Dulzura projecta Ariyama, 2016, sp. nov.
Creators: name: Ariyama, Hiroyuki
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Hadziidae
Dulzura
Dulzura projecta

description: Dulzura projecta sp. nov.
(Figures 1 – 5)
Material examined
Holotype: male (OMNH-Ar-9974), 6.6 mm, Jogasaki coast, Wakayama City, Wakayama Prefecture, 34°17 ʹ 06 ″ N, 135°04 ʹ 08 ″ E, lower intertidal zone, reverse surface of large stone, 11 June 2006, coll. H. Ariyama. Paratypes: 2 males and 1 ovigerous female (OMNH-Ar-9975 – 9977), 5.2, 3.9, 4.4 mm, same data as holotype; 4 males and 1 ovigerous female (OMNH-Ar-9978 – 9982), 4.0, 3.5, 2.9, 2.9, 3.1 mm, Nagasaki coast, Misaki Town, Osaka Prefecture, 34°19 ʹ 49 ″ N, 135°09 ʹ 08 ″ E, 4 m depth, coarse sand, 9 October 2003, coll. H. Ariyama; 2 males and 1 ovigerous female (OMNH-Ar-9983 – 9985), 3.7, 2.7, 3.6 mm, southeastern coast of Kamishima Island, Toba City, Mie Prefecture, 34°32 ʹ 36 ″ N, 136° 59 ʹ 00 ″ E, 2.5 m depth, coarse sand, 26 July 2014, coll. H. Ariyama.
Description
Male [based on holotype, 6.6 mm (OMNH-Ar-9974), paratype, 5.2 mm (OMNH-Ar- 9975) for pleopod 3, and paratype, 4.0 mm (OMNH-Ar-9978) for antenna 1 and lower lip]. Body (Figure 1) slender; head small, antennal sinus present; pereonite 7 wider than anterior pereonites; pleonites wide; urosomites narrow, without dorsal robust setae.
Antenna 1 (Figure 2 (a)) long, with ratio of lengths of peduncular articles 1 – 3 1: 0.9: 0.3, peduncular article 1 with strong robust seta posterodistally, laterodistal surface setose; accessory flagellum short, with 4 setae; primary flagellum with 19 articles (probably regenerated), tip of flagellum with short article and long setae (Figure 2 (a1)). Antenna 2 (Figure 2 (b)) relatively short, with ratio of lengths of peduncular articles 3 – 5 1: 2.8: 2.6; flagellum with 15 articles.
Upper lip (Figure 2 (c)), ventral margin rounded, setose. Mandible (Figure 2 (d,d1,d2,e, e1)), incisor bearing 5 and 4 cusps in left and right, respectively, left lacinia mobilis long, 4-dentated, right lacinia mobilis with wide denticulate and narrow triangular lobes, number of accessory blades 8 on left side and 6 (2 thick and 4 thin) on right side; molar developed; palp article length ratio 1: 3.2: 3.3 in right, article 2 with 1 short and 1 long seta, article 3 bearing many setae on ventral margin and 1 thick and 2 thin long setae on tip, distal two-thirds of lateral surface covered with many tiny setae. Lower lip (Figure 2 (f)), medial margins of outer lobes setose, mandibular processes small. Maxilla 1 (Figure 2 (g,g1 – g3)), inner plate with 12 plumose setae medially; distal margin of outer
plate with 11 robust setae; palp article 2 narrow (left) or wide (right), distal end with 7 thin (left) or thick (right) robust setae. Maxilla 2 (Figure 2 (h)), both plates about same length, terminal ends bearing many setae. Maxilliped (Figure 2 (i,i1,i2)), inner plate truncate, distal margin with 4 robust setae; outer plate small, distal margin with 4 long thick setae, medial margin with 8 robust setae; palp stout, ventral surface of article 3 covered with short setae, article 4 with nail.
Gnathopod 1 (Figure 3 (a,a1)), coxa rhomboid, anterior and ventral margins with several short setae; basis stout, middle of posterior margin swollen, with 3 setae; ischium bearing 3 setae on posterodistal margin; merus short, posterodistal margin with 1 long and many short setae; carpus very long, straight, posterolateral surface with numerous long setae, medial surface sparsely setose; propodus short, about 0.4 times as long as carpus, anterodistal corner setose, posterodistal corner with 3 short robust setae, otherwise poorly setose; dactylus very short, tip slightly curved. Gnathopod 2 (Figure 3 (b,b1)) large; coxa roundish trapezoidal, produced posterodorsally, anterior and ventral margins with several short setae, gill large, subquadrate; basis relatively slender, middle of posterior margin slightly swollen, with 4 setae; merus short, posterodistal margin bearing 2 setae; carpus pyriform, posterior margin heavily setose; propodus very long, about 2.3 times as long as carpus, posterior margin slightly excavated at a point two-thirds, posterior and medial margins bearing numerous long setae, palm with 2 marginal and 4 + 2 medial small robust setae; dactylus robust, strongly curved, posterior margin lined with tiny curved setae.
Pereopods 3 – 4 (Figure 3 (c,d)) subequal; coxae roundish trapezoidal, ventral margins with several short setae, gills very large; bases straight, anterior margins with robust seta distally, posterior margins with 1 – 2 long setae and 3 – 4 short robust setae; meri anterior margins bearing 2 short robust setae; carpi with robust seta posterodistally; propodi bearing 4 pairs of short robust setae on posterior margins; dactyli short, almost straight. Pereopod 5 (Figure 3 (e)) longer than pereopods 3 – 4; coxa lobate, anterior half longer than posterior half, ventral margin with several short setae, posterior margin with seta, gill large; basis expanded, a little lobate posterodistally, with slightly serrate margin, anterior margin with 3 small robust setae, anterodistal corner setose; merus bearing long and short setae on anterodistal corner, posterior margin with 3 robust setae, posterodistal corner with 4 robust setae; carpus bearing 3 groups of setae on anterior margin, posterior margin with pair of short robust setae, posterodistal corner with several robust setae; propodus with seta and 3 groups of setae on anterior margin, posterior margin with 4 groups of robust setae; dactylus short, almost straight. Pereopod 6 (Figure 3 (f)) about 1.3 times as long as pereopod 5; coxa with small anteroventral lobe, posterior margin with seta, gill relatively small; basis expanded, posterodistal corner lobate, with slightly serrate margin, anterior margin with 7 small robust setae, anterodistal corner setose; merus bearing robust seta on middle anterior margin, anterodistal corner setose, posterior margin with 1 + 1 + 2 robust setae, posterodistal corner with 4 robust setae; carpus bearing seta and 3 groups of setae on anterior margin, posterior margin with 1 + 3 short robust setae, posterodistal corner with many robust setae; propodus, anterior and posterior margins with 5 and 4 groups of setae, respectively; dactylus short, almost straight. Pereopod 7 (Figure 3 (g)) slightly longer than pereopod 6; coxa flattenedtriangular, posterior margin with 3 setae; basis expanded, posterodistal corner lobate, with serrate margin, anterior margin with 6 small robust setae, anterodistal corner setose; merus without robust seta on anterior margin, anterodistal corner setose, posterior margin with 1 + 2 + 2 robust setae, posterodistal corner with 4 robust setae; carpus bearing 3 groups of setae on anterior margin, posterior margin with 1 + 3 short robust setae, posterodistal corner with many robust setae; propodus, anterior and posterior margins each with 5 groups of setae; dactylus short, almost straight.
Pleonal epimera (Figure 4 (a)), epimeron 1 slightly produced on posteroventral corner, ventral margin bare; epimeron 2 produced posteroventrally, ventral margin with 2 robust setae; epimeron 3 rounded on posteroventral corner, but posterodorsal corner sharply projected, ventral margin bearing many robust setae. Pleopods 1 – 2 (Figure 4 (b, c)) subequal, slender; peduncles long, each with 2 coupling hooks and posterodistal projection; outer rami shorter than inner, outer and inner rami with 12 and 11 articles in pleopod 1 and both with 10 articles in pleopod 2, respectively. Pleopod 3 (Figure 4 (d,e)), peduncle bearing lateral robust seta and anterodistal projection, medial surface with 2 coupling hooks and short seta; outer and inner rami each with 9 articles, outer ramus broad, article 1 with vertical ridge posteriorly, article 1 of inner ramus curved, with large outward projection distally. Uropod 1 (Figure 4 (f)) stout; peduncle with 1 basofacial, 4 dorsolateral and 3 dorsomedial robust setae, laterodistal end bearing extremely large robust seta; both rami almost same length, about 0.7 times as long as peduncle, outer ramus with 4 marginal and 5 terminal setae, inner ramus with 5 marginal and 5 terminal setae. Uropod 2 (Figure 4 (g,g1)) short, about 0.6 times length of uropod 1; peduncle bearing 4 dorsolateral and 1 dorsodistal robust setae, mediodistal corner with robust seta and comb of short setae; outer ramus about 0.9 times as long as peduncle, inner ramus longer than outer, about 1.1 times as long as peduncle, both rami with 5 marginal and 5 terminal robust setae. Uropod 3 (Figure 4 (h)) very large, about 1.6 times length of uropod 1; peduncle short, dorsal surface, lateral margin, dorsodistal margin and ventrodistal margin with 3, 2, 3 and 10 robust setae, respectively; outer ramus long, about 3.2 times as long as peduncle, article 1 broad, lateral and medial margins each with 4 groups of robust setae, distal margin with many robust setae, article 2 narrow, dirkshaped, 15% length of article 1, tip with 3 minute setae; inner ramus short, 28% as long as outer ramus, bearing 1 lateral and 2 medial robust setae, tip acutely projected. Telson (Figure 4 (i)) wider than long, deeply cleft, tips of both halves produced triangularly, both sides of projections each with 2 robust setae, lateral robust setae lacking.
Female [paratype, 3.1 mm (OMNH-Ar-9982)]. Gnathopod 1 (Figure 5 (a,a1)), coxa produced posterodorsally, anterior margin with several short setae, ventral margin with 2 long and 2 short setae; basis swollen on middle posterior margin, with 5 long setae; ischium bearing 3 setae on posterodistal margin; merus short, posterodistal margin with 1 long and several short setae; carpus not long, straight, posterior margin and mediodistal surface setose; propodus short, about 0.8 times as long as carpus, anterodistal corner setose, posterodistal corner with 2 short robust setae; dactylus very short, tip slightly curved. Gnathopod 2 (Figure 5 (b,b1)) smaller than that of male; coxa produced posterodorsally, anterior margin with 2 short setae, ventral margin with 2 long and 2 short setae, gill very large, ovoid, oostegite narrow, with 4 setae; basis slightly swollen on middle posterior margin, with 4 setae; merus short, posterodistal margin bearing 3 setae; carpus longish pyriform, posterior margin with many bundles of setae; propodus slightly long, about 1.1 times as long as carpus, posterior margin with 4 bundles of setae, anterodistal corner setose, palm bearing 2 robust setae medially; dactylus slender, weakly curved. Pleonal epimera (Figure 5 (c)), epimera 1 – 2 slightly produced posteroventrally, ventral margin bare in epimeron 1 and with robust seta in epimeron 2; epimeron 3 acutely projected on posteroventral corner, ventral margin bearing 2 robust setae. Pleopod 3 (Figure 5 (d)), lateral margin of peduncle with robust seta, mediodistal corner with 2 coupling hooks and short seta; outer and inner rami each with 7 articles, both rami slender, article 1 of inner ramus without projection. Other parts generally similar to male except for oostegites.
Small males. Paratype, 4.0 mm (OMNH-Ar-9978): gnathopod 1 (Figure 5 (e)), propodus about half length of carpus; gnathopod 2 (Figure 5 (f)), excavation and robust setae on palm almost same as holotype. Paratype, 2.9 mm (OMNH-Ar-9981): gnathopod 1 (Figure 5 (g)), propodus about 0.7 times as long as carpus; gnathopod 2 (Figure 5 (h)), excavation on palm absent, number of robust setae same as holotype, but proximal 2 setae larger.
Coloration in life
Whole body faintly yellowish white.
Etymology
From the Latin projecta (= projected), referring to the shape of male pleopod 3.
Remarks
In Dulzura projecta sp. nov. the inner ramus of male pleopod 3 has a projection on article 1 which differentiates it from other species in the genus. Such sexual dimorphism in pleopod 3 is also known for D. lobata, where the male pleopod 3 has a swelling on articles 1 in both rami (Stock and Vonk 1991). The very long carpus of male gnathopod 1 is also unique to D. projecta with other species of Dulzura having a shorter carpus. In D. projecta the bases of pereopods 5 to 7 are lobate, which is also seen in D. lobata, and the male epimeron 3 has a sharp projection on the posterodorsal corner which is shared with D. hamakua and D. paucispinosa.
Distribution
From Osaka Prefecture to Mie Prefecture in Japan.
Habitat
Under large stones and in coarse sand, probably interstitial; from the lower intertidal zone to 4 m depth.
description: Published as part of Ariyama, Hiroyuki, 2016, Two new species of eyeless amphipods from a coastal area in Japan (Crustacea: Amphipoda: Hadziidae, Melitidae), with reinstatement of the genus Paraniphargus Tattersall, 1925, pp. 2277-2297 in Journal of Natural History 50 on pages 2279-2287, DOI: 10.1080/00222933.2016.1198838, http://zenodo.org/record/3993161