Parvipalpus holocaudatus, Jung & Yoon, 2015

Jung, Tae Won & Yoon, Seong Myeong, 2015, New records of Nuuanuidae (Crustacea: Amphipoda: Senticaudata) from Korean waters, with descriptions of one new genus and two new species, Journal of Natural History 50, pp. 1045-1072 : 1048-1057

publication ID	https://doi.org/ 10.1080/00222933.2015.1103914
publication LSID	lsid:zoobank.org:pub:E604D161-C386-4883-A15F-1628F2B29B7A
DOI	https://doi.org/10.5281/zenodo.4328877
persistent identifier	https://treatment.plazi.org/id/03D287DF-D04F-FFC9-FE61-FAF9FBDDFBF9
treatment provided by	Carolina
scientific name	Parvipalpus holocaudatus
status	sp. nov.

Treatment

Parvipalpus holocaudatus View in CoL sp. nov.

(Korean Name: Ga-neun-chae-jjik-yeop-sae-u, new)

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

Type material

Holotype. Adult male, 4.0 mm, dissected on slide glasses, NIBRIV0000305388, Beom Island, Seogwipo-si, Jeju-do, Korea (33°13′39″N, 126°34′03″E), 20 November 2008, SCUBA diving (depth 30 m), collected by T. W. Jung. GoogleMaps

Allotype. Adult female, 5.5 mm, dissected on slide glasses, NIBRIV0000305389, collection details same as holotype.

Description

Holotype, male. Head ( Figure 1A View Figure 1 ), rostrum minute; anterior cephalic lobe obtuse subrectangular, antennal sinus not developed and forming small notch anteriorly; eyes hardly developed with separated ommatidia and boundary indistinct.

Antenna 1 ( Figure 1B, C View Figure 1 ) longer than antenna 2; peduncular article 1 somewhat convex and robust; peduncular article 2 elongate, subequal to peduncular article 1, and slightly concave mesially; peduncular article 3 as long as 0.42 times peduncular article 2, with accessory flagellum distally; accessory flagellum 4-articulate, distal one considerably reduced, distal margins of each article with several setae; flagellum longer than peduncular articles 1 – 3 combined and 22-articulate, each article with several setae distally; calceoli, aesthetasc absent.

Antenna 2 ( Figure 1D View Figure 1 ) about half of antenna 1; gland cone acute; peduncular article 3 short, margins convex; peduncular article 4 slightly dilated, distal margin with several setae posteriorly; peduncular article 5 slender and shorter than peduncular article 4; flagellum 12-articulate and subequal to peduncular articles 4 and 5 combined, each article with short setae distally; calceoli, aesthetasc absent.

Upper lip ( Figure 1E View Figure 1 ) obtuse triangular, apical margin convex with fine setae distally.

Lower lip ( Figure 1F View Figure 1 ) with well-developed mandibular processes bearing round apices; outer lobe round apically with several stout and curved setae; inner lobe weak.

Left mandible ( Figure 1G, H View Figure 1 ), incisor and lacinia mobilis 5-dentate, respectively; accessory setal row with 11 dentate setae; molar processes well developed with one long, several short plumose setae and short bristles; palp just bi-articulate, each article degenerated and last article with minute apical seta.

Right mandible ( Figure 1I View Figure 1 ), incisor 5-dentate; lacinia mobilis multi-dentate bifid; accessory setal row with seven dentate setae.

Maxilla 1 ( Figure 1J, K View Figure 1 ), inner plate, apex produced, inner margin lined with long feebly plumose setae; outer plate, apex lined with 10 dentate robust spines; palp bi-articulate, article 1 short and distal corner obliquely truncated, article 2 with five stout spines apically and two thin setae subapically.

Maxilla 2 ( Figure 1L View Figure 1 ), inner plate, surface with oblique row of 11 plumose setae, distal half of inner margin with five plumose setae, apical margin with apical and subapical rows of setae; outer plate also with rows apically and subapically.

Maxilliped ( Figure 1M – O View Figure 1 ), inner plate rectangular with three spines on apical margin and with several plumose setae on apical and subapical margins; outer plate, lateral margin round and slightly expanded, distal one-third of inner margin and apex lined with nine spatulate and two acute spines that successively increasing in length, outer surface with several setae along inner margin; palp 4-articulate, article 1 short and obliquely truncated distally, article 2 weakly swollen mesially, inner margin of article 3 hump-like mesially bearing several setae and subdistal margin lined with row of numerous spinules, article 4 falcate with row of spinules on inner margin and stout spine apically.

Gnathopod 1 ( Figure 2A – C View Figure 2 ), coxa somewhat extended anteroventrally, ventral margin subround and lined with minute setae; posteroventral corner weakly dilated backward with notch bearing short seta; basis linear, anterior margin straightened with four short mesial setae, posterior margin with two long mesial and pair of distal short setae and distal two-thirds shallowly convex; ischium lobate anteriorly with group of setae near posterodistal corner; merus, posterior margin convex and distal half with two rows of several pectinate setae, distal corner weakly produced; carpus elongate, slightly shorter than basis, anterior margin weakly convex with two mesial setae, posterior margin crenulate lined with several groups of pectinate setae, proximal margin oblique, lateral and medial surfaces with several oblique rows of setae; propodus weakly extended distally, anterior margin slightly longer than half of carpus with two groups of medial setae and distal corner with group of three setae, distal half of posterior margin with two groups of setae, lateral and medial surfaces near distal corner with group of three bifid robust spines, respectively; palm distinct, slightly convex and lined with several setae; dactylus falcate and fitting palm, inner margin with three setae.

Gnathopod 2 ( Figure 2E, F View Figure 2 ) larger than gnathopod 1; coxa subrectangular, anterior and ventral margins convex lined with minute setae, posteroventral corner with small notch bearing short seta; basis linear and weakly curved proximally, distal half of anterior margin with four minute setae, posterior margin with two long mesial and pair of short distal setae; ischium slightly lobate anteriorly, posterodistal corner with short seta; merus subrectangular, posterodistal corner little produced with three minute setae; carpus drastically extended distally, anterior margin convex with distal spine, posterior margin lobate baring group of three setae; propodus enlarged and bud-like shape, anterior margin bare and distal corner with group of four setae, medial surface with row of paired setae anterodistally, posterior margin lined with numerous long setae, palm indistinct, palmer margin with five spines; dactylus falcate and stout, not reaching half of posterior margin.

Pereopod 3 ( Figure 3A View Figure 3 ), coxa similar but more convex anterior margin than that of coxa on gnathopod 2; basis slender and curved, anterior margin lined with seven minute setae, posterior margin with two long and seven minute setae; ischium with small anterior lobe, posterodistal corner with short seta; merus trapezoidal, anterior margin weakly expanded anterodistally and proximal one-third weakly angulate bearing short seta, posterodistal corner produced with pair of short setae and small spine, posterior margin straightened and posterodistal corner with pair of setae; carpus shorter than merus, anterior margin bare and distal corner with short seta and small spine, posterior margin lined with three paired spines; propodus slender and subequal to carpus in length, anterior margin slightly convex mesially and anterodistal corner with setae, posterior margin lined with four pairs of spines; dactylus elongate and slightly curved, inner margin with short seta, apex forming unguis.

Pereopod 4 ( Figure 3B, C View Figure 3 ) similar in size and shape to pereopod 3 except for slightly larger coxa bearing weakly produced posteroventral margin, without notch on posteroventral corner and slightly extended anteroventral corner.

Pereopod 5 ( Figure 3D View Figure 3 ), coxa subquadrate, ventral margin equilobate, anterior lobe round and posterior lobe slightly angulate ventrally; basis, anterior margin swollen and lined with several stout spines, posterior margin weakly serrate and lined with minute setae and posterodistal corner angulate; ischium subquadrate, anterodistal corner with spine, posterior lobe small; merus, anterior margin bare and distal corner with hook-shaped projection bearing pair of seta and spine, posterior margin expanded, dilated mesiodistally and lined with two minute setae, posterodistal corner produced with stout spine; carpus quadrate and longer than merus, little wider distally, anterior margin lined with three mesial and group of three distal spines, posterior margin bare and distal corner with pair of stout spines; propodus as long as carpus, weakly convex proximally, anterior margin lined with 1-1-2-2 spines in formula from proximal to distal and with pair of small locking spines, posterior margin bare and distal corner with group of two stout and one normal spines; dactylus, inner margin with seta, outer margin with penicillate seta, unguis short and curved.

Pereopod 6 ( Figure 3E View Figure 3 ) slightly longer than pereopod 5; coxa bilobate, anterior lobe small, posterior lobe dilated posteroventrally; basis larger than that of pereopod 5, anterior margin lined with nine spines and proximal half swollen, posterior margin largely expanded, serrated and lined with minute setae; ischium subquadrate, anterodistal corner with spine, posterior lobe small; merus expanded distally, anterior margin with minute spine and distal corner with hook-shaped projection bearing large spine; posterior margin drastically expanded with mesial small spine and distal corner produced distally with large spine, distal margin concave; carpus quadrate, anterior margin with 2-2-1 spines in formula from proximal to distal and distal corner with pair of stout spines, posterior margin with two minute mesial setae and distal corner with pair of stout spines; propodus stout and shorter than carpus, anterior margin with 1-2-2-3 spines in formula from proximal to distal and distal corner with pair of locking spines, posterior margin bare and distal end blunt with two stout spines; dactylus, inner margin with seta, unguis short and curved.

Pereopod 7 ( Figure 3F View Figure 3 ), coxa unilobate with notch on ventral margin, posteroventral margin round and lined with minute setae; basis, anterior margin swollen proximally and lined with several spines, anterodistal corner with pair of spines, posterior margin largely expanded backward and about distal two-fifths slightly angulate, margin weakly serrated and lined with minute setae; ischium quadrate, anterior margin with pair of distal spines, posterior lobe small; merus expanded posterodistally, anterior margin with mesial spine and distal corner with hook-shaped projection bearing pair of spines; posterior margin with mesial spine and distal corner produced with stout spine; carpus quadrate and little wider distally, anterior margin with 2-1-1 spines in formula from proximal to distal and distal corner with four spines, posterior margin bare and distal corner with stout spine; propodus as long as carpus, anterior margin with 2-3-3 spines in formula from proximal to distal and distal corner with pair of spines, posterodistal end blunt with two stout spines and seta; dactylus, inner margin with seta, unguis short and curved.

Pleon ( Figure 4A View Figure 4 ), dorsal keel very weak; pleonal epimeron 1, ventral margin with elongate produced lobe curved anteriorly; pleonal epimera 2 and 3 ordinary and each posteroventral margin subacute.

Pleopod 1 ( Figure 4B View Figure 4 ), peduncle subquadrate and slightly diminished in width distally, with four retinaculae; each ramus subequal to peduncle and all articles of rami with plumose long setae distally; inner and outer rami 6-articulate and 8-articulate, respectively.

Pleopod 2 ( Figure 4C View Figure 4 ) similar to pleopod 1, but inner ramus 5-articulate.

Pleopod 3 ( Figure 4D View Figure 4 ), peduncle subquadrate, slightly wider in width distally, with four retinaculae and three plumose setae at mediodistal corner; inner ramus subequal to peduncle, 5-articulate; outer ramus slightly longer than peduncle, 8-articulate; all articles of rami with plumose long setae distally.

Uropod 1 ( Figure 4E View Figure 4 ); peduncle with basofacial spine, dorsolateral and dorsomedial margins with three spines, respectively, each distal corner with enlarged spines and mediodistal spine larger than laterodistal; each ramus stout and gradually diminished in width; inner ramus, dorsomedial margin lined with three spines, apex with three small and one normal subapical, and one enlarged apical spines; outer ramus with one small dorsomedial and two dorsolateral spines, apex with two small and one normal subapical, and one enlarged apical spine.

Uropod 2 ( Figure 4F View Figure 4 ) shorter than uropod 1; peduncle also shorter than that of uropod 1, distal corner of dorsolateral margin with stout spine, dorsal surface with small distal spine; each ramus stout and gradually diminished in width; inner ramus, dorsomedial margin lined with four small spines, apex with two pairs of large and small one subapical and one enlarged apical spines; outer ramus lined with two spines dorsally, apex with pair of subapical and one enlarged apical spines.

Uropod 3 ( Figure 4G, H View Figure 4 ) biramus; peduncle short, medial margin convex, dorsal surface with small spine; mediodistal and laterodistal corner with spine, respectively; inner ramus reduced and triangular in shape, margin finely wrinkled, apex with spine; outer ramus larger than inner and subequal to peduncle in length, uni-articulate, width diminished distally, medial margin finely wrinkled, apex with several spines.

Telson ( Figure 4I View Figure 4 ) never cleft and almost hexagonal, distal and lateral surfaces with setae, distal margin wrinkled.

Allotype, female. Gnathopod 1 ( Figure 5A – C View Figure 5 ) similar to that of male except for numbers and positions of setae.

Gnathopod 2 ( Figure 5D, E View Figure 5 ) not enlarged but slightly larger than gnathopod 1; propodus longer than carpus, gradually diminished in width; palm distinct and oblique; dactylus short.

Coxal gills ( Figure 5F – J View Figure 5 ) suboval, that of pereopod 3 largest and that of pereopod 6 smallest.

All oostegites slender ( Figure 5F – J View Figure 5 ).

Urosome ( Figure 4J View Figure 4 ) diminished but not coalesced; dorsal keel very weak; urosomite 2 with two dorsal spines; urosomite 3 with two round lobes on dorsal margin.

Etymology

The composite epithet of the specific name, holocaudatus , is a combination of the Greek holos and the Latin cauda, meaning ‘ entire tail ’. This name refers to the shape of the telson, which is not cleft.

Remarks

This new species, P. holocaudatus shows similar shapes of propodus and dactylus on gnathopod 2 in mature males to Gammarella berringar ( Barnard, 1974) and Nuuanu merringannee ( Barnard, 1974) , but it is distinguished readily from G. berringar by the following characters: dorsal keel of urosomite 1 is absent; uropod 3 is more reduced; and telson is entire in P. holocaudatus . The new species can also be discriminated from N. merringannee by bi-articulate mandibular palp, produced anteroventral corner on pleonal epimeron 1, uni-articulate outer ramus of the uropod 3, and entire telson.