Paragrandidierella urauchiensis, Ariyama, 2013

Ariyama, Hiroyuki, 2013, Reinstatement of Paragrandidierella (Crustacea: Amphipoda: Aoridae) from Japan, with the Description of a New Species, Species Diversity 18, pp. 223-235 : 224-229

publication ID	https://doi.org/ 10.12782/sd.18.2.223
publication LSID	lsid:zoobank.org:pub:8C5EF755-9772-41E1-BDF5-4E13C36ACE87
persistent identifier	https://treatment.plazi.org/id/63447647-19E5-4880-802B-C290FA757D81
taxon LSID	lsid:zoobank.org:act:63447647-19E5-4880-802B-C290FA757D81
treatment provided by	Felipe
scientific name	Paragrandidierella urauchiensis
status	sp. nov.

Treatment

Paragrandidierella urauchiensis View in CoL sp. nov. ( Figs 1–4 View Fig View Fig View Fig View Fig )

[New Japanese name: Urauchi-himedorosokoebi]

Paragrandidierella sp. : Association of Interdisciplinary Study at the Drainage and Estuarine Area of Urauchi River, Iriomote Island, Southern Japan 2006: 18, fig. 7c-1.

Material examined. Holotype: male (OMNH-Ar- 9543), 3.1 mm, mouth of Urauchi River in Iriomote Island , Okinawa Prefecture (24°24.9′N, 123°46.7′E), tidal flat near stand of mangroves Rhizophora stylosa Griffith , 3 September 2005, coll. N. Okuda et al GoogleMaps . Paratypes: one male (OMNH- Ar-9544), 3.2 mm, same data as holotype; two males (OMNH-Ar-9545, 9546), 3.0, 2.6 mm, one ovigerous female (OMNH-Ar-9547), 2.5 mm, and one female (OMNH- Ar-9548), 2.4 mm, same place, 7 March 2005, coll GoogleMaps . N GoogleMaps . Okuda et al.

Description of male [based mostly on holotype, supplemented by one paratype (OMNH-Ar-9545) for lower lip, telson, and uropod 3]. Body ( Fig. 1 View Fig ) slender. Eyes medium-sized (18% as long as head). Posteroventral corners of pereonites 5–7 strongly produced. Urosomites without dorsal keel or ridge.

Antenna 1 ( Fig. 2A, A View Fig 1 View Fig ) long, about 0.7 times as long as body; length ratio of peduncular articles 1–3 1.0: 1.0: 0.3; flagellum with 16 normal and 1 minute articles, articles 7–16 each with aesthetasc on ventrodistal corner. Antenna 2 ( Fig. 2B View Fig ) relatively short, length (peduncular articles 3–5 and flagellum) about half as long as body; length ratio of peduncular articles 3–5 1.0: 1.3: 1.0, ventrodistal corner of article 5 not inflated; flagellum short, but longer than peduncular article 5, consisting of 7 normal and 1 minute articles, flagellar articles 3–7 each with 2 robust setae.

Upper lip ( Fig. 2C View Fig ) with ventral margin almost straight, bearing many thin setae. Left mandible ( Fig. 2D, D View Fig 1 View Fig ) with length ratio of palp articles 1–3 1.0: 2.5: 1.7, articles 2 and 3 with 2 and 8 setae, respectively; incisor with 3 cusps, lacinia mobilis with 2 cusps. Right mandible ( Fig. 2E, E View Fig 1 View Fig ) with length ratio of palp articles 1–3 1.0: 2.5: 2.0, articles 2 and 3 with 2 and 7 setae, respectively; incisor with 4 cusps, lacinia mobilis with 3 cusps. Lower lip ( Fig. 2F View Fig ) covered with thin setae on apical parts of outer and inner lobes. Maxilla 1 ( Fig. 2G, G View Fig 1 View Fig , G 2 View Fig ) with outer plate bearing 3 robust and 7 normal setae. Maxilla 2 ( Fig. 2H View Fig ) with inner plate setose on distal margin, inner margin with sparse fine setae. Maxilliped ( Fig. 2I, I View Fig 1 View Fig ) with inner plate produced mediodistally, distal and medial margins bearing many plumose setae; outer plate broad, middle and proximal parts strongly inflated laterally, medial margin with 2 plumose setae and 6 thick, robust setae.

Gnathopod 1 ( Fig. 3A, A View Fig 1 View Fig ) greatly enlarged; carpus extremely wide, posterodistal corner with long, acute tooth (ca. 55% as long as carpus proper); propodus narrow, middle part of posterior margin expanded; dactylus elongatetriangular, distal part of posterior margin with 2 minute notches. Gnathopod 2 ( Fig. 3B, B View Fig 1 View Fig ) slender; posterodistal margin of merus setose; carpus elongate, posterior margin with many thick and normal setae; propodus relatively long; dactylus with 3 denticles posterolaterally.

Pereopods 3 and 4 ( Fig. 3C, C View Fig 1 View Fig , D) with coxae roundishrectangular, bases slender, meri dilated distally, carpi longer than meri, propodi narrow, and dactyli long and dirkshaped. Pereopod 5 ( Fig. 3E View Fig ) with coxa short, posterior half narrower than anterior; basis rectangular, anterodistal corner with several setae; merus relatively broad; carpus with 3 lateral and 1 posterodistal robust setae; propodus with 3 lateral and 2 posterodistal robust setae; dactylus short, with plumose seta. Pereopod 6 ( Fig. 3F View Fig ) about 1.4 times as long as pereopod 5; coxa with posterior half narrower than anterior; basis relatively broad, anterior margin with 2 short robust setae, distal half of posterior margin with many plumose setae and 3 robust setae; merus with 3 anterior and 1 lateral robust setae; carpus with 4 lateral robust setae, anterodistal and posterodistal corners bearing thick setae; propodus with 4 lateral robust setae, posterior margin and anterodistal corner with long setae; dactylus bearing plumose seta. Pereopod 7 ( Fig. 3G View Fig ) about 1.5 times as long as pereopod 6; coxa small, anterior part produced ventrally; basis ovoidal, anterior margin with short robust seta, anterodistal part of lateral surface bearing several plumose setae, posterior margin with many plumose setae and 3 robust setae; merus with 1 lateral and 4 medial robust setae; carpus with 6 lateral and 1 medial robust setae; propodus bearing 4 robust setae on anterior margin and 2 medial thick setae, anterodistal corner with long, thick seta; dactylus with plumose seta.

Epimeral plates 1–3 ( Fig. 4A View Fig ) each with 1–4 long, plumose setae on ventral margin and short seta on posteroventral corner. Pleopods ( Fig. 4B–D View Fig ) with outer rami of 7–8 articles, inner rami of 6 articles. Uropod 1 ( Fig. 4E View Fig ) stout; dorsal surface of peduncle with 2 robust setae distally; outer ramus slightly longer than inner, former with 2 dorsal and 4 terminal robust setae, latter bearing 1 dorsal and 4 terminal robust setae. Uropod 2 ( Fig. 4F View Fig ) with peduncle shorter than wide; rami a little longer than peduncle, outer ramus shorter than inner. Uropod 3 ( Fig. 4G View Fig ) with peduncle a little shorter than single ramus, latter with 4–5 long setae terminally. Telson ( Fig. 4G View Fig ) with several setae on margins and swellings.

Description of female [based on paratype (OMNH- Ar-9548)]. Generally similar to male holotype except for antennae, gnathopods, and oostegites. Antenna 1 ( Fig. 4H View Fig ) relatively short, about 0.45 times as long as body; length ratio of peduncular articles 1–3 1.0: 0.9: 0.4; flagellum with 9 normal and 1 minute articles, articles 6, 8, and 9 each with aesthetasc on ventrodistal corner. Antenna 2 ( Fig. 4I View Fig ) short, 0.3 times as long as body; length ratio of peduncular articles 3–5 1.0: 1.3: 1.4; flagellum very short, same length as peduncular article 5, consisting of 3 normal and 1 minute articles, flagellar articles 2 and 3 each with 2 robust setae. Gnathopod 1 ( Fig. 4J, J View Fig 1 View Fig ) with coxa trapezoidal; basis broadened distally; merus triangular, posterior margin with a few setae; carpus relatively broad, posterior margin with several thick and normal setae; propodus slender, distal half of posterior margin with 3 robust setae; dactylus with denticle on distal part of posterior margin. Gnathopod 2 ( Fig. 4K, K View Fig 1 View Fig ) subequal in size to gnathopod 1, similar to that of male, but carpus and propodus shorter.

Variation in male gnathopod 1 (4 males examined). Small male [paratype, 2.6 mm (OMNH-Ar-9546), Fig. 4L View Fig ]: almost same as that of holotype. Large male [paratype, 3.2 mm (OMNH-Ar-9544), Fig. 4M View Fig ]: tooth of carpus greatly longer than that of holotype (ca. 95% as long as carpus proper); propodus long and slender, without expansion.

Etymology. From the type locality.

Remarks. This new species differs from P. minima in the absence of an inflated ventrodistal corner of peduncular article 5 in the male antenna 2.

Distribution. Known only from the type locality.

Habitat. Sandy tidal flat, middle to lower intertidal zone (Association of Interdisciplinary Study at the Drainage and Estuarine Area of Urauchi River, Iriomote Island, Southern Japan 2006).