Kamaka songkhlaensis, Ariyama, Hiroyuki, Angsupanich, Saowapa & Rodcharoen, Eknarin, 2010

Ariyama, Hiroyuki, Angsupanich, Saowapa & Rodcharoen, Eknarin, 2010, Two new species of the genus Kamaka (Crustacea: Amphipoda: Kamakidae) from Songkhla Lagoon, southern Thailand, Zootaxa 2404, pp. 55-68 : 62-67

publication ID	https://doi.org/ 10.5281/zenodo.194167
DOI	https://doi.org/10.5281/zenodo.6206731
persistent identifier	https://treatment.plazi.org/id/03BE0B0C-FFB7-FFBF-B88A-CD1DFCEDFCD8
treatment provided by	Plazi
scientific name	Kamaka songkhlaensis
status	sp. nov.

Treatment

Kamaka songkhlaensis sp. nov.

( Figs 6–9 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 )

Kamaka cf. taditadi Angsupanich et al., 2005: 375 . — Ruensirikul et al., 2007: 1233, fig. 5.

Not Kamaka taditadi Thomas & Barnard, 1991: 311 , figs 1–4. — Krapp-Schickel & Myers, 2006: 1091, figs 5–7.

Material examined. Holotype: male, 2.5 mm (OMNH-Ar-7754), Outer Songkhla Lagoon ( Fig. 1 View FIGURE 1 B; 07°11'04''N, 100°25'03''E), 0.35 m deep, fine sand, 21 psu in salinity, 10 Oct. 2008, coll. S. Angsupanich. Allotype: female, 2.4 mm (OMNH-Ar-7755), same data as holotype. Other paratypes: 2 males, 2.2, 1.7 mm (OMNH-Ar-7756, 7757); 2 males and 1 female, 1.9, 1.8, 2.2 mm (PSUZC-CR0229 to 0231); 1 male and 1 female, 1.9, 2.2 mm (PSUZC-CR0232, 0233; not dissected), same data as the holotype.

Description. Male [based on holotype, 2.5 mm (OMNH-Ar-7754)]. Body ( Fig. 6 View FIGURE 6 ) slender, smooth. Eyes medium-sized. Antenna 1 ( Fig. 7 View FIGURE 7 A) with ratio of lengths of peduncular articles 1–3 1:1.2:0.9, peduncular article 1 with 2 penicillate setae at ventrodistal corner; flagellum with 9 medium-sized articles, articles 7–9 each with aesthetasc at ventrodistal corner. Antenna 2 ( Fig. 7 View FIGURE 7 B, B1) with distinct swelled article 4, ratio of lengths of peduncular articles 3–5 1:2.6:1.7; flagellum with 1 long, 4 medium-sized and 1 tiny distal article, article 1 excavate posteriorly, with serrate posterior margins, tip of article 5 with several setae.

Upper lip ( Fig. 7 View FIGURE 7 C) bearing short thin setae. Mandible ( Fig. 7 View FIGURE 7 D, D1, E, E1) with left and right incisors bearing 4 and 5 cusps, respectively; left lacinia mobilis with 4 cusps, right 2 cusps; tips of accessory blades blunt (acute in paratypes); palp with article 3 broadened distally, article length ratio 1:1.4:1.2, articles 1–3 with 1, 6 and ca. 13 setae, respectively. Lower lip ( Fig. 7 View FIGURE 7 F) with mandibular process short, central part of outer lobe with a roundish cavity-like structure, apical parts of inner and outer lobes covered with thin setae. Maxilla 1 ( Fig. 7 View FIGURE 7 G, G1) with outer plate bearing 10 robust setae apically; tip of palp article 2 with 4 robust, 4 thin and many feeble setae. Maxilla 2 ( Fig. 7 View FIGURE 7 H) with both plates wide, setose apically. Maxilliped ( Fig. 7 View FIGURE 7 I) with inner plate bearing several thick plumose setae distally; outer plate with 8 medial robust setae.

Gnathopod 1 ( Fig. 8 View FIGURE 8 A) with coxal plate large, posteroventral corner right-angled, bearing 15 fine setae and 1 robust seta on anterior/ventral and posterior margins, respectively; basis with long seta posteriorly; carpus with many thick setae and normal setae on posterior margin and medial surface, respectively; propodus setose anteriorly and posteriorly; dactylus with denticle on posterior margin. Gnathopod 2 ( Fig. 8 View FIGURE 8 B) with coxal plate roundish, bearing 3 ventral setae and 1 posterior robust seta; basis elongate, posterodistal corner with short seta; merus relatively short, posterodistal corner rounded; carpus roundish triangular; propodus broad, with acute process on posteroproximal corner, distal margin rounded, with many setae, posterior margin of process with several setae; dactylus elongate, strongly curved posteriorly, anterior and posterior margins each with a few setae.

Pereopods 3 and 4 ( Fig. 8 View FIGURE 8 C, C1, D) with coxal plates roundish square, each bearing 4 ventral setae and 1 posterior robust seta; basis of pereopod 3 with long seta; meri with several setae at anterodistal corners; dactyli short. Pereopod 5 ( Fig. 8 View FIGURE 8 E) with coxal plate wide, anterior lobe with a few setae ventrally, posterior lobe with short plumose seta at posteroventral corner; basis slightly expanded, anterior margin with 5 simple setae, anterodistal corner with 3 simple setae, posterior margin with 5 plumose and 1 simple setae; merus with thick seta at posterodistal corner; carpus with 1+3 robust setae; propodus with 2 robust and 1 plumose setae distally. Pereopod 6 ( Fig. 8 View FIGURE 8 F) about 1.6 times as long as pereopod 5; coxal plate narrow, anterior margin with long robust seta, posteroventral corner with short plumose seta; basis almost linear, anterior margin with 6 plumose and 2 simple setae, anterodistal corner with 1 plumose and 3 simple setae, posterior margin with 5 plumose and 2 simple setae; merus with anterodistal robust seta and posterodistal long seta; carpus with 1+1+4 robust setae; propodus with 1+2 robust setae, distal end with 3 long and 2 short simple setae and 1 plumose seta; dactylus curved. Pereopod 7 ( Fig. 8 View FIGURE 8 G) about 1.2 times as long as pereopod 6; coxal plate not lobate, posteroventral corner with short plumose seta; basis almost linear, anterior margin with 5 plumose and 1 simple setae, anterodistal corner with 3 simple setae, posterior margin with 6 plumose and 2 robust setae; merus with 1+1 long robust setae posteriorly; carpus with 1+1+2 robust setae; propodus with 1+2 anterior and 1 posterior robust setae, distal end with 4 long and 2 short simple setae and 1 plumose seta; dactylus curved.

Pleon 1 with 1 plumose and 1 simple setae ventrally, pleon 2 with 2 ventral and 1 posteroventral plumose setae ( Fig. 9 View FIGURE 9 A). Pleopod 3 shortest ( Fig. 9 View FIGURE 9 B–D); peduncles of pleopods each with a few plumose setae and 2 coupling hooks; outer rami shorter than inner, outer rami of pleopods 2, 3 with 8 and 7 articles and inner rami of pleopods 1–3 with 7, 7 and 6 articles, respectively. Uropod 1 ( Fig. 9 View FIGURE 9 E) with peduncle bearing 3 robust setae on dorsal surface; outer ramus shorter than inner, both rami each with 1 marginal and 4 terminal robust setae. Uropod 2 ( Fig. 9 View FIGURE 9 F) with peduncle bearing 3 dorsal robust setae; outer ramus shorter than inner, both rami each with 1 marginal and 4 terminal robust setae. Uropod 3 ( Fig. 9 View FIGURE 9 G, H) with peduncle bearing distal robust seta on medial margin; ramus short, distal end obtuse, with 2 thick and 2–3 normal setae. Telson ( Fig. 9 View FIGURE 9 H) short, not coalesced with urosomite 3; dorsodistal margin with a pair of simple and penicillate setae.

Female [based on allotype, 2.4 mm (OMNH-Ar-7755)]. Generally similar to male except for antenna 2, gnathopods and oostegites. Antenna 2 ( Fig. 9 View FIGURE 9 I) with peduncular article 4 slender, article 1 of flagellum without excavation. Gnathopod 1 ( Fig. 9 View FIGURE 9 J) with coxal plate smaller than that of male, posteroventral corner rounded. Gnathopod 2 ( Fig. 9 View FIGURE 9 K) with coxal plate roundish-square, bearing several ventral setae and 1 posterior robust seta; basis bearing 4 setae on anterior margin, posterior margin with 2 long setae, posterodistal corner with 3 setae; merus relatively long, distal end truncate; carpus roundish triangular, anterior margin and posterodistal corner setose; propodus setose anteriorly and posteriorly, palm oblique, defined by small robust seta; dactylus relatively stout; oostegite on gnathopod 2 small, with single long seta.

Shape change in male gnathopod 2 with growth. Paratype, 2.2 mm (OMNH-Ar-7756): propodus narrower than that of the holotype, distal margin with small spine ( Fig. 9 View FIGURE 9 L). Paratype 1.7 mm (OMNH-Ar-7757): propodus narrower than that of OMNH-Ar-7756, posterior process short, distal margin with blunt projection posteriorly, dactylus stout ( Fig. 9 View FIGURE 9 M).

Etymology. Referring to the type locality.

Remarks. This new species is characterized by the swelled peduncular article 4 of antenna 2 and the wide propodus of gnathopod 2 in adult male, and shares these characters with Kamaka poppi and K. taditadi . However, K. poppi has the following characters ( Bamber, 2003): (1) peduncular article 4 of male antenna 2 with distal spine (absent in K. songkhlaensis ), (2) merus of male gnathopod 2 long (relatively short in K. songkhlaensis ), (3) distal margin of propodus of male gnathopod 2 almost straight (convex in K. songkhlaensis ), (4) carpi of male pereopods 3, 4 short (relatively long in K. songkhlaensis ), (5) inner rami of uropods 1, 2 without marginal spine (present in K. songkhlaensis ). On the other hand, K. taditadi has the following characters ( Thomas & Barnard, 1991; Krapp-Schickel & Myers, 2006): (1) posteroventral corner of male coxa 1 round (right-angled in K. songkhlaensis ), (2) merus and carpus of male gnathopod 2 long (relatively short in K. songkhlaensis ), (3) anterior margin of propodus of male gnathopod 2 with blunt triangular process (absent in K. songkhlaensis ). In addition, the new species inhabits brackish environment, whereas K. taditadi is a marine species.

Distribution. Outer Songkhla Lagoon (present study), Middle Songkhla Lagoon ( Angsupanich et al., 2005) and Upper Songkhla Lagoon ( Ruensirikul et al., 2007).