Floresorchestia odishi Bhoi, Patro and Myers, 2024

Bhoi, Gitanjali, Myers, Alan A., Kumar, R. Kiran & Patro, Shesdev, 2024, A new species of the genus Floresorchestia (Crustacea, Amphipoda, Talitridae) from Chilika Lagoon, east coast of India, Zootaxa 5493 (5), pp. 590-598 : 592-593

Floresorchestia odishi Bhoi, Patro and Myers sp. nov.

( Figs. 2–4 )

Type materials: Holotype: male 13.0 mm, ( ZSI/EBRC/Cr15607 ), intertidal zone of Chilika Lagoon , Rambha (19°30’49.9”N, 85°05’50.4”E), Odisha, India, 04/06/2023, Coll. Gitanjali Bhoi.

Paratypes: ZSI / EBRC / Cr15608 , 1 male, 10.2 mm, ZSI / EBRC / Cr15609 , 1 male, 12.1 mm, ZSI / EBRC /Cr 15610 , 1 female, 9.0 mm, same data as holotype .

Type locality: Samples were collected from seaweed vegetation from Rambha (19°30’49.9”N, 85°05’50.4”E), southern sector of Chilika Lagoon, Ganjam , Odisha.

Habitat: The species lives on seaweed vegetation, Rambha, southern sector of Chilika Lagoon.

Etymology: The species is named based on a classical dance form “Odishi” of Odisha state, where the species is first reported.

Description: Based on male holotype, 13.0 mm

Head: Eyes small, (¼ part of the head). Antenna 1 long, exceeding the end of peduncular article 4 of antenna 2, flagellum with four articles; Antenna 2 slender, peduncular article 5 slender and slightly longer than article 4, flagellum with 18 articles. Maxilla 1, inner plate slender with two plumose setae on the apex, eight-dentate spines on the apex of outer margin, palp 1 articulated; Maxilla 2, inner plate slightly shorter than the outer plate; Maxilliped, inner plate having three stout spines with plumose setae on the apex and margin, outer plate with double rows of apical setae, palp article 2 with distomedial lobe covered with numerous setae, article 4 reduced, button shape; Labium bilobate and covered with small setae on the apex; Left mandible lacinia mobilis four-dentate, molar process strong, incisor four-dentate.

Pereon: Gnathopod 1 sexually dimorphic, deeply subchelate, length ratio of the articles from basis to dactylus is 3.5:1.2:1.8:2.5:2.3:1, basis slender, two setae present on the posterior margin, ischium has one robust seta on the posterodistal corner, lobe present on merus, carpus and propodus covered with palmate setae, carpus 1.5 × longer than propodus, anterior margin with four groups of coupled setae and lobe present on the posterior margin, propodus subtriangular, anterior margin with three groups of coupled setae, posterior margin with well-developed lobe, palm covered with five robust setae and a few small setae, dactylus simple and shorter than palm. Gnathopod 2 sexually dimorphic, subchelate, length ratio of the articles from basis to dactylus is 9.2:2:1.8:1:10.8:10, basis anterior margin smooth, posterior margin with six setae, ischium and merus have a pair of robust setae in their posterodistal corner, carpus triangular and reduced, enclosed by merus and propodus, posterior lobe absent, propodus subovate, 1.3 × as long as wide, palm reaching 39% of the posterior margin of propodus, anterior margin clean, palm lined with robust setae, posterodistal corner with groove, posteromedial surface of propodus with groove, with cuticular patch at corner of palm, dactylus longer than palm, attenuated distally. Pereopod 3, length ratio of the articles from basis to dactylus is 4.9:1.4:3.1:2.6:2.9:1, anterior margin of basis lined up with seven setae and posterior margin with five groups of coupled setae, merus longer than carpus and propodus, anterior and posterior margin covered with clusters of setae in merus, carpus and propodus, dactylus cuspidactylate. Pereopod 4 smallest among all pereopods, length ratio of the articles from basis to dactylus is 3.8:1:2.5:2:2.2:1.2, basis longest with three groups of coupled setae on posterior margin, merus having robust setae on both anterior and posterior margins, carpus anterior margin clean and posterior margin having cluster of setae, propodus with robust setae on both anterior and posterior margins, dactylus amplidactylate. Pereopod 5, length ratio of the articles from basis to dactylus is 4.1:1:2:2.7:3.2:1.2, basis posterior margin serrated with small setae, anterior margin with cluster of setae, merus and carpus distally expanded, propodus slender, longer than carpus and merus, dactylus cuspidactylate. Pereopod 6, length ratio of the articles from basis to dactylus is 3.6:1:2.7:3:3.5:1.2, basis posterior margin serrated with small setae and anterior margin with 12 setae, ischium shortest, merus expanded distally, anterior margin lined with four stout setae and posterior margin with cluster of setae, dactylus simplidactylate. Pereopod 7, length ratio of the articles from basis to dactylus is 5.3:1:3.9:4.4:5.3:2.5, basis longer than broad, posterior margin serrated with minute setae, merus and carpus both expanded distally, dactylus simplidactylate.

Pleon: Pleopods well developed, Epimera 2 and 3 each with slits, epimeron 2 with 43–47 slits and epimeron 3 with 21–24 slits, epimera 1–3 posteroventral corner slightly pointed, posterior margin of epimeron 1 with couple setae and epimeron 3 with four setae. Uropod 1, peduncle with 12 setae in two rows, both the rami subequal in length and shorter than peduncle, outer ramus without marginal seta and inner ramus with five marginal setae and three apical setae, distolateral robust seta absent. Uropod 2, peduncle with five setae in two rows, outer ramus and inner ramus with two marginal setae on each and 2–3 apical setae. Uropod 3 uniramus, ramus slightly shorter than peduncle, four setae present on the peduncle, apical and marginal setae present on ramus. Telson apically incised with three apical setae and two marginal setae on each lobe.

Female: Gnathopod 1 shallowly subchelate, ischium shortest having two stout setae on the posterior margin, propodus having small lobe with palmate setae. Gnathopod 2 mitten-shaped, basis anterior margin expanded and lined up with small setae, palmate setae present on the posterior margin of the propodus and carpus; Oostegites with simple-tipped setae.

Remarks: Currently, the genus Floresorchestia consists of 29 species ( Horton et al. 2023). According to Bichang’A et al. (2021), the genus Floresorchestia can be uniquely identified by the presence of epimeral slits which are present either on epimera I–III, II, or II–III. However, the epimera of two species F. xueli Tong & Hou, 2021 and F. vitilevana (J.L. Barnard, 1960) are without slits and hence needs to be re-evaluated. Further, Lowry & Springthorpe (2019) transferred two species, F. pectenispina ( Bousfield, 1970) and F. serejoae Lowry & Springthorpe, 2015 to a separate genus Austropacifica . This leads to the current species number in the genus to 25. Floresorchestia odishi sp. nov. differs from rest of the 25 species of Floresorchestia in several character states.

Floresorchestia odishi sp. nov. differs from F. amphawaensis Suklom, Keetapithchayakul, Abdul Rahim & Wongkamhaeng, 2022 , F. andrevo Lowry & Springthorpe, 2015 , F. anpingensis Miyamoto & Morino, 2008 , F. boonyanusithii Wongkamhaeng, Dumrongrojwattana & Pattaratumrong, 2016 , F. buraphana Wongkamhaeng, Dumrongrojwattana & Pattaratumrong, 2016 , F. floresiana ( Weber, 1892) , F. kalili Lowry & Springthorpe, 2015 , F. kongsemae Suklom, Danaisawadi & Wongkamhaeng, 2021 , F. laurenae Lowry & Springthorpe, 2015 , F. mkomani Bichang’a & Hou 2021, F. oluanpi Lowry & Springthorpe, 2015 , F. palau Lowry & Myers, 2013b , F. papeari Lowry & Springthorpe, 2015 , F. pohnpei Lowry & Myers, 2013b , F. pongrati Suklom, Keetapithchayakul, Abdul Rahim & Wongkamhaeng, 2022 , F. poorei Lowry & Springthorpe, 2009 , F. seringat Lowry & Springthorpe, 2015 , F. yap Lowry & Springthorpe, 2015 and F. yehyuensis Miyamoto & Morino, 2008 by the number of slits on the epimeral plates. The number of slits on the epimeron 2 for all the above 19 species is less than 40, whereas it is more than 40 in F. odishi sp. nov.

In F. malayensis ( Tattersall, 1922) , the uropod 3 peduncle has a single seta whereas there are four setae in F. odishi sp. nov. Uropod 3 ramus is lacking marginal setae in F. anoquesana ( Bousfield, 1971) , F. samoana ( Bousfield, 1971) and F. hanoiensis Hou & Li, 2003 whereas it is present in F. odishi sp. nov. In F. thienemanni ( Schellenberg, 1931) , antenna 1 reaches the end of peduncular article 4 of antenna 2, whereas in F. odishi sp. nov., antenna 1 extends beyond peduncular article 4 of antenna 2.

Floresorchestia odishi sp. nov. is very close to F. anomala ( Chevreux, 1901) from which it differs in a number of ways. In the male gnathopod 1, the palmate lobe on the carpus and propodus is relatively narrow (vs. broad in F. anomala ); the basis of pereopod 7 is longer than broad (vs. broader than long in F. anomala ). Epimeron 2 and epimeron 3 have 43–47 slits and 21–24 slits, respectively (vs. 28 slits and 19 slits, respectively in F. anomala ).

According to the generic characters described by Lowry & Springthorpe (2015), the pereopods 3– 7 of Floresorchestia are cuspidactylate. However, in F. odishi sp. nov., the pereopods 6 and 7 were found as simplidactylate.

With the inclusion of F. odishi sp. nov., the total global species count within the genus Floresorchestia now stands at 26. In India, this genus is represented by a total of three species.

Figures

FIGURE 2. Floresorchestia odishi sp. nov., male holotype, 13.0 mm, ZSI/EBRC/Cr15607, whole body; male paratype, 10.2 mm, ZSI/EBRC/Cr15608, Maxilla 1, Maxilla 2, Maxilliped, Mandible, Labium, Uropod 1–3 and Telson; female paratype, 9.0 mm, ZSI/EBRC/Cr15610, Oostegites. Scale bars: a—1 mm (body), b—0.2 mm (Mx1, Mx2, Lab, Mxp, Md, T), c—0.5 mm (U1, U2, U3, Ostg).

FIGURE 3. Floresorchestia odishi sp. nov., male paratype, 10.2 mm, ZSI/EBRC/Cr15608, female paratype, 9.0 mm, ZSI/ EBRC/Cr15610. Scale bar: a—1 mm (G1 and G2 of male and female), b—0.1 mm (magnified view of dactylus of female G1).

FIGURE 4. Floresorchestia odishi sp. nov., male paratype, 10.2 mm, ZSI/EBRC/Cr15608. Scale bar: a—1 mm (P3–P7 and Ep1–3), b—0.2 mm (magnified view of dactylus of P3 and P4).