Protodulichia scandens Ariyama and Hoshinoı, 2019

Ariyama, Hiroyuki & Hoshino, Osamu, 2019, A new superfamilyı familyı genus and species of marine amphipodı Protodulichia scandensı from Japan (Crustacea: Amphipoda: Senticaudata: Corophiida), Journal of Natural History 53 (39), pp. 2467-2477 : 2470-2476

publication ID	https://doi.org/ 10.1080/00222933.2019.1704588
DOI	https://doi.org/10.5281/zenodo.3671788
persistent identifier	https://treatment.plazi.org/id/CC343640-E86E-FFCF-F338-298E55D1FD6F
treatment provided by	Valdenar
scientific name	Protodulichia scandens Ariyama and Hoshinoı
status	sp. nov.

Treatment

Protodulichia scandens Ariyama and Hoshinoı sp. nov.

( Figures 1 – 5 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 )

[Japanese name: Bōnobori-yokoebiı new]

Type locality

Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı Japanı 34°47 ʹ 15 ” Nı 139°24 ʹ 31 ” Eı 25 m depth.

Material examined

Holotype. Male (OMNH-Ar-11171)ı 2.8 mmı Akinohama Beachı Izu Oshima Island (Oshima Town)ı Tokyo Prefectureı 25 m depthı coarse sand bottomı 13 June 2017ı coll. O. Hoshino. Paratypes: 2 males and 1 ovigerous female (OMNH-Ar-11172 – 11174)ı 3.0ı 2.4ı 3.1 mmı same data as holotype; ovigerous female (OMNH-Ar-11175)ı 2.7 mmı same locality as holotypeı 11 June 2017ı coll. O. Hoshino .

Description

Male [based on holotypeı 2.8 mm (OMNH-Ar-11171)ı and paratypeı 3.0 mm (OMNH Ar-11172) for mandible]. Body ( Figure 1 View Figure 1 ) smooth; headı dorsal margin roundedı lateral cephalic lobe trianguları posteroventral margin with small projectionı eyes about 0.4 times as long as head; pereonite 7ı posterodistal margin rotated posteriorly; pleonal epimera roundedı smooth; urosomite 1 not longı about 115% length of pleonite 3.

Antenna 1 ( Figure 2 View Figure 2 (aıa1)) with ratio of lengths of peduncular articles 1 – 3 1:1.2:0.95ı peduncular article 1 without ventral robust setae; accessory flagellum 2-articulate; primary flagellum with 6 articlesı posterior margin bearing aesthetascs. Antenna 2 ( Figure 2 View Figure 2 (b)) about 1.3 times length of antenna 1; peduncleı ratio of lengths of articles 3 – 5 1:2.35:3.55ı posterior margin sparsely setose; flagellum slenderı with 4 articlesı terminal article minute.

Upper lip ( Figure 2 View Figure 2 (c)) broadı fleshyı ventral margin with minute setae. Mandible ( Figure 2 View Figure 2 (dıd1ıd2ıeıe1ıe2))ı incisor with 4 and 5 cuspsı lacinia mobilis with 3 and 4 cusps in left and rightı respectivelyı 3 wide accessory blades present in both sides; molar developedı with spatula-like process; palpı length ratio of articles 1 – 3 1:2.5 – 2.6:2.0 – 2.1ı articles 2ı 3 setose. Lower lip ( Figure 2 View Figure 2 (f)) with well-developed inner lobesı outer lobes each with mandibular lobeı distal margins covered with thin setae. Maxilla 1 ( Figure 2 View Figure 2 (gıg1))ı inner plate long trianguları without setae; outer plate bearing 9 terminal robust setae distally; palp 2-articulateı article 2 bearing 5 robust setae apically and several setae dorsally. Maxilla 2 ( Figure 2 View Figure 2 (h))ı both plate with distal setaeı inner plate lacking mediofacial row of setae. Maxilliped ( Figure 2 View Figure 2 (iıi1))ı inner plate with 3 short ventrodistal robust setae; outer plate bearing 8 marginal robust setae mediodistally; palp consisting of 4 articlesı article 2 longı article 4 with slender nail.

Gnathopod 1 ( Figure 3 View Figure 3 (a))ı coxa longer than wideı posteroventral corner with small notch; basis slightly curved anteriorly; posterodistal margin of merus and posterior margin of carpus setose; propodus setose mediallyı posterior margin with several thick setae; dactylus longı slender. Gnathopod 2 ( Figure 3 View Figure 3 (bıb1))ı coxa subtrapezoidalı posteroventral corner with small notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus trianguları posterodistal corner setose; propodus largeı about 1.85 times length of carpusı palm smoothı bearing 6 robust setae; dactylus narrow.

Pereopods 3ı 4 ( Figure 2 View Figure 2 (cıc1ıd)) subsimilar to each other; coxae subquadrateı posteroventral corner of coxa 4 slightly produced; bases widened in middleı many granules present in each gland; meri – dactyli slender. Pereopod 5 ( Figure 2 View Figure 2 (eıe1)) shorter than pereopod 4; coxa wideı bilobedı both lobes each with robust seta; basis subovateı length about 1.65 times widthı anterior margin with lateral ridgeı posterodistal corner expanded; carpus and merus each bearing several robust setae. Pereopod 6 ( Figure 3 View Figure 3 (fıf1)) about 1.25 times length of pereopod 5; coxa narrowı bilobedı anterior lobe with robust seta; basis ovalı length about 1.4 times widthı anterior margin with lateral ridgeı posterodistal corner widely expanded; carpus and merus each with several robust setae. Pereopod 7 ( Figure 4 View Figure 4 (a)) about 1.55 times length of pereopod 6; coxa roundish triangular; basis narrowed distallyı length about 1.75 times widthı anterior margin with lateral ridgeı posteroproximal corner projectedı posterodistal corner not expanded; carpus – propodus slenderı elongateı each with several robust setae.

Pleopods 1 – 3 ( Figure 4 View Figure 4 (bıcıd))ı peduncles each with 2 coupling hooksı pleopods 2ı 3 bearing 2 and 4 setaeı respectively; outer rami slightly longer than inner ramiı outer rami with 9ı 10ı 10 articles and inner rami with 8ı 8ı 9 articlesı respectively.

Uropod 1 ( Figure 4 View Figure 4 (e))ı peduncle with 3 dorsomedial robust setaeı mediodistal corner slightly projected; outer ramus about 0.9 times as long as peduncleı about 0.8 times length of inner ramusı outer ramus with 4 dorsalı 2 subterminal and 1 terminal robust setaeı inner ramus bearing 5 dorsomedialı 2 subterminal and 1 terminal robust setae. Uropod 2 ( Figure 4 View Figure 4 (f)) about 0.75 times length of uropod 1; peduncle mediodistal corner slightly projectedı with robust seta; outer ramus about 1.3 times as long as peduncleı about 0.65 times length of inner ramusı outer ramus with 3 dorsal and 1 terminal robust setaeı inner ramus bearing 4 dorsomedial and 2 terminal robust setae. Uropod 3 ( Figure 4 View Figure 4 (g)) about half length of uropod 2; peduncle laterodistal corner slightly projectedı medial margin with seta; outer ramus about 2.05 times as long as peduncleı about 0.9 times length of inner ramusı outer and inner rami with 0 – 1 dorsal and 2 dorsomedial robust setaeı respectivelyı both rami each bearing minute terminal robust seta. Telson ( Figure 4 View Figure 4 (h)) smoothı without setaeı length about 1.3 times widthı dorsodistal end slightly produced.

Ovigerous female [based on paratypeı 3.1 mm (OMNH-Ar-11174)]. Gnathopod 2 ( Figure 4 View Figure 4 (iıi1))ı coxa largeı anterior margin swollen in middleı posteroventral corner without notch; basis with anterolateral ridge; merus posterodistal margin setose; carpus longish trianguları posterior margin setose; propodus slenderı about 1.2 times length of carpusı palm smoothı bearing 4 robust setae; dactylus longı slender.

Variation. Uropod 3ı outer and inner rami with 0 – 1 and 1 – 2 dorsal robust setaeı respectively ( Table 1 View Table 1 )ı minute terminal robust seta present on each ramus in all specimens.

Colouration in life

Male ( Figure 5 View Figure 5 (a)): whole body light red and whiteı eyes silver. Female ( Figure 5 View Figure 5 (b)): head pale orangeı anterior pereonites dark redı other parts of body almost whiteı eyes silver.

Distribution

Known only from the type locality.

Ecology

This new species builds a mast and clings to the mast on a coarse sand bottom at a depth of 25 m ( Figure 5 View Figure 5 ). The mast is about 6 – 7 mm in length and light grey in colourı and several sand grains are attached on. Such behaviour was observed only in the family Dulichiidae (e.g. Mattson and Cedhagen 1989; Neretin et al. 2017)ı and this is the first record in the other amphipods.

Etymology

From the Latin scandens (= scandentı climbing)ı referring to the ecology.