Third Endopodal Segment Of Leg Research Articles

Description of Barathricolathermophilus, a new species from a deep-sea hydrothermal vent field in the Indian Ocean with redescription of the Barathricola type species (Crustacea, Copepoda, Cyclopoida).

Re-study of the type species of the genus Barathricola Humes, 1999 (Copepoda, Cyclopoida, Schminkepinellidae) described from the Pacific Ocean (Juan de Fuca Ridge), and study of the species Barathricolathermophilussp. nov. from a deep-sea hydrothermal vent field on the Central Ridge in the Indian Ocean revealed a derived feature and widespread geographic distribution of this deep-sea genus of cyclopoids. The derived feature of Barathricola is the sexually dimorphic third endopodal segment of leg 3 possessing a small outer terminal spine together with spine-like outgrowths on this segment. The new species differs from Barathricolarimensis Humes, 1999 in not expressing sexual dimorphism in leg 5, having three spines and one seta on its exopod in both sexes (B.rimensis has three spines and one seta on the female exopod but three spines and two setae on the male exopod) and in having broader caudal rami which are 8.9 times longer than wide in the female (this ratio for B.rimensis is 11). An amended diagnosis of the genus Barathricola, a key and a table of morphological differences for all species of Schminkepinellidae are given.

A new species of Hamaticolax (Copepoda: Bomolochidae) from Helicolenus dactylopterus (Delaroche, 1809) (Scorpaeniformes: Sebastidae) in NW Mediterranean deep waters and notes on patterns of host use and host-specificity of the genus.

Hamaticolax juanji n. sp. is described from specimens collected from the blackbelly rosefish Helicolenus dactylopterus Delaroche 1809 (Scorpaeniformes: Sebastidae). It is the second Hamaticolax species described and reported from the Mediterranean Sea, after Ha. resupinus Pérez-i-García, Carrassón and Boxshall, 2017. It is distinguished from Ha. resupinus by the presence of only one dorsal naked seta on the third segment of the antennule (vs. four), two unequal short naked setae in distal part of the antenna (vs. four), and the absence of a minute spine on the third endopodal segment of leg 1, among others. It is differentiated from Ha. prolixus Cressey 1969 by a comparatively reduced fourth pedigerous somite, the presence of two naked setae on the third segment of the antennule (vs. three), two naked setae and three curved claws in the distal part of the apical segment of the antenna (vs. three and four), an outer naked seta on the basis of leg 2, and by larger length/width ratio of the third endopodal segment, among others. Hamaticolax juanji n. sp. also has relatively longer inner setae on the first and second endopodal segments of leg 4 than the two former species. Patterns of host-use and host-specificity of the genus Hamaticolax are also discussed. The frequently observed low host-specificity of its members may be better explained by host ecological similarity and host availability phenomena, rather than by host phylogenetic distance.

A new marine cyclopoid copepod of the genus Neocyclops (Cyclopidae, Halicyclopinae) from Korea.

A new cyclopoid species of the genus Neocyclops Gurney, 1927 is described. Type specimens were collected from a beach on south-western coast of the Korean Peninsula by rinsing intertidal coarse sandy sediments. Neocyclops hoonsooi sp. n. is most characteristic in showing the conspicuous chitinized transverse ridges originating from the medial margins of the coxae of all swimming legs. The new species is most similar to Neocyclops vicinus, described from the Brazilian coast, and Neocyclops petkovskii, from Australia. All three species share a large body size (more than 750 µm long), the presence of an exopodal seta on the antenna, two setae on the mandibular palp, the same seta/spine armature on the third endopodal segment of leg 3 (3 setae + 3 spines), and the fairly long inner distal spine on the third endopodal segment of the female leg 4. However, Neocyclops hoonsooi sp. n. differs from both species by the much shorter caudal rami (less than 1.7 times as long as wide) and the shorter dorsal caudal seta VII. Furthermore, Neocyclops hoonsooi is clearly distinguished from Neocyclops vicinus by the 10-segmented antennule (vs 12 segments in Neocyclops vicinus), and from Neocyclops petkovskii by the elongate inner distal spine on leg 5 exopod and the 3-segmented leg 5 in male (vs 4-segmented in Neocyclops petkovskii). A tabular comparison of characters separating Neocyclops hoonsooi from its closest allies and a key to Neocyclops species from the Indo-Pacific Ocean are provided. This is the first record of the genus Neocyclops from the northern Pacific.

Two new species of asterocherid (Copepoda: Siphonostomatoida) associated with a sponge from the Strait of Messina, Italy: taxonomic and ecological traits

Two new species of asterocherid associated with sponges are described from the Mediterranean Sea. They are Psilomyzon laetitiae sp. nov. and Psilomyzon sarcotragusicola sp. nov. The genus Psilomyzon consists of only one known species, P. pauciseta. The two new species can be easily distinguished from the cogener species by reduction of the endopod of leg 4. In P. pauciseta the leg 4 endopod is 3-segmented, with the third segment reduced; in both new species it is 2-segmented, with the second segment carrying an inner projection, possibly homologous to the third segment of the leg 4 endopod of P. pauciseta. In the two new species, the bifid outer process on male leg 4 second endopodal segment seems to be serially homologous to the similar processes on the same segment in legs 1–3, whereas the inner projection may represent a vestigial element of the third endopodal segment of leg 4.http://zoobank.org/urn:lsid:zoobank.org:pub:33BF0653-BBA9-426B-B365-5D8C62DFD44A

Three artotrogids (Crustacea: Copepoda: Siphonostomatoida) from the Ross Sea, Antarctica

The Artotrogidae, one of the most primitive of siphonostomatoid families, consists currently of 117 species in 21 genera. Most of these species (65%) are poorly or incompletely described since they have been rarely recorded in recent decades and, when encountered, have been found in very low numbers. During the 19th Italian Antarctic Expedition, with the RV Italica, to the Ross Sea in austral summer 2004, some artotrogid copepods were collected. This paper redescribes two species of artotrogid copepods, which are known only from the Southern Ocean, Neobradypontius neglectus and Cryptopontiuslatus, and describes for the first time a male of the genus Neobradypontius. Furthermore, a new species is described and added to Sestropontius, increasing the number of known species of this genus to three. The main discrepancies between the original descriptions and the specimens of the two species collected from the Ross Sea redescribed here were on the armature of the antennary exopod and leg 5. The new species, Sestropontius italicae, shares with its most similar congener, S. mckinnoni, the armature of the third endopodal segment of leg 1 and leg 2 and that of the third exopodal segment of leg 4. However, the segmentation of the antennae and the armature on the antennary exopod are different.Keywords: Antarctica; Artotrogidae; redescription; Neobradypontius; Sestropontius; CryptopontiusTo access larger versions of Figs. 2–12 please see the supplementary file in the column to the right (under Article Tools)(Published: 8 December 2014)Citation: Polar Research 2014, 33, 24135, http://dx.doi.org/10.3402/polar.v33.24135

Three species ofAsterocheres(Copepoda: Siphonostomatoida: Asterocheridae) from shallow Antarctic water

Three species ofAsterocheres, including two new species, are reported as associates of sponges in shallow Antarctic water.Asterocheres spinosussp. nov. has a combination of diagnostic features: mandibular palp is one-segmented, caudal ramus is 1.88 times as long as wide, antennule is 20-segmented in the female and 18-segmented in the male, urosome is spinulose, and legs 1 and 2 display weak sexual dimorphsims. InA. raisp. nov., the body is large, 1.66 mm long in the female, the lateral margin of genital double-somite is smooth without setules or spinules, the exopod of antenna bears only a single seta, with two mucilaginous substances transformed from setae, and the third endopodal segment of leg 1 bears a prolonged distal process. A supplementary description is given forA. hirsutusBandera, Conradi and López-González, 2005, recorded previously from the Antarctic.

Two new species of Halicyclops (Copepoda, Cyclopoida) from the estuarine interstitial waters in South Korea

Two new cyclopoid species belonging to the genus Halicyclops Norman, 1903 are described from brackish waters in South Korea: H. lanceolatus sp. nov. and H. pumilus sp. nov. Halicyclops lanceolatus was collected from two river mouths, both connected to caves. It belongs to the thermophilus group in showing 3,4,4,3 spine formula on legs 1-4 and lateral process on the genital double-somite. Among the members of the species group, it is closely allied with H. thermophilus Kiefer, 1929 and H. uncus Ueda and Nagai, 2009. However, it differs from them by a stout, lanceolate inner apical spine on leg 5 exopod, very short lateral process of the genital double-somite, short caudal rami, and shorter inner apical spine on the third endopodal segment of leg 4. Halicyclops pumilus was collected from interstitial waters of estuarine sandy beaches, and it is characteristic in having a single inner seta on the second endopodal segments of legs 2-3, and quadrate shape of leg 5 exopod with stumpy spines.

Two new species of harpacticoid copepods from anchialine caves in karst area of North Vietnam

Two new harpacticoid species belonging to the genera Microarthridion Lang, 1944 (Tachidiidae) and Nitocra Boeck, 1864 (Ameiridae) are recorded from underground caves in the karst area of Ninh Binh Province, North Vietnam. Microarthridion thanhi n. sp. is distinguished from congeneric species by the number of setae on the antennary exopod, the structure of leg 5 in both sexes, and the finger-like process modified from an outer distal pinnate seta of the third endopodal segment of leg 2 in the male. Nitocra vietnamensis n. sp. has the character combination of six setae on the ellipsoidal exopod of leg 5 in both sexes, the first endopodal segment of leg 1 shorter than the whole exopod, the seta/spine armature of an inner seta of P2-P4 enp-1 and four elements on P2 enp-3, and the reduction of the proximal endite to a seta on the maxillary syncoxa.

Two New Species of Halicyclops (Crustacea: Copepoda: Cyclopidae) from Honshu with a Key to the Species of the Genus in Japan

Two new species of cyclopoid copepod, Halicyclops setiformis and H. itohi, are described based on female specimens from the Tama River estuary in Tokyo Bay, central Japan. One of the defining characteristics of H. setiformis is the presence of a setiform lateral element on the third exopodal segment of legs 3 and 4. Among its congeners, only H. blachei Lindberg, 1952 has similar elements; H. setiformis differs from it in the shape of the third endopodal segment of leg 4. This new species is considered carnivorous based on the occurrence of a specimen biting a nematode and the presence of stout, claw-like spines on the oral appendages. The second new species, Halicyclops itohi, is distinguishable from most of its congeners in the absence of lateral protuberances on the genital double-somite, the absence of a terminal accessory seta on the caudal ramus, and a 3.4.4.3 spine formula on the third exopodal segment of legs 1-4. Congeners sharing these three morphological characteristics differ variously from H. itohi in their caudal ramus shape, urosomal frills, antennal setal number, medial elements of the third endopodal segment of leg 4, and/or the shape of leg 5. The hitherto known Halicyclops species from Japan are briefly reviewed, and a key to the Japanese species is presented to resolve previous questionable identifications.

Giardella ricoensis n. sp. from the West Indies and the Proposal of the New Genus Goodingius (Copepoda: Cyclopoida: Clausidiidae)

A new genus Goodingius is proposed to incorporate Hemicyclops adhaerens(Williams), H. arenicolae Gooding, H. elongatus Wilson and H. subadhaerens Gooding, all of which bear the six-segmented female urosome, three mandibular elements (or three elements plus one rudimentary setule), five setae on the first antennular segment, and no inner coxal seta of leg 4. The genus Giardella Canu, a sister taxon of Goodingius, is redefined as possessing eight elements on the third exopodal segment of leg 3, only a single inner seta on the second endopodal segment of leg 4, four spines on the third endopodal segment of leg 4. To the genus Giardella, Hemicyclops caissarum Kihara and Rocha and H. carinifer Humes are assigned, in addition to Giardella ricoensis n. sp., Giardella callianassae Canu, and G. thompsoni A. Scott. Keys to the species of both genera are provided.

Acanthocyclops fonticulus(cyclopoida, cyclopidae), a new species of cyclopoid copepods from mountain springs in Korea

A new cyclopoid species belonging to the genus Acanthocyclops is described from several mountain springs in South Korea. This species is allied to A. kieferi species group in sharing 11-segmented antennules, but is, clearly distinguished from them by its single apical spine on the third endopodal segment of leg 4 and an extra spine on the distal segment of leg 5 in both sexes.

Poecilostomatoid copepods (rhynchomolgidae) associated with sea anemones (actiniaria) from Korea

Abstract Lichomolgus panikkari Gnanamuthu, 1955 (= Indomolgus panikkari), an incompletely known species, is redescribed based on a male specimen found newly from the Yellow Sea. A new genus of copepods, Lutumidomus, is proposed to incorporate Lichomolgus panikkari, Notoxynus tertius Kim, 2000, and Lutumidomus parvus n. sp., all associated with sea anemones. The new genus is differentiated from the related genera by a combination of characters that the antenna is 4‐segmented, with a claw and an enlarged seta in addition to other setae on the fourth segment, the third endopodal segment of leg 3 is armed with two spines and two setae, the second endopodal segment of leg 4 is armed with two spines and three setae, and the maxillule is armed with two terminal setae. Paramolgus nudipes n. sp. and Verutipes scutatus n. sp. are also described as associates of sea anemones from Korean seas.

New Erebonasteridae (Copepoda) from Vilkitzky Strait in the Arctic and from a Pacific Hydrothermal Vent Site (Northern Fiji Basin)

A new genus of the poecilostomatoid family Erebonasteridae is described from Vilkitzky Strait in the Arctic, the channel connecting the Kara Sea and the Laptev Sea. Within the Erebonasteridae, Nansennaster, new genus, belongs to the Centobnaster-group. The new genus is characterized by the presence of only 2 setae on the mandibular palp, the fusion of the second and third antennal segments, the presence of a single copulatory pore, and the relatively short furca lacking seta I. A previously overlooked sexual dimorphism in Centobnaster is described, the males of this genus having a modified outer spine on the third endopodal segment of leg 3. Amphicrossus tuerkayi, new species, is described from a deep-sea hydrothermal vent site in the northern Fiji basin. The new species has retained some remarkable plesiomorphic characters, such as an incompletely fused genital double-somite in the female, and 2 setae representing the endopod of the maxilla. An identification key to all known genera and species of the Erebonasteridae is provided.