characters separating the five nymphal instars of S. santiagiensis are: body and head lengths; body, head and eye widths; ocular index; numbers of transverse sulcations of the rostrum, setae on the inner surface of protibiotarsus, campaniform sensilla on posterior surface of protrochanter, spines on posteroventral surface of mesotibia and on tibial comb of metaleg, long, slender setae on posterodorsal surface of mesotarsus, spines and swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and grade of development of the wing pads. The body length, the chaetotaxy of the mesonotum, profemora and metafemora, protibiotarsus, metatibia, metatarsus and urosternites distinguish species or group of species of instars I and V of some of the species of the genus Sigara described up to now.     

Expanding the taxonomic conundrum: Three new species of groundwater crustacean (Syncarida,Bathynellacea, Parabathynellidae) endemic to the Iberian Peninsula

Two new species of the genus Iberobathynella and one new species of the cosmopolitan genus Hexabathynella are described from the Iberian Peninsula. The three new species were found in the groundwater of caves and the gravelly bank of a river, two species in the north of Spain (Cantabria and Burgos) and one in the south (Sevilla). The two new species of the genus Iberobathynella present a unique combination of characters. These character combinations for the species from Cantabria are: thoracopod 8 female with wrinkled cuticle and two teeth; seven spines on the furca; nine spines on the sympod, three barbed and one plumose seta on the exopod and two barbed setae on the endopod of the uropod; maxilla with 0, 0 and 15 setae on the three segments, respectively; five teeth on the pars incisiva and six teeth on the pars molaris of the mandible and seven segments on the antennule. The combinations of characters for the species from Burgos are: antennule with seven segments; segment 5 of the antennule with one aesthetasc; mandible with four and five teeth on the pars incisiva and pars molaris respectively; maxillule with one seta on segment 1 and 14 setae on segment 3; segment 1 of the endopod of the thoracopod 1 with two setae; uropod with six spines on the sympod, four barbed setae and one plumose seta on the exopod and no setae on the endopod; furca with five spines and the thoracopod 8 female with wrinkled cuticle and two teeth. This last species has an exclusive character for the genus: the absence of setae on the endopod of the uropod. The new species of the genus Hexabathynella has six spines of similar length on the sympod of the uropod (in all other species within the genus the distal spine is longer than the others); the form of the antennal organ in the males is shown to be a new unique character for the genus; the maxilla has three and 13 setae on segments 2 and 3, respectively; the uropod has six spines on the sympod, three barbed setae on the exopod and two smooth setae on the endopod, the endopod is twice as long as the exopod and the shape of the female thoracopod 8 is unique.     

A new species of Halolaelapidae (Acari: Mesostigmata: Rhodacaroidea) from beach wrack in Yaquina Bay,Oregon, USA,with comments on opisthonotal plasticity and cribral development in the family

Decomposing beach wrack in a backwater of Yaquina Bay, Oregon, was found to contain nymphs and adults of a previously undescribed species of the mite genus Halolaelaps (Halolaelapidae). Significant variation was noted among available specimens in the number of opisthonotal shield setae, a feature that has long been considered to be of critical importance in identifying celticus group species. The presence of a well-formed posterodorsal cribrum in this and related celticus group species prompted an examination of cribral development in the Halolaelapidae as a whole and revealed that posterodorsal cribral elements occur in various configurations in three of the four presently recognized halolaelapid genera. A narrow, transversely oriented configuration appears to be unique to members of the celticus species group.     

Disentangling an Asian puzzle: Two new bathynellid (Crustacea,Syncarida, Parabathynellidae) genera from Vietnam

In this paper the 17 asiatic species of the family Parabathynellidae are reviewed from a taxonomic point of view using bibliographic data. Two new genera and two new species are described from caves in Vietnam. Paraeobathynella n. g. presents a unique combination of characters (antennule: seven segments; antenna: six segments; mandible: pars incisiva with five teeth and pars molaris with 10 teeth; maxillule: distal endite with seven claws; exopod of the thoracopods with three or more segments and epipods present in thoracopods 3–7; pleopods absent; endopod of the Th 8 male with two setae; seven spines on the sympod and two spines on the endopod of the uropod and the small minimum size of the adult body) and exclusive characters like the Th 8 female having two small spines and one long seta and the general size and aspect of the Th 8 male and its lobes. Sketinella n. g. presents a unique combination of characters (antennule: eight segments; antenna; six segments; mandible: pars incisiva with six teeth and pars molaris with eight teeth: maxillule: distal endite with seven claws; exopod of the thoracopods with three or more segments and epipods present in Th 3–7; endopod of the thoracopod 8 male with two setae; 12 spines on the sympod and two spines on the endopod and seven setae on the exopod of the uropod) and characters exclusive to the asiatic species are: a pair of pleopods reduced to a single seta; a very distinctive basipod and outer lobe of the Th 8 male and an exopod of the Th 8 male with a small tooth or protuberance. This is the first time that the Parabathynellidae has been found in Vietnam, this find extends the range of distribution of this family in Asia.     

Thalassarachna and Halacarellus (Halacaridae: Acari): two separate genera

During the last half century, the generic names Halacarellus and Thalassarachna have been used in parallel. The author now proposes to regard them as two separate genera distinguished by the number of dorsal setae on tarsi I and II. Halacarellus s. str., with Halacarus balticus Lohmann as the type species, has three dorsal setae on both tarsi, whilst Thalassarachna s. str., with the type species Acarus basteri Johnston, has five or more dorsal setae on tarsus I and four or more on tarsus II. The number of setae on tarsi I and II is expected to be a valid generic character. Species of the genus Halacarellus s. str. are recorded from both the northern and southern hemispheres; the North Atlantic species are distinct from those in the southern oceans. Thalassarachna s. str. is known only from the North.     

New species of Brodskius,Rythabis, and Omorius (Crustacea: Calanoida) from deep Antarctic waters

Three new species of rare benthopelagic clausocalanoidean genera with sensory setae on the maxilla are described from female specimens collected during the German Antarctic expeditions ANDEEP I–III in 2002 and 2005, mainly from abyssal depths close to the sea bed. Brodskius abyssalis sp. nov. differs from congeners by the lack of rostral filaments, two setae on the second segment of antenna exopod, thread‐like tips of maxillary worm‐like sensory setae, and the length of spines of P5 exopod. Rythabis assymmetrica sp. nov. is distinguished from other species in the genus by asymmetrical posterior corners of the prosome, the shape of spermathecae, and setal numbers on the maxillulary distal basal endite plus endopod. Omorius curvispinus sp. nov. is characterized by strongly curved setae of the maxillipedal syncoxa, a comparatively long seta on the basis of antenna, a slightly swollen genital double‐somite, and the shape of spermathecae. The genera Brodskius, Omorius, and Rythabis are recorded for the first time from the southern hemisphere.     

A new genus for Acanthomysis schrencki (Czerniavsky, 1882) (Crustacea: Mysida: Mysidae) with the first description of the male

A new genus, Boreoacanthomysis, is established for the reception of Acanthomysis schrencki. The new genus is characterized by the fourth male pleopod armed with a pair of long plumose setae at the distal end of the proximal segment of the exopod, and by the uropodal endopod armed with about 30 spines near the statocyst. The male of this species is described for the first time.     

First record of the genus Atlantistylis Reyss, 1975 (Crustacea: Cumacea) from the North Atlantic,with the description of a new species

A new species of the genus Atlantistylis Reyss, (Diastylidae) is described from the Atlantic Frontier Margin (North‐East Atlantic). This is the first record of the genus Atlantistylis from the North Atlantic. The new species Atlantistylis borealis can be recognized by the presence of spines on the frontal and lateral lobes of the carapace combined with their absence on the pereon and pleon; the first pereopods are very long. The small telson with two small apical acuminate setae and the absence of pleopods in the male are characteristic of the genus.     

On three new species of Mesochra Boeck, 1865 (Harpacticoida: Canthocamptidae) from Iceland

Three new species of Mesochra Boeck, 1865, were found during two surveys in south‐western Iceland of the feeding ecology of juvenile lumpsucker Cyclopterus lumpus Linnaeus, 1758, in floating seaweed and the seasonality of harpacticoids in a low intertidal pool. Only two species of the genus, M. lilljeborgi Boeck, 1864 and M. rapiens (Schmeil, 1894), have been found in previous studies in Iceland. The three new species, Mesochra ingolfssoni sp. nov., Mesochra snoppa sp. nov., and Mesochra freyri sp. nov. resemble M. stellfeldi Jakobi, 1954 in the normal (not dwarfed) outer seta of both male and female P5 EXP, but differ in that M. stellfeldi possesses unequal inner baseoendopodal setae on the female P5. The three new species resemble M. pygmaea (Claus, 1863) in the equal inner baseoendopodal setae of the female P5, but differ in the dwarfed outer seta of the male and female P5 EXP present in M. pygmaea, and can be easily separated by shape of the rostrum, female P6, number of pinnate elements on the second antennular segment, general shape of the antenna and shape of the lateral and distal inner spines, among other character states.     

The first record of Syncarida in Montana,USA: a new genus and species of Parabathynellidae (Crustacea,Bathynellacea) in North America

Montanabathynella salish gen. nov. sp. nov., of the family Parabathynellidae, from Montana, USA, is described. The new species displays several exclusive characters: distal endite of the maxillule with nine claws and a very large and distinctive male thoracopod 8 with four lobes in the basal penial region and a long recurved exopod without setation. It also presents a unique combination of characters: antennule seven‐segmented; antenna six‐segmented; labrum with 18 teeth; exopod of thoracopods three‐ to six‐segmented, endopod with one dorsal seta on the first and second segments and epipod only present on thoracopods 4 to 7; pleopods absent; endopod of thoracopod 8 male with two setae and exopod without setae; female thoracopod 8 having two segments, first segment with two groups of denticles and the second one with three long barbed setae; 15 spines on sympod, four spines and spinous process on endopod and 12 setae on exopod of uropod.     

A new genus of Parabathynellidae (Crustacea: Bathynellacea) in New South Wales,Australia

A new genus and species of the family Parabathynellidae, Octobathynella peelensis gen. nov. sp. nov., is described from New South Wales, Australia. The new genus displays several exclusive characters: a very large and distinctive male thoracopod VIII with one crest-like projection containing two lobules on the basipod; and four aesthetascs on segments six and seven of the antennule. It also has several combinations of characters that make it unique in the Parabathynellidae, specifically that: the antennule is eight-segmented (a new character in the Australian species); there are seven segments in the antenna; the labrum has 18–20 teeth; the exopod of thoracopod I has three to four segments and the exopod of thoracopod II has four segments; the endopod has one dorsal seta on the first and second segments and the epipod is absent on thoracopod I; pleopods are absent; the endopod of the male thoracopod VIII has two setae and the exopod has setules; there are 10–12 spines on the sympod, three or four spines on the endopod and five setae on the exopod of the uropod. The new genus and species is placed into context with all known Bathynellacea in Australia, and the biogeographic patterns are discussed for this ancient group of subterranean crustaceans.     

New deep-sea Poecilochaetidae (Polychaeta: Spionida) from New Zealand

Three Poecilochaetus species occurring in N.Z. waters are described. Poecilochaetus trachyderma n. sp. is similar to P. fulgoris Claparède; P. aff. bermudensis Hartman and P. sp. 3 are previously unrecorded species, but as yet only anterior fragments have been obtained. Setal microstructures were examined by scanning electron microscopy. P. trachyderma and P. aff. bermudensis have distinctive capillary setae with nested spiral palisades of fused spinules. P. aff. bermudensis has hispidpappose capillaries with twin accessory spines. A key to the family is given.     

Paranannopidae (Copepoda: Harpacticoida) from sublittoral soft sediments in Spitsbergen

Based on specimens of Paranannopidae collected from 30 to 123 m depth in Sassenfjord, Spitsbergen, two species of Paradanielssenia Soyer, 1970 (P. christineae sp. nov. and P. kathleenae sp. nov.) are described. These can be distinguished from known species by differences in the number of claviform aesthetascs on the mouthparts and in the arrangement or form of setae on the legs. A key to species of Paradanielssenia is provided. Mucrosenia gen. nov. (type species M. kendalli sp. nov.) is established on the basis of a single female and can be distinguished from all known paranannopid genera by the structure of the caudal ramus and the P2 endopod-2 which has no inner seta and a large mucroniform process at the outer distal corner. Psammis kliei Smirnov, 1946 is assigned to this genus as species incertae sedis. Danielssenia quadriseta Gee, 1988 is recorded for the first time outside its type locality in Oslofjord. Danielssenia spitsbergensis sp. nov. is described from a single male specimen and can easily be distinguished from other known species by the presence of only two outer spines on exopod-3 of P3-4. However, because of differences in the structure of the P2 endopod and P5, the species is placed incertae sedis within Danielssenia pending the discovery of the female.     

Two new species of Siphonostomatoida (Copepoda) found on cnidarians in Tokara Islands,Southern Japan

ABSTRACT

Two new species of siphonostomatoid copepods are described based on specimens collected off Tokara Islands located in the northern part of the Ryukyu Islands, Southern Japan. Cholomyzon multisetum sp. nov. (Coralliomyzontidae) found from the orange cup coral Tubastraea coccinea Lesson, 1829 (Hexacorallia: Scleractinia: Dendrophylliidae) has the following characters: armature formula of the antennule of the female; the outer lobe of the maxillule; and numbers of elements on the legs 1 to 3. Another species, Entomopsyllus takara sp. nov. (Entomolepididae), was found from both the Indo-Pacific blue coral Heliopora coerulea (Pallas, 1766) (Octocorallia: Helioporacea: Helioporidae) and the race coral Distichopora violacea (Pallas, 1766) (Hydrozoa: Anthoathecata: Stylasteridae). This new species of the male specimen is characterized by the antennule with shortest sixth segment, the endopod of leg 2 bearing two inner setae on the second segment and five setae on the third segment, the third exopodal and endopodal segments of leg 3 bearing three spines and three setae, respectively, and the third exopodal segment of leg 4 bearing four setae. These two species represented the first records of the families Coralliomyzontidae and Entomolepididae from Japanese waters.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:7C8DED0A-9CEB-405D-9BBF-FAF2043B0858     

The larval development of Argulus coregoni Thorell (Crustacea: Branchiura)

Summary

The larval development of Argulus coregoni from the first to the ninth stage was studied, with special reference to the morphological changes of the appendages and some other parts of the body.

A newly hatched larva is a copepodid-form measuring 0·6–0·7 mm long and approaches the shape of the adult after moulting into the second stage (0·7–0·9 mm). Throughout the larval stages, the first maxilla shows the most remarkable modification. The larvae of the first to the fifth stage are equipped with two strong, curved claws, which act as a clasping organ, at the terminal segment of the first maxilla. The basal segment expands considerably at the third stage (0·9–1·1 mm) prior to forming a sucker at the sixth stage (1·7–2·2 mm). The claws start to degenerate at the fifth stage (1·4–1·8 mm), but are still recognizable as a rudiment after the seventh stage (2·2–2·6 mm). The other distinct morphological changes that occurred are: (1) bifurcation of the anterior part of the dorsal ridges on the carapace, (2) development of the male accessory copulatory organ at the basal segments of the second to the fourth legs, (3) number of posteriorly directed minute spines on the ventral surface of the carapace, (4) number of elements in the supporting ribs of the suckers, (5) number of spines found at the first segment of the second maxilla, and (6) number of setae on the four pairs of thoracic legs.

The larval forms of A. coregoni younger than the fourth stage (1·1–1·4 mm) are indistinguishable from those of A. japonicus and A. foliaceus.     

On the northernmost Ajmonia Caporiacco, 1934 (Aranei: Dictynidae: Dictyninae)

Ontogeny of loss of gastronotal setae in Arthrodamaeus reticulatus (Berlese, 1910), Gymnodamaeus bicostatus (C.L. Koch, 1836) and Jacotella neonominata Subías, 2004 Subías, LS. 2004. Listado sistemático, sinonímico y biogeográfico de los Ácaros Oribátidos (Acariformes, Oribatida) del mundo (1748-2002). Graellsia., 60: 3–305. [Crossref] , [Google Scholar] was investigated. From the larval setation, the protonymph of these species loses three pairs of d-series and two pairs of l-series; these losses continue through subsequent nymphal stages and adult. Between tritonymph and adult, setae of h-series are subject to loss; A. reticulatus loses none, G. bicostatus loses one pair (h ₃) and J. neonominata loses two pairs (h ₂ and h ₃). The nymphs of these species bear the gastronotic exuviae of previous instars, but they differ in the appearance of the exuviae, the manner of their connection with the gastronotum, and the shape of setae c ₃ and lp, which in some species helps secure the exuviae to the body. Other aspects of ontogeny of these species are described and illustrated for the first time, and morphological characters that distinguish Arthrodamaeus, Gymnodamaeus and Jacotella are discussed.     

Systematic status of Hydrozetes octosetosus Willmann, 1932 (Acari: Oribatida: Hydrozetidae) in the light of ontogenetic and ecological studies

The systematic status of Hydrozetes octosetosus was investigated by comparing this species to H. lacustris, which is the type species for the genus Hydrozetes Berlese, 1902. These species are similar, but probably not synonyms as recently proposed. They differ mainly by the position of notogastral seta lm in the adult and position and length of this seta and total number of long setae in the posterior part of nymphs. In the adult of H. octosetosus, this seta inserts behind the opisthosomal gland opening (gla), but in front of it in H. lacustris. In the nymphs of H. octosetosus seta lm inserts behind gla opening, but medially to it in H. lacustris. In H. octosetosus this seta is very long and the total number of long setae in nymphs is four pairs, while in H. lacustris seta lm is short and the total number of long setae in nymphs is three pairs.