Leucothoe pansa, Kristine N. White & Traudl Krapp-Schickel, 2017

Kristine N. White & Traudl Krapp-Schickel, 2017, Red Sea Leucothoidae (Crustacea: Amphipoda) including new and re-described species, European Journal of Taxonomy 324, pp. 1-40 : 19-23

Leucothoe pansa sp. nov.

urn:lsid:zoobank.org:act:EA53097A-C5E3-4B72-B3F8-E07C59D917B4

Figs 8–9

Diagnosis

Head anterior margin oblique, produced, distal margin excavate with rounded projection. Maxilla 1 palp 1-articulate. Gnathopod 1 coxa broader than long; carpus curved; propodus proximally inflated: dactylus reaching 0.3 times propodus length. Gnathopod 2 basis distally expanded, stout; carpus distally tapered, pointed; propodus palm concave with 2 small tubercles. Pereopods 5–7 bases narrowly expanded; meri and carpi posteriorly expanded.

Etymology

After the Latin ‘ pansus ’, meaning ‘stretch, spread, expand’ and referring to the distinctly expanded meri of pereopods 5–7, used as adjective.

Type material

Holotype

SUDAN: ♂, 3.4 mm, Port Sudan, Marsa Arakiyai, stn 195, 1–3 m, sponge, 12 Aug. 1970, U. Schiecke leg. (ZMB 29748, slide 5094).

Paratype

SUDAN: ♀, 3.2 mm, same data as holotype (ZMB 29749, slide 5095).

Additional material examined

SUDAN: 1 ♂, 3 mm, Port Sudan, Dec. 1970. U. Schiecke leg.

Description

Male

LENGTH. 3.4 mm.

HEAD. Anterior margin oblique, anterodistal margin subquadrate, distal margin straight; ventral cephalic keel anterior margin excavate; anteroventral margin quadrate, ventral margin produced; eyes present with many ommatidia, round. Antenna 1 0.2 times body length, flagellum 3-articulate, peduncle article 1 width less than 2 times article 2, accessory flagellum present, 1-articulate. Antenna 2 length 0.18 times body length, shorter in length than antenna 1, flagellum 3-articulate. Mandibular palp ratio of articles 1–3 1.0:2.2: 1.3, article 2 with 1 distal seta, article 3 with two distal setae, incisors weakly dentate; left mandible with 8 raker spines, lacinia mobilis large, strongly toothed; right mandible with 7 raker spines, lacinia mobilis very small, weakly toothed. Upper lip asymmetrically lobate, anterior margin weakly setose. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1-articulate, with 3 distal slender setae; outer plate with 4 distal robust setae and 7 distal slender setae. Maxilla 2 inner and outer plates each with 3 distal slender setae. Maxilliped inner plates distal margin rounded with v-shaped indentation, with short and long simple setae; outer plate inner margin smooth, reaching 0.2 times palp article 1, with simple marginal setae; palp article 4 subequal in length with article 3, distally acute.

PErEON. Coxae 1–4 relative widths 1.0: 1.0: 1.1: 1.3. Gnathopod 1 coxa smooth, bare, anterodistal margin produced, subquadrate, distal margin straight, posterior margin slightly excavate; basis proximally expanded, anterior and posterior margins bare; ischium bare; carpus curved, distal length 8.5 times width, proximal margin smooth; propodus proximally inflated, palm smooth with 2 distal setae; dactylus smooth, reaching 0.3 times propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, bare, anterior margin straight, anterodistally rounded, distal margin straight, posterior margin straight; basis distally expanded, stout, anterior margin with 1 seta, posterior margin bare; carpus 4.8 times propodus length, curved, distally tapered, pointed, anterior margin smooth; propodus with 1 mediofacial setal row at midline, reaching 0.5 times propodus length, posterior margin smooth, palm concave with 2 minor tubercles; dactylus curved, proximal margin smooth, bare, anterior margin distally acute, reaching 0.5 times propodus length. Pereopod 3 coxa length 0.7 times width, anterodistal corner overriding distal face of coxa 2, smooth, anterior margin rounded, distal margin slightly rounded, posterior margin slightly excavate. Pereopod 4 coxa anterior margin rounded, serrate, distal margin rounded, posterior margin straight. Pereopods 5–7 bases width-length ratios 1: 1.9, 1: 1.9, 1:1.4, posterior margins smooth, bare; meri and carpi posteriorly expanded.

PLEON. Epimera 1–3 bare, epimeron 3 posteroventral corner rounded. Uropods 1–3 relative lengths 1.0: 0.9: 1.0. Uropod 1 peduncle 0.7 times inner ramus length, outer ramus subequal in length with inner ramus. Uropod 2 peduncle and outer ramus 0.8 times inner ramus length. Uropod 3 peduncle 1.3 times inner ramus length, outer ramus 0.9 times inner ramus length. Uropod 1 inner ramus with robust setae, uropods 1–3 outer rami with robust seta(e). Uropods 1–3 inner and outer rami lined with fine setae. Telson 1.8 times longer than wide, apex weakly tridentate.

Female (sexually dimorphic characters) Similar in all aspects to male.

Remarks

Leucothoe pansa sp. nov. shares the characters mentioned for L. acanthopus such as the uni-articulate maxilla 1 palp and short gnathopod 1 dactylus with the sub-species level clade documented in White & Reimer (2012) as well as the inflated gnathopod 1 propodus. This species is also similar to L. acanthopus in having pereopods 5–7 bases narrowly expanded and a smooth gnathopod 2 propodus palm. The gnathopod 2 propodus differs from that of L. acanthopus in having a concave palm. The host for this species is an unidentified sponge species (Porifera).

Distribution

Red Sea (present study).

Depth range

1–3 m.

Figures

Fig. 8. Leucothoe pansa sp. nov, holotype, ♂, length 3.4 mm (ZMB 29748, slide 5094).

Fig. 9. Leucothoe pansa sp. nov., holotype, ♂, length 3.4 mm (ZMB 29748, slide 5094).