Lobatoradarea kagoshimensis Ariyama & Kodama, 2025

Lobatoradarea kagoshimensis Ariyama & Kodama , sp. nov.

[New Japanese name: Kagoshima-udenaga-yokoebi]

( Figs 17–21)

Type material. Holotype: ovigerous female, 5.1 mm (OMNH-Ar-13222), Kagoshima Bay, off Yojirō, Kagoshima City , Kagoshima Prefecture, 31°33'27"N, 130°33'49"E ( Fig. 1I), 21–23 m depth, fish reef on sandy-mud bottom, using bait trap, 6 August 2021, coll. Midori Matsuoka. GoogleMaps Paratypes: ovigerous female, 5.1 mm (OMNH-Ar-13223, not dissected), ovigerous female, 4.2 mm (OMNH-Ar-13224), 2 females, 4.3, 3.6 mm (OMNH-Ar-13225, 13226), 3 males, 4.0, 3.9, 3.7 mm (OMNH-Ar-13227–13229), same data as holotype GoogleMaps .

Type locality. Off Yojirō , Kagoshima City in Kagoshima Prefecture, Japan .

Etymology. Referring to the type locality.

Description of female. Based on holotype, ovigerous female, 5.1 mm (OMNH-Ar-13222), and paratype, ovigerous female, 4.2 mm (OMNH-Ar-13224) for antenna 2.

Head ( Figs 17, 18). Rostrum strongly developed, lateral cephalic lobe roundish-angular, anteroventral corner moderately projected. Eyes large (diameter: 47% of head height). Antenna 1, peduncular articles 1–3 with length ratio of 1.0: 0.8: 0.2; accessory flagellum very short, cone-shaped, with 5 setae; primary flagellum with 27+ articles, tip lost, article 1 long, 8 articles with aesthetasc. Antenna 2, peduncular articles 3–5 with length ratio of 1.0: 2.4: 3.1, each article bearing several robust setae; flagellum, most part lost, article 1 long. Upper lip relatively long, produced ventrally, anterior surface and ventral margin with many minute setae. Mandibles, both incisors with 7 cusps, laciniae mobilis 8- and 3-toothed in left and right, respectively, both accessory setal rows with 4 thick setae; palp stout, article length ratio 1.0: 3.5: 2.1 in left, article 1 short, bare, article 2 long, with 3–4 setae subdistally, article 3 bearing 1 proximal, 8 ventral and 2 thick and 2 slender distal setae, lateral surface covered with dense thin setae. Lower lip, inner lobes developed, bare; outer lobes with relatively long mandibular lobes, setose mediodistally, ventrodistal surfaces and lateral margins with sparse fine setae. Maxilla 1, inner plate pear-shaped, medial margin bearing long plumose setae, tip with a long thick seta; outer plate distally with 11 denticulate robust setae and 7 thick setae; palp article 1 bare, article 2 apically with 6 triangular and 1 long robust setae and 4 slender setae in left and 7 narrow robust setae and 4 slender setae in right. Maxilla 2, inner plate ca. 1.5 times width of outer plate. Maxilliped, inner plate with 3 triangular robust setae distally; outer plate bearing 5 long and 12 short robust setae mediodistally; palp article 3 dorsal surface with 4 thick setae and many fine setae.

Pereon ( Figs 17, 19). Pereonite 7 not projected posterodorsally. Gnathopod 1 small; coxa subrectangular, with 2 small notches each on anteroventral and posteroventral margins, medial surface bearing several setae; basis slender, straight, anterior margin lined with short setae, posteroproximal margin bearing 4 long setae, lateral and medial surfaces setose; merus acutely projected distally, with several thick setae on posterodistal margin; carpus relatively long, posterior margin bearing many thick setae; propodus slightly shorter than carpus (ca. 0.9 times), posterior margin with several thick setae, palm weakly oblique, defined by 3 (1 lateral and 2 medial) short robust setae; dactylus short. Gnathopod 2 much longer than gnathopod 1; coxa roundish rectangular, with 1 and 2 small notches on anteroventral and posteroventral margins, respectively, medial surface bearing 5 setae; basis slender, straight, anterior margin with a few short setae, posterior margin bearing 1 long and 2 short setae; merus acutely projected distally, posterior margin with a few setae; carpus long and narrow, posterior margin bearing several bundles of slender setae; propodus longer than carpus (ca. 1.2 times), narrow, anterior margin lined with short setae, posterior margin bearing many bundles of slender setae, palm weakly oblique, defined by 4 (2 lateral and 2 medial) short robust setae; dactylus short. Pereopod 3 shorter than gnathopod 2; coxa roundish rectangular, with 3 and 1 small notches on anteroventral and posteroventral margins, respectively, medial surface bearing many setae; basis slightly curved anteriorly, anterior margin with 3 robust setae, posteroproximal margin with 4 slender setae; merus anterodistal corner with a long robust seta; carpus posterior margin with 5 robust setae; propodus longer than carpus, posterior margin with 5 robust setae; dactylus with a minute projection on inner margin. Pereopod 4 almost same length as pereopod 3; coxa ventral margin rounded, with 5 and 3 small notches on anteroventral and posteroventral margins, respectively, medial surface bearing many setae; basis slightly curved anteriorly, anterior margin with 2 robust setae, posteroproximal margin with 4 slender setae; ischium–dactylus similar to those of pereopod 3. Pereopod 5, coxa anteroventral and posterior margins with 3 and 5 small notches, respectively; basis longish ovoid, anterolateral ridge indistinct, anterior margin with many proximal setae and 4 robust setae, anterodistal corner bearing 2 robust setae, posterior margin serrated, medial surface with vertical ridge bearing a robust seta; ischium with a robust seta at anterodistal corner; merus–dactylus lost. Pereopod 6, coxa anterior margin straight, with a seta, posteroventral margin with 6 small notches; basis longish ovoid, with anterolateral ridge, anterior margin with many proximal setae and 4 robust setae, anterodistal corner bearing a robust seta, posterior margin serrated, medial surface with vertical ridge bearing a robust seta; ischium with a slender seta at anterodistal corner; merus with 1+2+2+2 anterior, 2 anterodistal, 3 posterior and 2 posterodistal robust setae; carpus–dactylus lost. Pereopod 7, coxa short, oval, posteroventral margin with 3 small notches; basis ovoid, with anterolateral ridge, anterior margin with many proximal setae and 4 robust setae, anterodistal corner bearing a robust seta, posterior margin serrated, medial surface with short vertical ridge bearing a robust seta (damaged); merus with 1+1+2 anterior, 3 anterodistal, 4 posterior and 3 posterodistal robust setae; carpus–dactylus lost.

Pleon ( Figs 17, 20). Pleonites 1, 2 acutely projected posterodorsally. Epimeral plates 1–3, posteroventral corners minutely produced in plates 1, 3 and strongly produced in plate 2, lateral surfaces with ridge in plates 1, 2, ventral margins bearing 1 and 2 robust setae in plates 2 and 3, respectively. Pleopods, pleopod 2 longest; each peduncle bearing several setae and 2 coupling hooks, peduncles with 1, 2 and 5 robust setae posteromedially in pleopods 1–3, respectively, peduncle of pleopod 3 also bearing a lateral robust seta; outer rami with 14 articles, inner rami with 15, 14 and 12 articles, respectively. Uropod 1, peduncle long, dorsal surface with 6 lateral, 1 laterodistal, 5 medial and 1 mediodistal robust setae, ventrodistal end slightly produced; outer ramus damaged, with 2+ (1 lost) lateral robust setae; inner ramus ca. 0.9 times as long as peduncle, with 3 lateral, 3 medial and 4 terminal robust setae. Uropod 2 about 0.9 times as long as uropod 1; peduncle short, with 3 lateral, 1 laterodistal, 1 medial and 1 mediodistal robust setae, ventrodistal end slightly produced; outer ramus ca. 0.75 times length of peduncle, with 2 lateral and 4 (1 lost) terminal robust setae; inner ramus ca. 2.2 times as long as outer ramus, with 5 lateral, 4 medial and 4 terminal robust setae. Uropod 3 about 0.9 times length of uropod 2; peduncle very short, longer than wide, ventrodistal end acutely produced, dorsal and ventral surfaces with several setae, posterodistal corner bearing a seta; outer ramus ca. 1.65 times length of peduncle, with 4 lateral and 3 medial robust setae; inner ramus about 1.6 times as long as outer ramus, with 8 (2 lost) lateral and 11 medial robust setae. Telson small, trapezoidal, distal margin truncated, dorsal surface with pair of 2+1 sensory setae, each lateral margin bearing 4 minute setae.

Description of male. Based on paratype, male, 4.0 mm (OMNH-Ar-13227). Almost similar to holotype, ovigerous female, 5.1 mm (OMNH-Ar-13222) except for oostegites. Gnathopods resembling those of female; but gnathopod 1 coxa with a small notch each on anteroventral and posteroventral corners, basis slightly setose, with medial long seta ( Fig. 20 M-G1), and gnathopod 2 coxa bearing a small notch each on anteroventral and posteroventral corners, propodus posterodistal corner with 3 (2 lateral and 1 medial) short robust setae ( Fig. 20 M-G2).

Coloration in life. Based on paratype, ovigerous female, 5.1 mm (OMNH-Ar-13223, Fig. 21). Head pale orange with orange posterior margin, eyes bright red; pereonites, pleonites and coxae pale orange with orange margins, lateral surfaces of pleonites 1, 2 each with distinct orange mark mid-posteriorly; antennae peduncles pale orange to white with orange distal margins, flagella faintly-orangish white; gnathopods, pereopods, pleopods and uropods faintly-orangish white, but bases and meri of pereopods 5–7 partly orange.

Remarks. Lobatoradarea kagoshimensis sp. nov. is characterized by a combination of the large eyes and the strongly produced posteroventral corner of the epimeral plate 2. This combination is unique in the genus.

Habitat. Fish reef on sandy-mud bottom with a depth of 21– 23 m.

Distribution. Japan: Kagoshima Bay in Kagoshima Prefecture (present study).