Mandibular Palp Article Research Articles

Species of the Maera-clade collected from Japan. Part 4: addenda to genera Maera Leach, 1814 and Quadrimaera Krapp-Schickel Ruffo, 2000, with revised keys to Japanese species of the clade (Crustacea: Amphipoda: Maeridae).

Two new species of Maera Leach, 1814 and Quadrimaera Krapp-Schickel Ruffo, 2000 included in the Maera-clade are described from Japan. Maera denticoxa sp. nov. was collected from Iwate and Hokkaido Prefectures and can be distinguished from its congeners by the small notches on the posteroventral margins of coxae 1-6. Quadrimaera angulata sp. nov. from north of Tanegashima Island in Kagoshima Prefecture is characterized by the distal tooth on the mandibular palp article 1, the rounded palm of the female gnathopod 2, and the angular posterodistal margin of the pereopod 7 basis. Keys to Japanese species of the Maera-clade are provided. In total, seventeen species included in the clade occur in Japan.

Species of the Maera-clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum),with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae).

Two species of Maera Leach, 1814, a species of Meximaera Barnard, 1969 and a species of Orientomaera Ariyama, 2018 included in the Maera clade, are described from Japan. Maera loveni (Bruzelius, 1859) was collected from the Sea of Japan and can be distinguished from its congeners by the very large body size and the gnathopod 2 palm defined by a blunt tooth bearing a strong robust seta. Maera sagamiensis sp. nov. from Sagami Bay is characterized by the presence of small notches on the coxae 1-3. Meximaera mooreana (Myers, 1989) was collected from Wakayama Prefecture and has two distinct characters: the male gnathopod 2 with wide basis and the very long uropod 3. Morphological characters of the Japanese specimens resemble well those in the literature, but the mandibular palp article 1 is projected acutely. Orientomaera incisa sp. nov. was recently collected from Wakayama Prefecture and its gnathopods 2 in both sexes bear a distinctive incision on the palm. Keys to species of Meximaera in the world and Japanese species of the Maera-clade are provided. Fifteen species included in the Maera-clade occur in Japan.

Species of the Maera-clade collected from Japan. Part 1: genera Maeropsis Chevreux, 1919 and Orientomaera gen. nov. (Crustacea: Amphipoda: Maeridae).

The Maera-clade is a group of maerid amphipod genera which has neither a falcate mandibular palp nor medially setose inner plates of maxillae 1 and 2. Two species of Maeropsis Chevreux, 1919 and four species of Orientomaera gen. nov. included in the clade, are described from Japan. Maeropsis okinawensis sp. nov. is described, based on collections from Okinawa Prefecture. It resembles M. cobia Krapp-Schickel, 2009, M. paphavasitae Wongkamhaeng, Coleman Pholpunthin, 2013, and M. serratipalma (Nagata, 1965). This new species differs from the latter three species in the long uropod 3. Maeropsis serratipalma is redescribed and newly recorded from Kanagawa, Osaka and Wakayama Prefectures. The new genus, Orientomaera, is described and is characterized by the mandibular palp article 1 without a distal tooth and the oblique palm of the gnathopod 2 with many robust setae. Orientomaera comprises four species: O. brevispina (Kim Kim, 1991) comb. nov. from Iwate, Fukui, Kyoto and Wakayama Prefectures and Ariake Sea; O. decipiens sp. nov. from Osaka and Wakayama Prefectures; O. obliquua sp. nov. from Osaka and Wakayama Prefectures; O. rotundicoxa sp. nov. from Kanagawa and Wakayama Prefectures. These species can be distinguished from one another by the coxa 1, the gnathopod 2 propodus, the pereopod 6 basis and the telson. Keys to species of Maeropsis and Orientomaera in the world are provided.

A new species of Eusirus from Jeju Island, Korea (Crustacea, Amphipoda, Eusiridae)

A new eusirid amphipod, Eusirus bulbodigitus sp. n., from Jeju Island, Korea is described with a detailed description and illustrations. Eusirus bulbodigitus sp. n. shows common features with the five known eusirid amphipods Eusirus abyssi Stephensen, 1944, Eusirus columbianus Bousfield & Hendrycks, 1995, Eusirus hirayamae Bousfield & Hendrycks, 1995, Eusirus laticarpus Chevreux, 1906, and Eusirus parvus Pirlot, 1934, such as the mandibular palp article 3 bearing a group of setae laterally. However, this new species is differentiated by the combination of the following characteristics: the eyes are poorly developed, the propodus on pereopod 4 is slightly shorter, the inner margin of dactylus on pereopod 4 is swollen, the length of pereopods 5–7 is moderate, the urosomite 1 has a dorsal protrusion distally, and the telson is shallowly cleft. This is the first record of the genus Eusirus Krøyer, 1845 from Korean waters.

Two new species of pontogeneiid amphipods (Crustacea, Senticaudata, Calliopioidea) from Korean waters.

Two new pontogeneiid amphipods, Eusiroides pilopalpus sp. n. and Paramoera dentipleurae sp. n., from Korean waters are described and illustrated. Eusiroides pilopalpus sp. n. can be distinguished from congeners by the following characters: mandibular palp article 3 has brush-like setation, maxilla 2 has an inner plate that is not enlarged, and gnathopods 1 and 2 ischium has a well-developed anterior lobe. Paramoera dentipleurae sp. n. can be discriminated from congeners by the following characters: head anterior cephalic lobe is sinusoid, pereopods 5–7 are homopodous and slender, pereopods 6 and 7 basis are proximally lobed but distally diminished on posterior margins, and epimeron 3 is prominently expanded posterodistally.

Ampithoe qeshmensis sp. nov. (Amphipoda: Ampithoidae), a new herbivorous amphipod from the Persian Gulf

Herbivorous amphipods of the family Ampithoidae have an important role in marine ecosystems. Ampithoe qeshmensis sp. nov. is a new member of Ampithoidae from the Qeshm Island, Persian Gulf. The new species resembles A. kava, A. katae and A. cookana based on the second male gnathopod. Ampithoe qeshmensis sp. nov. is characterized by round and reduced distoventral spur on uropod 1 in male, mandibular palp article 3 longer than second one, robust seta on palm of second male gnathopod, and longer flagellum than peduncular article 5 on the second antenna.

A new species of the rare genus Priscomilitaris from the Seto Inland Sea, Japan (Crustacea, Amphipoda, Priscomilitaridae).

A new species of the priscomilitarid amphipod, Priscomilitaris heike, from the Seto Inland Sea, Japan, is named and described. This new species is the third species of Priscomilitaridae and the second species of Priscomilitaris. Additionally, nucleotide sequences of nuclear 28S rRNA and histone H3 as well as mitochondrial cytochrome c oxidase subunit I from its holotype were determined. Priscomilitaris heike sp. n. is distinguished from its congener, Priscomilitaris tenuis Hirayama, 1988, by having deep antennal sinus, long flagellar article 1 of antennae 1 and 2, long mandibular palp article 2, 10 robust setae on outer ramus of maxilla 1, and rounded epimeral plates. A key to the species of Proscomilitaridae is provided.

Maeridae from the Indo-Pacific: Elasmopus, Leeuwinella gen. nov., Maeropsis, Pseudelasmopus and Quadrimaera (Amphipoda: Crustacea).

Twenty-two species of Maeridae including the new genus, Leeuwinella, and eight new species are described from Indo-Pacific waters. Leeuwinella mistakensis gen. et sp. nov. from southern Western Australia has dorsal carinae and serrate epimeral margins on pleonites 1-3 and mandibular palp article 3 concave; this significant combination of characters justifies erection of a new genus. Elasmopus coxacallus sp. nov., with a castelloserrate posterior margin of pereopod 7 presents a novel character for the genus, which contains over 100 described species. Elasmopus incomptus sp. nov. and E. norfolkensis sp. nov. are also described from Norfolk Island, South Pacific, while new distribution records are provided for E. gracilis Schellenberg, 1938, E. integer Myers, 1989, and E. molokai J.L. Barnard, 1970 from northwestern Australia, and E. souillacensis Appadoo & Myers, 2003, from the Kermadec Islands. New distribution records for Maeropsis griffini (Berents, 1983) from Bedout Island in Western Australia are the first of the species outside the Queensland type locality and new records of M. thetis (Lowry & Springthorpe, 2005) from mainland Australia to Tasmania and across the Tasman Sea extending its range. Pseudelasmopus walkerae sp. nov. is described from Norfolk Island, and is the second species recorded in the genus, previously known only from Mauritius. Lastly, three new Quadrimaera species, Q. gregoryi, Q. brownorum and Q. vallaris, along with eight known Quadrimaera species, are reported from various locations extending their distributions in the Indo-Pacific.

Leucothoe kawesqari, a new amphipod from Bernardo O'Higgins National Park (Chile), with remarks on the genus in the Magellan Region (Crustacea, Peracarida).

Although the genus Leucothoe has been reported repeatedly in the Magellan Region, the citations in the Channels and Fjords Ecoregion were either unidentified or attributed to the previously considered cosmopolitan Leucothoe spinicarpa. In this work, Leucothoe kawesqari sp. n. is described, which can be distinguished from other species of the genus in the Southern Ocean by having eyes present, epimeral plates with no setae, anterior coxae not acutely produced or excavate, coxa 5 slightly bilobed, accessory flagellum present, mandibular palp article 3 shorter than ½ article 2, pereopods 5–7 basis expanded, ovoid, posterior margin weakly crenulate and telson apex irregularly truncated. The new species was found in hard substrates, both unvegetated and with macroalgae, mainly in kelp forest of Macrocystis pyrifera.

New species and records of Apseudomorpha (Crustacea: Tanaidacea) from Taiwan.

The present study reports the first record of Apseudomorpha from Taiwan and includes descriptions of three new species and one new species record. Paradoxapseudes pangcahi sp. nov. differs from the most similar congener, Paradoxapseudes littoralis, by having one segment less in the antennal flagellum and fewer segments in the uropod endopod. Pseudoapseudomorpha tagopilosus sp. nov. is distinguished from its most similar congener, Pseudoapseudomorpha ornata, by having one long lateral seta on pleonite 4, a four-segmented antennular outer flagellum, and a male with smaller and thinner 'small' cheliped than that of the female and with vestigial pleopods on pleonite 3. Indoapseudes multituberculata sp. nov. stands out from its congeners by having pleopods only on the last two pleonites in females, many small tubercles terminally on the pleotelson, and mandibular palp article 1 with noticeable distal teeth. The Synapseudes species recorded in the present study morphologically agrees with Synapseudes hansmuelleri that was originally described from the Tioman Archipelago, Malaysia, South China Sea. Morphological comparisons between each of the three newly described species and its congeners are tabulated.

Description of a new species of Sternomoera (Crustacea: Amphipoda: Pontogeneiidae) from Japan, with an analysis of the phylogenetic relationships among the Japanese species based on the 28S rRNA gene.

A new species of amphipod, Sternomoera morinoi Tomikawa and Ishimaru, is described from subterranean aquatic habitats in Shiga Prefecture, Japan. In addition, Relictomoera tsushimana (Uéno, 1971) from a well on the island of Tsushima in Japan is transferred to Sternomoera and redescribed based on the holotype. Sternomoera morinoi sp. nov. is most similar to S. tsushimana (Uéno, 1971) comb, nov., but is distinguished by having many fine setae on the body, a shorter antenna 1, fewer C-setae on mandibular palp article 3, a shorter mandibular palp article 3, sparsely setose anterior margins of coxae 1-4, a different armature of the palmar margins of gnathopods 1 and 2, and no long setae on the posterior margin of the basis in gnathopod 2 and pereopods 3 and 4. The phylogenetic relationships among the Japanese species of Sternomoera are also estimated, based on partial DNA sequences of the nuclear 28S rRNA gene.

Dulichiella celestun, a new species of amphipod (Crustacea: Amphipoda: Melitidae) from the Gulf of Mexico, with a key and zoogeographic remarks for the genus in the western Atlantic

The discovery of a new melitid amphipod in the Celestun Biosphere Reserve (northern Yucatan peninsula, SE Gulf of Mexico) is reported. Dulichiella celestun sp. nov. differs from its congeners by an unique set of characteristics: truncated lateral cephalic lobe, mandibular palp article 1 having inner margin produced distally, carpus longer than the propodus of gnathopod 1, gnathopod 2 propodus distolateral crown with four spines, pereopods 3-7 dactylar unguis anterior margin with two accessory spines, and urosomite 3 bearing four dorsal spines. A key to species and zoogeographical affinities among members of the genus in the western Atlantic are also provided.

Coboldus chazaroi, a new species of iphimediid amphipod (Amphipoda, Gammaridea, Iphimediidae) from a submarine cave, north Cuba

The amphipods of Coboldus are considered as antipolar members of iphimediids with loss of a maxilla 1 palp article 2. Anew amphipod species of the genus Coboldus (Family Iphimediidae) collected from soft bottom in a submarine cave,Northern Cuba, is described. Coboldus chazaroi sp. nov., differs from all other known species by the following characters:pereonal dorsal processes bifid and equal in length, coxa 1 ventrally acute and bifid, article 5 of gnathopod 2 longer than6, dactylus longer than palm, posterior margin of pleonal epimeron 3 with 3 teeth, mandibular palp article 2 with 1 subdistal plumose seta, molar poorly developed with 1 basal seta, lacinia mobilis rectangular and finely serrate.