P5 Exopod Research Articles

First record of the family Rhizotrichidae (Copepoda, Harpacticoida) from Turkey with description of a new species

Both sexes of Tryphoema gallipoliensis sp. nov. (Copepoda, Harpacticoida, Rhizotrichidae), collected from the Gulf of Saros (Turkey), are described. Specimens were collected from Kavakkoy beach, Canakkale province. The new species can be distinguished from other members of the genus by the setal arrangement of the swimming legs, by having lanceolate spinulose apical spines on the distal exopod segment of P3 and P4, and by having four spines on both the baseoendopod and the exopod of female P5. With this study, the sexually dimorphic swimming legs are reported for the first time in the genus Tryphoema as well as in the family Rhizotrichidae. Furthermore, the family Rhizotrichidae was recorded for the first time on the Turkish coasts.

On some new species of Ancorabolidae Sars, 1909 from the Gulf of California: the genera Ceratonotus Sars, 1909, and Dendropsyllus Conroy-Dalton, 2003 (Crustacea, Copepoda, Harpacticoida).

Two new species of two genera of the family Ancorabolidae, Ceratonotus elongatus sp. n. and Dendropsyllus californiensis sp. n., found at 1642 m and 1759 m depth, respectively, in the Southern Trough of Guaymas Basin, are described. Ceratonotus elongatus sp. n. was attributed to that genus by a series of character states of which the lack of dendroid dorsal processes on the P6-bearing somite and the presence of such processes on the first abdominal somite were definitive. This species was observed to be very close to Ceratonotus thistlei Conroy-Dalton, 2003 from the San Diego Trough, and can be separated by a number of traits of which the elongated sensilla-bearing dorsal tubercles on the second abdominal somite in the new species was definitive. Dendropsyllus californiensis sp. n. has been placed within that genus given the presence of four geniculate setae on P1EXP2 and one seta on P1ENP2, one inner seta on P3EXP3, and lack of inner armature on P4EXP3. Dendropsyllus californiensis sp. n. appears to be more closely related to Dendropsyllus thomasi Conroy-Dalton, 2003 and Dendropsyllus magellanicus (George & Schminke, 1998) on account of the spinulose nature of the basis of the maxilliped, the two-segmented P4ENP, and the fused condition of the P5 baseoendopod and exopod, and seems to be even more closely related to Dendropsyllus thomasi by the degree of development of the lateroventral processes of the cephalothorax. Dendropsyllus californiensis sp. n. can be separated from its congeners by the relative length of the first antennulary segment, relative length of the caudal rami, and by the armature formula of P3ENP2.

A new species of the genus Typhlamphiascus (Copepoda, Harpacticoida, Miraciidae) from the South China Sea

A new species, Typhlamphiascus tuerkayi sp. nov. (Copepoda, Harpacticoida, Miraciiidae), is described from specimens collected in the South China Sea. This new species differs from its congeners by the combined characters of the number of chitinous lamellae on the male P1, the apomorphic setal formulae of the swimming legs, and the setal number on P5. The new species is most similar to T. ovale Wells & Rao, 1987 and T. higginsi Chullasorn, 2009. It differs from the latter two species by the following features: the caudal ramus about three times as long as broad, P2 exp-3 with three outer spines, P3 enp-3 with two inner setae, P5 basoendopod in the female with four setae, P5 exopod in the female about three times as long as its greatest width, antennule of male 9-segmented, the inner edge of the basis in male P1 with eight chitinous lamellae, P5 exopod in male with four setae.

A new species of Strongylacron (Copepoda, Harpacticoida, Cletodidae) from intertidal mudflats in the Korean peninsula.

A new species, Strongylacron glabrum sp. n. is described from intertidal mudflats in the Korean peninsula. The new species is assigned to the monospecific genus Strongylacron Gee & Huys, 1996 in accordance with the generic morphological features of the rostrum, antennary exopod, and thoracic legs. However, Strongylacron glabrum sp. n. is clearly distinguished from the type species, Strongylacron buchholtzi (Boeck, 1873), by the naked anterior margin of rostrum, the elongate exopod and endopodal lobe of female P5 approximately 3.5 and 2.7 times as long as width, respectively, and the presence of 8–10 rod-like projections on prosomites. The genus Strongylacron is first recorded from Korean waters by the present study.

A new species of the genus Nannopus (Copepoda, Harpacticoida, Nannopodidae) from the mudflat of Ganghwa Island, Korea

Abstract During a study of the harpacticoid copepods from the intertidal mudflat of Ganghwa Island, in the Yellow Sea of Korea, a new species of the genus Nannopus was discovered. Nannopus ganghwaensis shared the character of seven elements in P4 exp-3 with N. flexibilis Lilljeborg, 1902, N. didelphis Fiers & Kotwicki, 2013, and N. hirsutus Fiers & Kotwicki, 2013. However, the new species was clearly distinguished from the three congeners by the combination of the following character states: (1) absence of the integumental window on the dorsal surface of cephalothorax, (2) the lateral margins of urosomites is not densely hirsute, (3) the distal small seta of P4 endopod is naked, (4) the innermost seta of P5 exopod fused to the segment, (5) the inner most distal seta of P2 enp-2 is 1.7 times longer than the outer spine of its segment, and (6) caudal seta IV slightly inflated at its insertion site, and pinnate. Additionally, the male of new species differed from N. didelphis by the following characters: (1)...

Development of an interactive identification key for Oncaeidae (Copepoda: Cyclopoida)

The current state of development of an interactive electronic identification key for females of the marine pelagic microcopepod family Oncaeidae is presented. To date, 112 species have been described, allocated to seven genera (Archioncaea, Conaea, Epicalymma, Monothula, Oncaea s.str., Spinoncaea, and Triconia) and 16 species groups within the speciose paraphyletic taxon Oncaea s.l. Only two species of Oncaea s.l. show an uncertain group status. Of all described oncaeids, seven species are not yet included in the key due to inadequacies in morphological description and/or lack of type material for re-examination. In addition, seven morphologically distinct species and two new species groups are considered that have not yet been formally described. The key uses easily distinguishable morphological characters as far as possible (e.g. body size, proportional lengths of urosomites, length of P5 exopod) and includes more difficult characters (e.g. spine counts on swimming legs, proportional spine lengths) where required for unequivocal identification. The characters used in the key allow the identification of genera and species groups by investigators with limited taxonomic experience; species separation in most cases requires some advanced dissection skills. Potential identification problems caused by difficulties discerning minute morphological features or intraspecific morphometric variability are discussed. The present version of the identification key still requires complementary illustrations of character states and inclusion of fact sheets summarizing the characteristics of each species with notes on taxonomic uncertainties and links to databases providing zoogeographical and genetic information.

Two new species of ectinosomatid copepods (Harpacticoida: Ectinosomatidae) from the Caribbean coast of Colombia

Biological samples from the lagoonal system Laguna Navío Quebrado, Caribbean Colombian coast, yielded 2 undescribed species of harpacticoid copepods of the family Ectinosomatidae. The first species, Halectinosoma arangureni sp. nov., is most closely related to H. langi Wells, 1967, H. curticorne (Boeck, 1873) and H. abyssicola (Bodin, 1968), but diverges from these congeners in: 1) the length-width ratio of the maxillipedal basis; 2) the outer caudal seta(II)/caudal ramus length ratio; 3) details of the mandible palp and blade; 4) the length of the inner exopodal seta of P5; 5) the accessory seta on the male P5 exopod, and 6) a T-shaped incision on the male third urosomite. The second species, Pseudobradya gascae sp. nov. closely resembles P. robusta Sars, 1910 and P. barroisi (Richard, 1893), but diverges from these species by: 1) the number of antennular segments in the female; 2) the absence of a seta on the antennary EXP2; 3) proportions of the maxilliped; 4) the relative length of P1EXP; 5) caudal seta III/caudal ramus length ratio, and 6) the unusually long middle seta of P5EXP. Both genera are recorded for the first time in Colombia.

First record of harpacticoid copepods from Lake Tahoe, United States: two new species of Attheyella (Harpacticoida, Canthocamptidae).

Benthic harpacticoids were collected for the first time at Lake Tahoe, California-Nevada, United States. Two species were identified as members of the genus Attheyella Brady, 1880. The genus Attheyella comprises about 150 species within six subgenera, but only twelve species have previously been reported from North American freshwater habitats. The two new species of Attheyella described here have a 3-segmented endopod on P1 and 2-segmented P2–P4 endopods, the distal segment of exopod of P2–P4 has three outer spines, and the P5 has five setae on the exopod and six setae on the baseoendopod. Attheyella (Attheyella) tahoensis sp. n. most closely resembles Attheyella (Attheyella) idahoensis (Marsh, 1903) from Idaho, Montana, and Alaska (United States) and Attheyella (Attheyella) namkungi Kim, Soh & Lee, 2005 from Gosu Cave in South Korea. They differ mainly by the number of setae on the distal endopodal segment of P2–P4. In addition, intraspecific variation has been observed on the caudal rami. Attheyella (Neomrazekiella) tessiae sp. n. is characterized by the extension of P5 baseoendopod, 2-segmented endopod of female P2–P3, and naked third seta of male P5 exopod. The two new species are likely endemic to Lake Tahoe, an isolated alpine lake within the Great Basin watershed in the western United States.

A new genus (Copepoda, Harpacticoida, Laophontidae) from Jeju Island of Korea.

A survey on the harpacticoid copepods from an intertidal zone in Hyeopjae sandy beach, Jeju Island, Korea, resulted in the discovery of an unusual laophontid, Jejulaophonte hyeopjaeensis sp. n., which cannot be placed in any extant genus within the family. To accommodate the species, a new genus of the family Laophontidae T. Scott, 1905 is proposed and fully described here. The new species is closely related to the lineage of the five primitive genera, Carraroenia McCormack, 2006, Coullia Hamond, 1973, Hemilaophonte Jakubisiak 1933, Psammoplatypus Lee & Huys, 1999, and Robustunguis Fiers, 1992 (the CCHPR-lineage) by the reduced P2 endopod, ovate shape of the female P5 exopod and sexual dimorphism in the P3 endopod. However, it displays discrepancies from the species of the CCHPR-lineage in the presence of an inner seta on P3 and P4 exp-2, four setae on P4 enp-2, and an inner seta on P3 and P4 enp-2 in the female. Furthermore, no other species within the family Laophontidae has three setae on P2 exp-3 and a seta on P2 enp-2 at the same time. The new species has sexual dimorphism in the antennule, genital segmentation and the legs from P2 to P5. The terminal seta on the second endopodal segment of P2 in the male is longer than that in the female. The endopod of P3 is 3-segmented and displays a short inner apophysis on the second segment in the male. The outer setae on the exopod of P3 and P4 are distinctly thicker and stronger in the male than in the female. Mitochondrial cytochrome oxidase subunit I (mtCOI) sequencing of the new species has been realized in order to be used in future phylogenetic analysis.

A new species of Harpacticella Sars, 1908 (Copepoda, Harpacticoida), from a tidal pool on Jeju Island, Korea.

A new species of the genus Harpacticella Sars, 1908 is described from a tidal pool on Jeju Island, Korea. Harpacticella jejuensis sp. n. is closely related to Harpacticella itoi Chang & Kim, 1991, with regard to the structure of P1 exp-1 and enp-1, the length of P1 exp-1 and exp-2, and the setal number of the P5 exopod in males. However, the new species is clearly distinguishable from Harpacticella itoi by the combined following characters: six setae on the P5 exopod in females, one naked seta on the inner margin of P1 exp-2, the short endopod of P1 compared to the exopod, and a naked long seta on the proximal inner margin of the P5 exopod of males. The mtCOI partial sequence is provided as a DNA barcode for the new species.

A new species ofEnhydrosoma(Copepoda: Harpacticoida: Cletodidae) from Korea, with redescription ofE. intermediaand establishment of a new genus

Abstract Two species of Enhydrosoma Boeck, 1873, found in muddy sediments in the sublittoral zone of Gwangyang Bay, represent the first record of this genus in Korea. Enhydrosoma coreana, new species, shares a number of rare morphological features with the type species, E. curticauda Boeck, 1872, such as a bifid rostrum with centrally inserted sensilla, endopodal lobe of P5 with a peduncle, and a characteristic shape of the female genital field. They differ in the armature formula of the mandible, P1 endopod, and P5 exopod, size of the P5 peduncle, and minor details in the ornamentation of several somites. Enhydrosoma intermedia Chislenko, 1978 is redescribed from its holotype, freshly collected Korean material, and freshly collected material from and near its type locality in the Russian Far East. Its male is described for the first time. Minor morphological differences are observed between these two disjunct populations, such as longer caudal rami and sparse hair-like spinules on somites in Korean speci...

A new species ofNitokraBoeck, 1865 (Copepoda: Harpacticoida: Ameiridae) from a brown alga in Thailand

Both sexes of a new species of Nitokra Boeck, 1865 were collected from a brown alga, Padina australis at Bangsaen sandy Beach in Chon Buri province, Thailand. Nitokra karanovici, sp. nov., is similar to many species of the genus in having a slender and cylindrical body shape, eight-segmented antennules in female and nine-segmented in male, exopod of female P5 with 5 setae; the new species shares the same armature formula of the swimming legs with the following six congeners: N. balli Rouch, 1972 from Long Island, Papua New Guinea; N. evergladensis Bruno, Reid & Perry, 2002 from Florida, U.S.A.; N. minor Willey, 1930 from Bermuda; N. minor mozambicae Wells, 1967 from Inhaca Island, Mozambique; N. platypus bakeri Chappuis, 1930 from the Philippines and Japan; and N. uenoi Miura, 1962 from Ryukyu Islands, Pacific. However, the new species can easily be distinguished from N. balli and N. uenoi by the number of setae on the female P5 Enp, and from N. evergladensis, N. minor and N. platypus bakeri by the much longer P1 Enp-1. Nitokra karanovici is most closely related to N. minor mozambicae, but it can be distinguished by the number of spinules on the anal operculum (6–7 in N. minor mozambicae and 11 in N. karanovici), and relative length of the P1 Enp-1 (slightly shorter in the new species). Therefore, we conclude that N. karanovici most resembles N. minor mozambicae as mentioned above.

A new species of the genusTigriopus(Copepoda: Harpacticoida: Harpacticidae) from Antarctica

Tigriopus kingsejongensis, new species, is described from tidal pools near the King Sejong Station on King George Island, Antarctica. The new species is closely related to Tigriopus kerguelenensis from Kerguelen Island. Both species share several characters, including the presence of an abexopodal seta on the allobasis of the antenna in the male, the setal formula of the swimming legs, and the shape of the P5 exopod in the female. However, the new species is distinguishable from its congeners by the combined characters of a relatively well-developed abexopodal seta on the antennary allobasis, and a knob-like structure in the middle of the lateral margin of the second endopodal segment of the P2 in the male. The new species belongs to the ‘Austral islands group' within the genus. The mtCOI gene sequence is provided as a DNA barcode for the new species, and a phylogenetic tree based on the DNA sequences is also suggested.

A new species of Paracrenhydrosoma (Copepoda: Harpacticoida: Cletodidae) from a subtidal muddy bottom of southern Korea, with a key to the species of Acrenhydrosoma-complex

A new species of Paracrenhydrosoma (Copepoda: Harpacticoida: Cletodidae) is described from samples taken from muddy bottoms in Jangmok, Geoje Island, Korea. The genus Paracrenhydrosoma is distinguished from other genera of the Acrenhydrosoma-complex (Acrenhydrosoma, Dyacrenhydrosoma and Neoacrenhydrosoma) by carrying an antennal exopod with two setae, P1 endopod with three setae, P3 endopod with two setae and P5 exopod with two setae. The new species differs from its congeners as follows: bifid rostrum on anterior margin, long caudal ramus, exceedingly long baseoendopodal mucroniform process of female P5 that reaches the end of the second free abdominal segment, and modified P3 endopod of male. A tabular key to aid in the identification of the Acrenhydrosoma-complex is provided. The worldwide distribution of the Acrenhydrosoma-complex is summarized and discussed.

A new genus of Cletopsyllidae (Copepoda, Harpacticoida) from Gulf of Mexico

A new genus and new species of the family Cletopsyllidae Huys & Willems, 1989 from deep-sea sediment in the Gulf of Mexico, are reported and fully described and illustrated. The new genus Pentacletopsyllus (type species: P. montagni sp. n.) can be distinguished from the four known genera of the family by antennule segmentation, length ratio of first and second endopodal segments of P1, and armature pattern on P5 exopod. It also differs from its sister genera by the rostrum being bifid at the tip, third segment of the female antennule having a smooth posterior margin, the baseoendopod of P5 with biarticulate outer setophore bearing basal seta, and female caudal rami without lobate expansion. A revised key to species of the family Cletopsyllidae Huys & Willems, 1989 is provided.

A new species of the genus Cerviniopsis from Sagami Bay, Japan and reinstatement of the genus Neocervinia, with a report on the male of Neocervinia itoi Lee & Yoo, 1998 (Copepoda: Harpacticoida: Aegisthidae)

A new aegisthid copepod, Cerviniopsis reducta sp. nov. is described from the deep sea in Sagami Bay, Japan. The new species has superficial resemblance to C. minutiseta Ito, 1983 in the armature formula of swimming legs. However they differ from each other in the shape of setae of the swimming legs, the distal margin of operculum, length of caudal rami, and the location of setae on P5 exopod. Also, the male of Neocervinia itoi Lee & Yoo, 1998 is described on the basis of samples collected from around the type locality in Sagami Bay, Japan. Sexual dimorphism of N. itoi male can be observed in the fused rostrum, atrophied mouthparts, P5, and P6. The sixth leg is symmetrical and both gonopores are presumably active, based on the presence of two spermatophores internally in the genital segment. This paper reports for the first time on the sexually dimorphic characters in the genus Neocervinia Huys, Mobjerg & Kristensen, 1997, reinstating its generic status with the newly revealed male characters.

A new species of the genus Cerviniopsis from Sagami Bay, Japan and reinstatement of the genus Neocervinia, with a report on the male of Neocervinia itoi Lee & Yoo, 1998 (Copepoda: Harpacticoida: Aegisthidae)

A new aegisthid copepod, Cerviniopsis reducta sp. nov. is described from the deep sea in Sagami Bay, Japan. The newspecies has superficial resemblance to C. minutiseta Ito, 1983 in the armature formula of swimming legs. However theydiffer from each other in the shape of setae of the swimming legs, the distal margin of operculum, length of caudal rami,and the location of setae on P5 exopod. Also, the male of Neocervinia itoi Lee & Yoo, 1998 is described on the basis ofsamples collected from around the type locality in Sagami Bay, Japan. Sexual dimorphism of N. itoi male can be observedin the fused rostrum, atrophied mouthparts, P5, and P6. The sixth leg is symmetrical and both gonopores are presumablyactive, based on the presence of two spermatophores internally in the genital segment. This paper reports for the first timeon the sexually dimorphic characters in the genus Neocervinia Huys, Mobjerg & Kristensen, 1997, reinstating its generic status with the newly revealed male characters.

Two new species belonging to the dentipes- and conifera-subgroups of Triconia (Copepoda: Cyclopoida: Oncaeidae) from the East China Sea

Two new species of Triconia in Oncaeidae, including both sexes of Triconia constricta n. sp. and females of Triconia pararedacta n. sp., are described from south of Jeju Island in the East China Sea. Triconia constricta belongs to the dentipes-subgroup of Triconia characterized by the absence of integumental pockets on the anterior surface of the labrum. It is distinguished from the closely related species of this subgroup, T dentipes (Giesbrecht, 1891), T elongata Bottger-Schnack, 1999, and T giesbrechti Bottger-Schnack, 1999, by the following combination of morphological features in females: 1) lateral margins of genital double-somite in dorsal view slightly constricted at midlength; 2) P5 with very long outer basal seta, reaching beyond paired secretory pores on posterior part of genital doublesomite, as well as distinctive length ratios of exopodal setae; in both sexes; 3) length ratios of caudal setae, and 4) relative spine lengths on distal endopodal segments of swimming legs 2 to 4. Triconia pararedacta is a member of the conifera-subgroup characterized by a dorsal projection on the second pedigerous somite in the female. It differs from females of other species of this subgroup in the following: 1) very small-sized dorsal projection on second pedigerous somite, 2) different length to width ratio of P5 exopod, 3) relative lengths of outer basal seta and exopodal setae of P5, and 4) different length ratio of outer distal spine to distal spine on endopods of P2-P4. Additional character states are proposed for defining the dentipes-subgroup within Triconia and for recognizing three sets of species within the conifera-subgroup.

Two new species of Paramphiascella Lang (Copepoda: Harpacticoida: Miraciidae) from a brackish water pond in Thailand

Two new species of the harpacticoid genus Paramphiascella Lang, 1944 were collected from a brackish water pond located at the Coastal Fisheries Research Development Center, Department of Fisheries, Samut Sakhon province, Thailand, and are described herein. Paramphiascella dahmsi sp. nov. and P. ferrarii sp. nov. are similar to other species of the genus in having a cylindrical body shape, eight-segmented antennules, and both the baseoendopod and exopod of the female P5 with five setae. However, the two new species can be distinguished from other congeners by having one big ovate-striated knob at the inner edge of the male P1 basis. Paramphiascella dahmsi bears in addition two ovatestriated knobs on the anterior surface of the proximal rim of the male P1 Enp1 while P. ferrarii is without any knobs on the endopod. The Enp2 of male P2 of P. dahmsi is distally attenuated, with a medially pointed knob close to Enp1. Adjacent to the knob there are two setae, one spinulose and one pectinate, and one club-like seta bifurcate at its tip. In P. ferrarii, the medial knob is rounded, a second long attenuation arises near the base of two unequal spinulose setae and the club-like seta is absent. In addition, the P2 Enp1 bears an inner spinulose seta in P. dahmsi, while in P. ferrarii it bears a pectinate seta. These characters are suggested as autapomorphies of the new species.

A new species of the genus Bryocamptus (Copepoda: Harpacticoida: Canthocamptidae) from Korea

Bryocamptus (Echinocamptus) cheongokensis sp. nov. is a harpacticoid copepod of the family Canthocamptidae that was collected from a pool in Cheongok cave, Donghae-shi, Kangwon-do, Korea. The new species is characterized by the following diagnostic characters: 1) an eight-segmented female antennule, 2) the absence of an inner seta on the second exopodal segment of P1, 3) the distal segments of the exopod of P2 to P4 are as long as the other two segments combined, and 4) there are six setae on the basoendopod of the female P5. This species has a slight resemblance to the “hiemalis” group. However, the new species is clearly distinguishable from the species in the “hiemalis” group by the combination of ornamentation of the free margin of the operculum, the number of setae on the P4 endopod, the length/width ratio of the P5 exopod in the female, and the number of setae on the first endopod segment and the lengths of each apical seta on the last endopod segment of P3 in the male. Thus far, 22 species have been reported in the subgenus Echinocamptus, and the “hiemalis” group includes ten species. Species in this group are typically found in the interstitial groundwater around springs, lakes, streams, and caves. The new species described herein is the first described member of the subgenus Echinocamptus from caves in Korea.