Dulichiopsis barnardi Laubitz, 1977

Ariyama, Hiroyuki, 2019, Four Species of Dulichiidae (Crustacea: Amphipoda) from Japan, with the Description of a New Genus and Two New Species, Species Diversity 24 (1), pp. 29-48 : 40-44

publication ID	https://doi.org/ 10.12782/specdiv.24.29
publication LSID	lsid:zoobank.org:pub:7287B998-E838-400C-94C7-B66C21FF35FE
DOI	https://doi.org/10.5281/zenodo.4734568
persistent identifier	https://treatment.plazi.org/id/1B069A22-FFC3-4427-3AD1-FB8AFE12FDBC
treatment provided by	Felipe
scientific name	Dulichiopsis barnardi Laubitz, 1977
status

Treatment

( Figs 11–13 View Fig View Fig View Fig )

[Japanese name: Shakutoridoronomi-modoki, new]

Dulichia remis: Barnard 1964: 332 , fig. 12m–u. (non Dulichia remis Barnard, 1964 )

Dulichiopsis barnardi Laubitz, 1977: 955 , fig. 7.

Material examined. Male (OMNH-Ar-10823), 8.5 mm, off Namie Town , Fukushima Prefecture, 37°28′38"N, 141°58′38"E (KS14-6, No. 4; Fig. 1B View Fig ), 531–540 m depth, using beam trawl, 2 May 2014, coll GoogleMaps . T. Takano.

Diagnosis. Eyes composed of many dispersed ommatidia. Maxilla 1 outer plate bearing 9 terminal robust setae. Maxilla 2 inner plate with mediofacial row of setae subdistally. Male gnathopod 2, basis widened distally, propodus massive, ovoid, posterior margin weakly setose, with large proximal projection and small distal projection. Pereopod 4 basis slender. Pereopod 5 elongate, prehensile. Urosomite 1 about 1.6 times as long as pleonites 2+3. Uropod 2 outer ramus about half length of inner ramus.

Description of male [based on male (OMNH-Ar-10823), 8.5 mm]. Body ( Fig. 11 View Fig ), dorsal margins of pereonites and pleonites slightly corrugated, urosomite 1 about 1.6 times as long as pleonites 2+3. Eyes round, large, about one third length of head, composed of many dispersed ommatidia.

Antenna 1 ( Fig. 12A View Fig ), peduncular article 1 with single ventral robust seta; peduncular articles 2, 3, accessory flagellum and primary flagellum lost. Antenna 2 ( Fig. 12B View Fig ), peduncular article 3 short; peduncular articles 4, 5 and flagellum lost. Upper lip ( Fig. 12C View Fig ), ventral margin with sparse short setae. Mandibles ( Fig. 12D, D View Fig 1, E, E1 View Fig ) with length ratio of palp articles 1–3 1.0: 2.6: 1.6, articles 2 and 3 with 12 and 9–10 setae, respectively; incisor with 6 cusps, lacinia mobilis with 4 and 5 cusps in left and right, respectively, 3 and 4 accessory blades present in left and right, respectively; molar with spatula-like process in right. Lower lip ( Fig. 12 F View Fig ), outer and inner lobes covered with thin setae apically. Maxilla 1 ( Fig. 12G, G View Fig 1 View Fig , G 2 View Fig ), inner plate round, palp article 2 bearing 7 robust setae apically. Maxilla 2 ( Fig. 12H View Fig ), inner plate with distal setae and many subdistal mediofacial setae, outer plate bearing many setae on distal margin. Maxilliped ( Fig. 12I View Fig ), inner plate with 3 apical and 1 mediodistal short robust setae on ventral surface; outer plate bearing 10 slender robust setae mediodistally.

Gnathopod 1 ( Fig. 13A View Fig ) slender; coxa subrectangular; merus setose posterodistally and mediodistally; carpus long, with many setae on posterior margin and several setae on medioproximal surface; propodus densely setose posteriorly and mediodistally; dactylus long, slender, curved posteriorly, posterior margin lined with minute setae. Gnathopod 2 ( Fig. 13B, B View Fig 1 View Fig ), coxa subtrapezoidal, gill slender; basis widened distally, curved anteriorly, anterodistal corner slightly lobate, lateral surface with several sensory setae; carpus subtriangular, weakly setose; propodus massive, ovoid, about 1.5 times as long as head, about 1.55 times length of carpus, posterior margin weakly setose, with large proximally-oriented proximal projection at about 100° angle to palm and small distal projection at about 35° angle to palm; dactylus stout, posterior margin with small quadrate projection proximally.

Pereopod 3 ( Fig. 13C View Fig ), coxa triangular, gill long; other parts lost. Pereopod 4 ( Fig. 13D View Fig ) slender; coxa triangular, gill long; basis slender, about 4.45 times as long as width, with glands in anterior and posterior parts; merus long. Pereopod 5 ( Fig. 13E, E View Fig 1 View Fig ) about 2.0 times length of pereopod 4; coxa bearing short setae, gill short; basis and merus very long, carpus about 1.2 times as long as propodus; lateral surfaces of basis, merus and carpus with many small robust setae; propodus with palm, anterior margin lined with robust setae. Pereopods 6, 7 ( Fig. 13F View Fig ) lost except for coxae.

Pleopods ( Fig. 13 View Fig G–I), peduncles progressively longer, each with 2 slender coupling hooks; outer rami slightly longer than inner rami, outer rami with 16, 16, 15 articles and inner rami with 15, 15, 13 articles respectively. Uropod 1 ( Fig. 13J View Fig ), peduncle with 10 lateral and 5 medial robust setae; outer ramus about 0.7 times as long as inner ramus, outer ramus with 14 lateral and 4 medial robust setae, inner ramus bearing 13 lateral, 15 medial and 2 distal robust setae. Uropod 2 ( Fig. 13J View Fig ) about 0.7 times length of uropod 1; peduncle with 2 lateral and 4 medial robust setae; outer ramus about half length of inner ramus, outer ramus with 3 lateral and 2 medial robust setae, inner ramus bearing 4 lateral and 7 medial robust setae. Telson ( Fig. 13J View Fig ) with 4 setae dorsally.

Coloration in life. Unknown.

Remarks. Laubitz (1977) described this species based on the female specimens. The present male specimen, however, can be identified as Dulichiopsis barnardi , because (1) the eyes are composed of many dispersed ommatidia, (2) the maxilla 2 inner plate has mediofacial setae subdistally, (3) the urosomite 1 is much longer than the pleonites 2+3, and (4) the uropod 2 outer ramus is about half length of the inner ramus.

Habitat. Bottom sediment unknown, 531–540 m depth (present study); 882 m depth ( Laubitz 1977).

Distribution. Japan: off Namie Town, Fukushima Prefecture (present study). USA: off the Near Islands in the Aleutian Islands, Alaska ( Laubitz 1977).