Aphantolana wandoor, Anil & Jayaraj, 2020

Anil, Pathan & Jayaraj, K. A., 2020, A new species of Aphantolana Moore & Brusca, 2003 (Crustacea: Isopoda Cirolanidae) from the Andaman Islands, northern Indian Ocean, Zootaxa 4860 (4), pp. 541-552 : 542-550

Aphantolana wandoor sp. nov.

( Figs 2–5 )

Metacirolana sp.— Anil, Ameen, Bijin Mohammad & Jayaraj 2020:155–161.

Material examined: Holotype: ♂ (2.4 mm), South Andaman , Wandoor, 11°22’06’’N; 092°40’33’’ E, 17 Septem- ber 2016, hand collection on intertidal algae, coll. Pathan Anil ( PUMB 3531 ).

Paratypes: 7♂ (2.0, 2.0, 2.1, 2.3, 2.3 [dissected], 2.3, 2.4 mm), 5♀ (2.1, 2.1, 2.2, 2.3, 2.3 mm, [one 2.3 mm dissected]), same data as holotype ( PUMB 3532 ) . 4♂ (2.1, 2.2, 2.2, 2.4 mm), 6♀ (2.2, 2.2, 2.3, 2.3, 2.3, 2.4 mm),

South Andaman, Chidiyatapu, 11°29’55’’ N; 092°42’50’’ E, 19 September 2016, hand collection on intertidal algae, coll. Pathan Anil. 3♂ (2.2, 2.2, 2.4 mm), 8♀ (2.0, 2.0, 2.0, 2.2, 2.2, 2.4, 2.5, 2.5 mm), South Andaman , Manjeri , 11°58’33’’N and Lon 92°66’67’’E, 20 September 2016, hand collection on intertidal algae, coll. Pathan Anil. 1♂ (2.3mm), 8♀ (1.9, 2.0, 2.1, 2.1, 2.3, 2.4, 2.5, 2.5 mm), South Andaman , Kodiyaghat , 11°31.699’N, 92°43.432’E, 7 November 2016, hand collection on intertidal algae. coll. Pathan Anil. [Specimens previously reported by Anil et al. (2020).]

Description. Body 2.5 times as long as greatest width, dorsal surface smooth, widest at pereonite 5, lateral margins subparallel. Cephalon rostral point present; eyes separated by about 30% width of head, eye colour brown; interocular area with brown coloured line. Pereonite 1 and coxae 2–4 each with posteroventral angle acute; coxae 5–6 posteroventral angle slightly rounded; coxae 2–7 with entire oblique carina; coxae 7 posteroventral angle broadly rounded, extending to pleonite 5. Pleon with pleonite 1 visible in dorsal view, posterolateral angles pointed, hidden slightly below coxa 7; pleonites 3–5 posterior margin smooth; pleonite 2 posterolateral angles, pleonite 3 posterolateral margins not extending to posterior margin of pleonite 5, moderately rounded; pleonite 4 posterolateral margin broader, rounded and extending beyond posterior margin pleonite 5; pleonite 5 widest with posterolateral angles overlapped by lateral margins of pleonite 4. Pleotelson sub-triangular in shape, 0.6 times as long as anterior width; with 3 smooth longitudinal carina; anterior lateral margins slightly convex; posterior lateral margins slightly concave; posterior margin moderately rounded, smooth with 2 RS and 4 plumose setae.

Antennula peduncle article 11.5 as long as wide, 1.1 as long as article 2; article 31.4 as long as wide; flagellum with 5 articles, extending to posterior margin of the cephalon. Antenna peduncle article 4 2.2 as long as wide, 1.5 as long as article 3, and 6 long simple setae and 1pappose seta (superior margin distally); article 51.4 as long as article 4, 4.4 as long as wide, dorsal margin with 5 pappose setae and 10 simple short setae; flagellum with 10 articles, extending to posterior of pereonite 1.

Frontal lamina anteriorly rounded, anterior margin projecting; overlapping basal articles of antennula, lateral margin concave narrowing strongly to posterior.

Mandible molar process anterior margin with 14 flat teeth; spine row composed of 8 spines; palp article 2 with 7 fringed setae, palp article 3 with 5 fringed setae. Maxillula mesial lobe with 1 small apical spine in addition to the 3 CPS; lateral lobe with 10 RS many strongly barbed. Maxilla lateral lobe with 3 long simple setae; middle lobe with 3 long simple setae; mesial lobe with 4 distal simple setae and 1 plumose seta. Maxilliped palp article 2 mesial margin with 1 fringed seta and 1 slender seta, lateral margin distally with 1 slender seta; article 3 mesial margin with 4 fringed setae, lateral proximal margin 1 slender seta and distally with 3 slender setae; article 4 mesial margin with 3 fringed setae; article 5 distal margin with 2 fringed setae and 2 slender setae; endite with 3 CPS and 1 coupling seta.

Pereopod 1 basis 3.3 as long as greatest width, inferior distal margin with 1 long seta; ischium 1.1 as long as basis, inferior medial margin with 3 bluntly rounded RS, dorsal posterior margin with 1 short seta, superior distal margin with 1seta; merus inferior proximal margin with 2 rounded connate spines, 1 short seta, distal margin with 1 simple seta and 1 denticulate spine, superior distal margin with 1 seta; carpus inferior distal margin with 1 denticulate spine and 1 long seta; propodus 2 times as long as wide, inferior proximal margin with two tooth shaped nodules, 1 non denticulate spine, 1 large multidenticulate spine and 2 simple short setae; dactylus dorsal posterior region with 3 setae.

Pereopod 2 ischium superior distal margin with 1 seta; merus inferior medial margin with 3 compound spines, distally 1 long seta, 1 slender spine and 1 stout denticulate spine, superior distal margin with 1 denticulate spine and 2 slender setae; carpus superior margin lacking free space, inferior distal margin with 2 stout spines and 1 long seta; propodus 2.4 as long as wide, inferior margin with 1 stout spine, 1 small denticulate spine, 1 large multidenticulate spine and 1 fringed seta, superior distal margin with 2 short setae; dactylus dorsal posterior margin with 2 setae, a small spine base of the dactylus claw.

Pereopod 3 merus inferior margin with 5 small rounded tubercles, 3 large rounded compound spines and distally 1 slender compound spine; carpus inferior distal margin with 2 slender compound spines; propodus inferior margin with 1 slender compound spine and distally 1 large serrated spine, dactylus slender.

Pereopod 4, ischium, merus and carpus superior distal margins with tooth like spines and inferior distal margins of ischium, merus, carpus and propodus have slender compound spines.

Pereopod 5 similar to pereopod 4. Pereopods 6 similar to pereopod 7.

Pereopod 7 basis 3.3 as long as greatest width, ischium superior distal margins with 1 serrated spine, 1 denticulate spine and 1 slender spine; merus superior distal margins with 4 denticulate spines; superior distal margins of carpus with densely occupied serrated spines; inferior margins of ischium, merus, carpus and propodus have slender compound and denticulate spines.

Penes twice as long as wide, separated by about their diameter.

Pleopods exopods 1–5 wider than endopods. Pleopod 1 exopod 1.7 as long as wide, lateral margin straight, distally narrowly rounded with strongly oblique medial margin with 19 PMS, endopod with 6 PMS; peduncle 0.9 as wide as long, mesial margin with 3 coupling setae. Pleopod 2 exopod with 19 PMS, endopod with 8 PMS; appendix masculina proximally wider and distally narrow with triangle acute apex, extending just beyond endopod. Pleopod 3 exopod with 19 PMS, endopod with 4 PMS. Pleopod 4 exopod with 21 PMS, endopod with 4 PMS. Pleopod 5 exopod with16 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS. Exopod of pleopods 3, 4 and 5 with complete medial transverse incision.

Uropod peduncle ventrolateral margin with 2 RS. Endopod reaching posterior region of pleotelson apex, inner margin slightly convex with 2 RS, 9 plumose setae; posterior margin with a setal notch with 5 simple setae, 2 plumose setae; outer margins with 4 short setae anteriorly, 2 plumose setae posteriorly; dorsal surface of the endopod bearing 4 plumose sensory setae. Exopod not extending to end of endopod, exopod inner margins slight convex with 3 plumose setae, posterior margin smooth, slightly sinuate with 2 RS, 2 plumose setae and 2 short simple setae, posterior lateral margins with slight concavity, medial region with 2 short RS; dorsally many short setae present.

Female. Similar to the male, except with slight inter ocular depression of cephalon. Pleotelson posterior lateral margin slightly straighter, uropodal endopod mesial distal margin with 1 robust seta.

Remarks. Aphantolana wandoor sp. nov. can be immediately identified by the concave posterior lateral margins of the pleotelson and uropodal exopod, also the uropod exopod lateral margin lacks plumose setae and has an evenly rounded posterior margin, slightly sinuate with 2 robust setae, while the mesial lateral margin is slightly convex; the uropodal endopod dorsal surface has 4 plumose sensory setae. Coxae 2–4 have an acute posteroventral angle; while those of 5 and 6 slightly rounded; coxae 2–7 each have an entire oblique carina.

Aphantolana wandoor sp. nov. is effectively the second species of the genus known from the Indian Ocean as Stebbing (1905) figured a male specimen from Galle, Sri Lanka under the name Hansenolana sphaeromiformis ( Hansen, 1890) . Müller & Salvat (1993) clearly showed that Stebbing’s (1905) record was a misidentification, Stebbing’s (1905) figures are excellent, and we have no doubt that the species belongs in Aphantolana , as far as Stebbing’s figures, and until described in full should be regarded as Aphantolana sp. Aphantolana wandoor sp. nov. differs from the Sri Lankan species in having a more elongate body (2.5 as long as greatest width vs 1.8 in Aphantolana sp.) and in having both the uropodal endopod and exopod with evenly convex lateral margins (vs angled in Aphantolana sp.) and setae on the distal three-quarters of the uropodal exopod lateral margin (vs setae on distal half only).

Aphantolana wandoor sp. nov. differs from Aphantolana costaricensis in pereonite 7 lacks short rounded process on the posterolateral margins, pleonite 1 is not overlapped laterally by pereonite 7, lack of a large median tubercle on posterior margin of pleonite 5 and lack of a tubercles on the pleotelson dorsal surface carinae (see Brusca et al. 1995). Aphantolana wandoor sp. nov. differs from A. moortgati in the uropodal exopod mesial margin being weakly convex with 3 plumose setae, posterior margin smooth, slightly sinuate with 2 robust setae, inner outer margin with 2 short robust setae and outer posterior lateral margin with slight concavity (vs both the inner and outer margins of the exopod with two shallow concavities in which a short compound spine is situated, posterior margin slightly concave, bearing some slender simple setae in A. moortgati ) and endopod mesial distal margin with 2 compound robust setae, dorsal surface outer of endopod bearing 4 feathered sensory setae (vs inner distal margin of endopod 3 compound robust setae and dorsal surface of the endopod bearing 7 feathered sensory setae in A. moortgati ) and pleotelson apex 4 plumose setae (vs pleotelson apex 4 short simple setae in A. moortgati of Müller & Salvat 1993). Aphantolana wandoor sp. nov. also differs from Aphantolana sphaeromiformis in having concave pleotelson posterior lateral margins (vs they are straight in specimens of A. sphaeromiformis from the Caribbean and Martinique, French Antilles, specimen of Hansen 1890; Menzies & Glynn 1968; Kensley & Schotte 1989; Müller & Salvat 1993).

Aphantolana wandoor sp. nov. is somewhat similar in appearance to some species of the genus Metacirolana Kussakin, 1979 sharing some similar characters with this genus such as a short antenna, dorsal surface with three longitudinal dorsal carinae on the pleon and pleotelson, but pereonite 1 is longer than others, pereopods 1–3 propodal palm with complex setae and connate spines, pleonite lateral margins covered by the seventh coxal plate exclude Aphantolana wanoor sp. nov. from the genus Metacirolana .

Distribution. Known only from the type locality, South Andaman, Andaman Islands.

Etymology. Named after the type locality.

Figures

FIGURE 2. Aphantolana wandoor sp. nov., holotype ♂ (2.4 mm, PUMB 3531). A, dorsal view; B, coxal plates 1–7; C, anten- nula; D, antenna; E, frontal lamina; F, penes; G, pleotelson; H, uropods.

FIGURE 3. Aphantolana wandoor sp. nov., holotype ♂ (2.4 mm, PUMB 3531). A, pleonites 1–5; B, maxilla; C, maxillule; D, mandible; E, maxilliped.

FIGURE 4. Aphantolana wandoor sp. nov., holotype ♂ (2.4 mm, PUMB 3531). A, pereopod 1; B, pereopod 2; C, pereopod 4; D, pereopod 7.

FIGURE 5. Aphantolana wandoor sp. nov., holotype ♂ (2.4 mm, PUMB 3531). A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod 4; E, pleopod 5.