Paralomis indica Alcock & Anderson, 1899

Tiwari, Shivam, Padate, Vinay P., Venugopalan, Vishnu K., Cubelio, Sherine Sonia & Takeda, Masatsune, 2022, Paralomis White, 1856 (Crustacea: Decapoda: Anomura) from India, with morphological variability in Paralomis indica Alcock & Anderson, 1899, Zootaxa 5091 (2), pp. 301-329 : 310-325

Paralomis indica Alcock & Anderson, 1899

( Figs. 6–16 , Tab. 1)

Paralomis indica Alcock & Anderson 1899: 15 .—Alcock 1899: pl. 43, fig. 2, 2a.— Alcock 1901: 234.— Ahyong 2010: 108 (list).— Hall & Thatje 2010: 522 (list in Appendix 1).— McLaughlin et al. 2010: 13 (list).

Material examined. One male ( IO /SS/ANO/00001; PCL 91.2 mm, CW 102.4 mm), Bay of Bengal , FORVSS stn 29283, 6.84°N, 93.05°E, 337 m depth, HSDT ( CV), coll. Dr. Usha Parameswaran, 10 December 2011. One male ( IO /SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), Bay of Bengal , FORVSS stn 27924, 17.05°N, 83.30°E, 550 m depth, Expo model trawl net, coll. Dr. R. Raghu Prakash , 2 September 2010. One male ( IO /SS/ANO/00049; PCL 80.9 mm, CW 94.9 mm), one ovigerous female ( IO /SS/ANO/00050; PCL 64.2 mm, CW 74.0 mm), Bay of Bengal , FORVSS stn 29105, 18.83°N, 85.37°E, 614–643 m depth, HSDT ( CV), coll. Dr. Rajeeshkumar M.P., 30 October 2011. One male ( IO /SS/ANO/00051; PCL 81.5 mm, CW 92.2 mm), one ovigerous female ( IO /SS/ANO/00052; PCL 76.1 mm, CW 90.8 mm), Bay of Bengal , FORVSS stn 29116, 10.92°N, 80.36°E, 645–654 m depth, Expo model trawl net, coll. Dr. Rajeeshkumar M.P., 8 November 2011. Two males ( IO /SS/ANO/00053; PCL 74.0 mm, CW 81.2 mm, PCL 73.7 mm, CW 83.4 mm), Bay of Bengal , FORVSS stn 29117, 11.91°N, 80.14°E, 528–777 m depth, Expo model trawl net, coll. Dr. Rajeeshkumar M.P., 9 November 2011. Two males ( IO /SS/ANO/00054; PCL 77.3 mm, CW 83.4 mm, PCL 77.6 mm, CW 88.2 mm), Bay of Bengal , FORVSS stn 27901, 11.10°N, 80.32°E, 645 m depth, HSDT ( CV), coll. Dr. R. Raghu Prakash , 26 August 2010. Two males ( IO /SS/ANO/00055; PCL 54.4 mm, CW 60.7 mm, PCL 65.8 mm, CW 71.6 mm), Bay of Bengal , FORVSS stn 29103, 18.84°N, 85.39°E, 633–655 m depth, Expo model trawl net, coll. Dr. Rajeeshkumar M.P., 29 October 2011. One male ( IO /SS/ANO/00057; PCL 85.9 mm, CW 95.0 mm), Arabian Sea, FORVSS stn 31810, 12.10°N, 74.32°E, 315–326 m depth, Expo model trawl net, coll. Dr. Rajool Shanis C.P., 26 August 2013. One male ( IO /SS/ANO/00059; PCL 82.4 mm, CW 92.5 mm), one female ( IO /SS/ANO/00056; PCL 68.7 mm, CW 70.6 mm), Arabian Sea, FORVSS stn 31801, 12.47°N, 74.15°E, 440–449 m depth, Expo model trawl net, coll. Dr. Rajool Shanis C.P., 24 August 2013. Three males ( IO /SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm, PCL 69.0 mm, CW 74.2 mm, PCL 78.1 mm, CW 80.8 mm), four females ( IO /SS/ ANO/00060; PCL 62.3 , CW 68.1 mm, PCL 67.1 mm, CW 75.1 mm, PCL 67.9 mm, CW 72.9 mm, PCL 70.1 mm, CW 70.0 mm), Arabian Sea, FORVSS stn 39801, 8.24°N, 76.49°E, 610 m depth, Expo model trawl net, coll. Aleesha K. Shaji, 29 February 2020. Four males ( IO /SS/ANO/00120; PCL 79.7 mm, CW 84.9 mm, PCL 61.1 mm, CW 63.7 mm, PCL 66.1 mm, CW 70.6 mm, PCL 59.7 mm, CW 68.9 mm), one female ( IO /SS/ANO/00121; PCL 62.6 mm, CW 65.1 mm) Arabian Sea, FORVSS stn 39901, 8.64°N, 76.10°E, 1065 m depth, coll. Dr. Aneesh Kumar K. V., HSDT ( CV), 23 September 2020. One juvenile male, ( IO /SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), Bay of Bengal, FORVSS stn 27924, 17.05°N, 83.30°E, 550 m depth, coll. Dr. R. Raghu Prakash, Expo model trawl net, 2 September 2010.

Description. Carapace broad, pyriform (PCL 0.8–1.0 CW), lateral margins sinuous, subparallel in most specimens, regularly convex in few specimens; regions distinct ( Figs. 6A–D , 13A, D, G, J , 14A, D, G, J , 15A, D, G, J ). Surface covered with unequal-sized conical tubercles; larger conical tubercles with acuminate apex, surface pitted ( Fig. 6A–D ); elongated tubercles on carapace including 1 at anterior end of branchial region. Gastric region convex, moderately elevated, with 15–17 moderately large conical tubercles, and few minute interspersed tubercles. Lateral margin of hepatic region with 3 alternately large and small conical spines. Branchial anterior margin with 5–8 alternately large and small spines, lateral margin with 4–7 alternately large and small spines, posterior margin with 9–13 small spines; dorsal surface moderately to distinctly inflated, elevation much more prominent than other regions (moderately prominent in few specimens), covered with unequal-sized conical tubercles and randomly scattered minute tubercles. Cardiac region subtriangular, moderately to distinctly depressed, with 2 submedian pairs followed by 1 median short conical tubercle. Intestinal region with 1 median and 1 pair of submedian short conical tubercles. Pterygostomian region sparsely granular, with prominent anterior spine ( Fig. 7A, B ).

Rostrum trispinous, 0.1–0.2 PCL; broadest basally; median spine elongate conical, gently curved upwards, smooth, ventral lobe triangular, covered with granules; dorsal spines subparallel to diverging, shorter than median spine, directed obliquely upwards, tips acuminate ( Fig. 7C, D ). Posterior orbital margin concave, armed with short spine at inner base of outer orbital spine; outer orbital spine slender, directed anteriorly, short of or overreaching apex of cornea. Anterolateral spine slightly shorter than outer orbital spine; distance between the outer bases of anterolateral spines 0.3–0.4 CW.

Ocular peduncle longer than cornea, with randomly scattered spinules, 1 large median conical spinule flanked by 3 spinules laterally and 1 or 2 spinules mesially above cornea ( Fig. 7E, F ).

Antennular peduncle unarmed, reaching anteriorly beyond apex of antennal peduncle by length of distal antennular peduncle article ( Fig. 8A, E, H ).

Basal antennal article with sparsely granular dorsal surface, with large distolateral spine and 1 lateral spinule. Article 2 with sparsely granular dorsal surface, angular outer margin terminating in a sharp spine, with 2 basal spinules; distolateral spine overreaching distal margin of article 4; inner margin terminating in a sharp spine, with 1 subdistal spine; distomesial spine shorter than distolateral, with one blunt basal spine. Article 3 with sparsely scattered setae ( Fig. 8A, E, H ). Scaphocerite a long slender spine not reaching apex of distal peduncular article, most specimens bearing 2 inner and 2 outer spines and 1 inner or 1 outer spinule, dorsal surface with 2 blunt spinules, few others bearing 3 inner and 3 outer spines and 1 blunt spinule ( Fig. 8B–C, F, I ). Article 4 very sparsely setose, less than half length of article 5.

Maxilliped 3 pediform, widely separated basally ( Fig. 8D, G, J ). Ischium with crista dentata consisting of 16 teeth; accessory tooth present. Merus, carpus with single row of setae on mesial margin. Propodus triangular in cross-section, with thick bunches of grooming setae on mesial margin, outer base of triangle with row of setae. Dactylus flattened with thick bunches of grooming setae along mesial margin.

Abdominal somite 2 covered with conical tubercles smaller than those on carapace ( Fig. 9A, C, G, J ). Somites 3–6 arranged almost in a straight line in males ( Figs. 13B, E, H, K , 14B, E, H, K ), curved towards right in females ( Fig. 15B, E, H, K ), covered with conical tubercles progressively smaller in size, margins spinose, bearing acute spines in most specimens, blunt spines in few others; marginal plates narrow to wide, indistinctly to distinctly subdivided. In males, somite 6 1.0–1.2 times longer than wide (0.9 in the juvenile male), marginal plates slightly short of or overreaching distal margin of median plate; in females, 1.0–1.4 times longer than wide. Telson bluntly triangular, slightly wider than long, with 1 submedian pair of short conical tubercles ( Figs. 13B, E, H, K , 14B, E, H, K , 15B, E, H, K ).

Pereopods 1 (chelipeds) unequal, spination similar in both sexes. Major cheliped of males moderately to distinctly inflated ( Fig. 10A–C ), ratio of height of major cheliped and minor cheliped 1.6–2.3 in males, 1.0– 1.9 in females; minor cheliped slender ( Fig. 10D–F ). Coxae smooth to sparsely granular in males, distal margins minutely tuberculate ( Fig. 9B, D, F, H ); in females, coxae smooth, covered with long silky setae ( Fig. 8B ). Ischiobasis sparsely covered with conical spines, longer and numerous in smaller specimens. Merus sparsely covered with conical spines on mesial and lateral surfaces, distal margin of lateral surfaces with 4 short spines; dorsal margins of larger chelipeds in both sexes with 4 strong spines, those of smaller chelipeds with 4 comparatively smaller spines. Carpus dorsal margins with 4 large and 1 small spines, ventral margin with randomly scattered spinules, mesial surface with sparsely placed spinules (longest in smaller specimens), lateral surfaces with 3 irregular rows of well-spaced shorter spines. Propodus with 1 pair of subdistal spines followed by 1 irregular row of spines on dorsal margin, ventral margin with 1 irregular row of small well-spaced spines, mesial surfaces with 2 rows of well-spaced spinules on lower portion, upper portion with irregular patch of spinules, lateral surfaces with 4 rows of well-spaced small spines and 1 or 2 rows of spinules; mesial and lateral surfaces with spines bearing setal tufts anteriorly, extending onto proximal portion of pollex.

Major cheliped 1.0–1.5 PCL in males, 1.0– 1.1 in females; upper palm length 0.9–1.2 times height in males (2.0 in juvenile male), 0.9–1.3 in females; upper palm length 1.3–1.7 times width in males, 1.3–1.5 in females; occlusal margins of fingers corneous for distal one-fourth, proximally with 4 low calcareous nodules, proximal nodule largest; dactylus dorsal margin broadly convex, with rows of tufts of golden setae and 1 large proximal spine ( Fig. 10A–C ), 1.1–1.3 times longer than dorsal margin of palm in males (0.6 in juvenile male), 1.2–1.7 in females.

Minor cheliped 0.9–1.3 PCL in males, 0.9–1.1 in females; upper palm length 0.9–1.2 times height in males (1.2 in juvenile male), 1.0– 1.2 in females; occlusal margin corneous in distal half, proximally crenulate; dactylus dorsal margin broadly convex, with rows of tufts of golden setae and 2–3 small proximal spines ( Fig. 10D–F ), 1.8–2.1 times longer than dorsal margin of palm in males (1.7 in juvenile male), 1.6–1.9 in females.

Pereopods 2–4 similar, elongate, spinose ( Fig. 11A–C, E–G, I–K ). Coxae smooth, very sparsely spinulose, covered with long silky setae, margins bearing tufts of setae. Ischiobases with dorsal surface smooth, sparsely setose, ventral surfaces with proximally setose patch, distal two-thirds with 8–12 randomly scattered short conical tubercles (spines in smaller specimens) bearing a ring of setae around the apex (largest on P4), proximal and distal margins with a row of spinules, anterior and posterior margins with small random tufts of setae. Meri compressed, shorter than carapace in both sexes; extensor margins with 2–6 spinules and 4–6 spines (fewest in smaller specimens), distal margins with 3–4 spines; dorsal surfaces with an irregular row of 3–8 (fewest in smaller specimens) spines and randomly scattered spinules; flexor margins with 2 irregular rows of 4–7 spines (fewest in smaller specimens), ventral surfaces sparsely spinulose; merus of pereopod 3 slightly longer than that of pereopod 2 and pereopod 4. Carpi slightly shorter than to approximately two-thirds meral length, subcircular in cross-section; extensor margins with 5–6 spines; dorsal surfaces with 5–6 spines, and randomly scattered spinules in few specimens; flexor margins sparsely spinulose. Propodi dorsoventrally flattened, shorter than meri, with a distal ring of 5–7 spines; extensor margins with 5–6 spines; dorsal surfaces with 2 rows of 5–6 spines; flexor margins with 5–7 spines, distinct dense setose patch on distal half (in some specimens only on P4); ventral surfaces with 2 irregular rows of 4–7 setose spinules (fewest in smaller specimens). Dactyli broadly curved; slightly longer than extensor margins of propodi; extensor margins with tufts of setae on distal two-thirds to three-fourths, 3 apically corneous spines and a random spinule proximally; lateral proximal surfaces with short, distinct sulcus, flanked ventrally by 1 small, corneous spine; flexor margin lined with 10–12 movable spinules ( Fig. 11D, H, L ).

Pereopod 2 length 1.5–2.5 PCL in males (1.4 in juvenile male), 1.4–1.6 in females. Merus 0.4–0.6 PCL in males (0.4 in juvenile male), 0.4 in females; length: height ratio 2.3–4.5 in males, 2.4–3.1 in females. Carpus 0.6–0.7 merus length in males (0.7 in male juvenile), 0.7 in females. Propodus 0.7–0.9 merus length in males, 0.7–0.8 in females; length: height ratio 3.6–6.6 in males, 3.5–6.1 in females. Dactylus 1.0–1.3 propodus length in males, 1.1–1.3 in females.

Pereopod 3 length 1.5–2.5 PCL in males, 1.4–1.6 in females. Merus 0.4–0.7 PCL in males (0.4 in juvenile male), 0.4 in females; length: height ratio 2.6–4.0 in males, 2.5–3.1 in females. Carpus 0.6–0.7 merus length in males (0.6 in juvenile male), 0.7 in females. Propodus 0.7–0.9 merus length in both sexes (0.9 in juvenile male); length: height ratio 3.6–6.8 in males, 3.4–5.0 in females. Dactylus 1.0–1.3 propodus length in males (0.9 in juvenile male), 1.1–1.3 in females.

Pereopod 4 length 1.4–2.4 PCL in males, 1.4–1.6 in females. Merus 0.4–0.6 PCL in males, 0.4 in females; length: height ratio 2.6–4.2 in males, 2.6–3.3 in females. Carpus 0.6–0.7 merus length in males (0.6 in juvenile male), 0.7 in females. Propodus 0.7–0.9 merus length in males, 0.8–0.9 in females; length: height ratio 3.5–6.0 in males, 3.4–5.0 in females. Dactylus 1.0–1.4 propodus length in males (0.9 in juvenile male), 1.2–1.3 in females.

Morphological variability. The present material of P. indica collected from the southeast Arabian Sea, western Bay of Bengal and southeast Andaman waters (off Great Nicobar Island) exhibited high intraspecific variations (both intersexual and ontogenic) in the form of the carapace and dorsal rostral spines, nature of the branchial and cardiac regions, abdominal marginal spines, and pereopod length: PCL ratios for P2–P4. The present material was classified into 5 geographical regions (Arabian Sea off Trivandrum, Arabian Sea off North Kerala, southwestern Bay of Bengal, northwestern Bay of Bengal and Andaman waters) and 5 size-classes (20–30 mm PCL, 50–60 mm PCL, 60–70 mm PCL, 70–80 mm and 80–90 mm PCL) to infer the morphological and morphometric variations.

In the Trivandrum region, the single male in the 50–60 mm size-class was characterized by convex carapace lateral margins, moderate branchial inflation, protruding cardiac region (in posterior view), V-shaped dorsal rostral spines, prominent abdominal marginal spines and lower PL/PCL ratio (for P2–P4) of 1.5. The 60–70 mm size-class of the males (n = 4) was characterized by convex carapace lateral margins, moderate branchial inflation, protruding cardiac region, V-shaped dorsal rostral spines, prominent abdominal marginal spines and slightly higher PL/PCL ratio of 1.5–1.8 ( Fig. 13A–C ); the females in this size-class (n = 4) differed in the slightly lower PL/PCL ratio of 1.4–1.6. The 70–80 mm size-class of the males (n = 2) was characterized by broadly convex carapace lateral margins, distinct branchial inflation, sunken cardiac region, V-shaped to curved dorsal rostral spines, prominent abdominal marginal spines and PL/PCL ratio of 1.4–2.1 ( Fig. 13D–F ); the single female in this size-class differed in having convex carapace lateral margins, moderate branchial inflation, protruding cardiac region and PL/PCL ratio of 1.5 ( Fig. 15A–C ).

Off North Kerala, the single female in the 60–70 mm size-class was characterized by sinuous carapace lateral margins, distinct branchial inflation, sunken cardiac region, curved dorsal rostral spines, prominent abdominal marginal spines and PL / PCL ratio of 1.4 ( Fig. 15D–F ). The 80–90 mm size-class (2 males) was characterized by convex carapace lateral margins, moderate to distinct branchial inflation, protruding to sunken cardiac region, Vshaped to curved dorsal rostral spines, prominent to short abdominal marginal spines and PL / PCL ratio of 1.9–2.1 ( Fig. 13H–J ) .

In the southwestern Bay of Bengal, the 70–80 mm size-class of the males (n = 4) was characterized by variations in carapace lateral margins (broadly convex to sinuous), branchial inflation (moderate to distinct), nature of cardiac region (protruding to sunken), curved dorsal rostral spines, abdominal marginal spines (prominent to short) and PL/PCL ratio of 1.7–2.3 ( Figs. 13J–L , 14A–C ); the single female in the above size-class possessed sinuous carapace lateral margins, distinct branchial inflation, protruding cardiac region, curved dorsal rostral spines, prominent abdominal marginal spines and PL/PCL ratio of 1.4–1.5 ( Fig. 15G–I ). The single male in the 80–90 size class was characterized by broadly convex carapace lateral margins, moderate branchial inflation, protruding cardiac region, curved dorsal rostral spines, short abdominal marginal spines and PL/PCL ratio of 2.0–2.1.

In the northwestern Bay of Bengal , the single juvenile male in the 20–30 mm size-class was characterized by sinuous carapace lateral margins, moderate branchial inflation, protruding cardiac region, V-shaped dorsal rostral spines, short abdominal marginal spines and PL / PCL ratio of 1.4–1.5 ( Fig. 14J–L ). The single male in the 50–60 mm size-class was characterized by sinuous carapace lateral margins, moderate branchial inflation, protruding cardiac region, V-shaped dorsal rostral spines, short abdominal marginal spines and PL / PCL ratio of 1.7 ( Fig. 14G–I ). The single male in the 60–70 mm size-class was characterized by broadly convex carapace lateral margins, distinct branchial inflation, sunken cardiac region, V-shaped dorsal rostral spines, (abdomen missing) and PL / PCL ratio of 1.9; the single female in the above size-class differed from the male in having sinuous carapace lateral margins, curved dorsal rostral spines, prominent abdominal marginal spines and PL / PCL ratio of 1.4–1.5 ( Fig. 15J–L ). The 80–90 mm size class (2 males) was characterized by sinuous carapace lateral margins, distinct branchial inflation, sunken cardiac region, curved dorsal rostral spines, short abdominal marginal spines and PL / PCL ratio of 2.0–2.3 ( Fig. 14D–F ) .

In the Andaman waters, the single male in the 80–90 mm size-class was characterized by sinuous carapace lateral margins, distinct branchial inflation, sunken cardiac region, curved dorsal rostral spines, short abdominal marginal spines and PL/PCL ratio of 2.4–2.5.

In conclusion:

a. The largest males (80–90 mm) were generally characterized by curved dorsal rostral spines, short abdominal marginal spines and PL/PCL ratio> 1.9.

b. High variability in the morphological characters among the males in the 50–60 mm size-class, as well as both the sexes in the 60–70 mm and 70–80 mm size-classes.

c. All females were characterized by a lower PL/PCL ratio compared to the males in their corresponding sizeclasses.

Genetic data. COI sequence GenBank accession number: MW118601 . 16S rRNA GenBank accession number MW369444 .

Remarks. Paralomis indica was originally described by Alcock & Anderson (1899) from a small-sized juvenile male collected in the southeastern Arabian Sea and illustrated by Alcock (1899: pl. 43, fig. 2, 2a) ( Fig. 12 ); the present study provides the second record of this species to date. This species was defined by “vesiculous, pustulous and conical tubercles of various sizes” on the carapace and a “trifid” rostrum “with a pair of denticles at base”. The holotype deposited in the Zoological Survey of India, Kolkata was not available for comparison despite several requests. The juvenile male (27.1 mm PCL) in the present collection resembles the description and illustrations of the type specimen in possessing the distinctly inflated branchial regions, sunken narrow cardiac region, and the ornamentation on the carapace and abdomen comprising conical tubercles of various sizes, and the shape of the rostrum. It is briefly noted here that the short left pereopod 3 and 4 illustrated by Alcock (1899: pl. 43 fig. 2) ( Fig. 12 ) are surely due to the regeneration after autotomy.

This species differs from all its congeners in having a broad pyriform carapace (approaching a globose shape). The only congeneric species to some extent resembling P. indica is P. danida Takeda & Bussarawit, 2007 from the eastern Andaman Sea. The morphological comparison with the latter species by Takeda & Bussarawit (2007) was based on the type material of P. indica largely comprising juveniles. However, with the availability of large-sized adults (max. 91.2 mm PCL, 102.4 mm CW from the Andaman waters) during the present study, the morphological differences between the two congeners are: (1) broadly pyriform carapace covered with well-spaced larger tubercles in P. indica ( Fig. 6 ) [vs. sub-pentagonal carapace with relatively closely-spaced short, prickle-like tubercles in the latter species ( Takeda & Bussarawit 2007: fig. 2A)]; (2) posteriorly constricted gastric region [vs. posteriorly wide gastric region ( Takeda & Bussarawit 2007: fig. 2A)]; (3) the antennal scaphocerite not reaching the apex of antennal peduncle ( Fig. 8C ) [vs. scaphocerite overreaching in the latter species ( Takeda & Bussarawit 2007: fig. 4C)]; and (4) comparatively less tuberculose abdomen [vs. densely tuberculose abdomen in the latter species ( Takeda & Bussarawit 2007: fig. 3B)].

TABLE 1. Kimura 2 parameter (K2P) pair wise analysis based estimated intra genus genetic variation among COI sequences of species of Paralomis .

TABLE 2. Kimura 2 parameter (K2P) pair wise analysis based estimated intra genus genetic variation among 16S rRNA sequences of species of Paralomis .

Distribution. Southeastern Arabian Sea off Trivandrum at 786 m depth ( Alcock & Anderson 1899), 610 and 1065 m depths (present study), off North Kerala at 326 and 449 m; western Bay of Bengal at 645, 654 and 777 m off Pondicherry, 550, 643 and 655 off Andhra Pradesh coast (present study); Andaman waters off Great Nicobar Island at 337 m (present study). The known geographical range now extends eastwards to the Bay of Bengal and Andaman waters.

Genetic analysis. The maximum likelihood clustering approaches using mitochondrial COI revealed that P. indica is genetically distant from all other species and shows a minimum K2P genetic distance of 11.0% with Paralomis granulosa , and maximum K2P gentic distance of 13.7% with P. ceres . Paralomis ceres shows a minimum K2P genetic distance of 6.8% with P. birsteini and a maximum K2P distance of 12.9% with P. dofleini ( Table 1).

Similarly, the ML tree constructed using 16S rRNA revealed that P. indica is genetically distant from all other species and shows a with minimum K2P genetic distance of 1.9% with Paralomis dofleini , and maximum distance of 3.5% with P. spinosissima . Paralomis ceres is closer to P. anamerae with a minimum gentic distance of 0.9% and a maximum genetic distance of 2.9% with P. zealandica ( Table 2).

Figures

FIGURE 6. Paralomis indica Alcock & Anderson, 1899, dorsal habitus. A, male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India; B, male (IO/SS/ANO/00120; PCL 79.7 mm, CW 84.9 mm), southeast Arabian Sea, India; C, male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India; D, juvenile male (IO/SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal. Inset boxes showing carapace ornamentation. Scale bar: A–C = 50 mm; D = 10 mm.

FIGURE 7. Paralomis indica Alcock & Anderson, 1899. Male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India. A, lateral carapace and pterygostomian flap; C, rostrum; E, ocular peduncle. Male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India. B, lateral carapace and pterygostomian flap; D, rostrum; F, ocular peduncle. Scale bar: A = 50 mm; B = 10 mm; C–F = 5 mm.

FIGURE 8. Paralomis indica Alcock & Anderson, 1899. Male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India. A, antennule, antenna and scaphocerite, ventral view; B, C, scaphocerite enlarged, dorsal view; D, maxilliped 3, ventral view. Male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India; E, antennule, antenna and scaphocerite, ventral view; F, Scaphocerite enlarged, dorsal view; G, maxilliped 3, ventral view. 1 juvenile male (IO/SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal, India; H, antennule, antenna and scaphocerite, ventral view; I, scaphocerite enlarged, dorsal view; J, maxilliped 3, ventral view. Scale bar: A–G = 5 mm; H–J = 2 mm.

FIGURE 9. Paralomis indica Alcock & Anderson, 1899. Male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India:A, posterior part of carapace and second abdominal somite, posterior view; B, sternum and P1–P4 coxae, ventral view. Male (IO/SS/ANO/00120; PCL 79.7 mm, CW 84.9 mm), southeast Arabian Sea, India: C, posterior part of carapace and second abdominal somite, posterior view; D, sternum and P1–P4 coxae, ventral view. Male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India: E, posterior part of carapace and second abdominal somite, posterior view; F, sternum and P1–P4 coxae, ventral view. Juvenile male (IO/SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal, India: G, posterior part of carapace and second abdominal somite, posterior view; H, sternum and P1–P4 coxae, ventral view. Scale bar = 10 mm.

FIGURE 10. Paralomis indica Alcock & Anderson, 1899. Male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India:A, right cheliped (merus, carpus, chela), lateral view; D, Left chela, lateral view. Male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India: B, right cheliped (merus, carpus, chela), lateral view; E, left chela, lateral view. Juvenile male (IO/SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal, India: C, right cheliped (merus, carpus, chela), lateral view; F, left chela, lateral view. Scale bar: A, D = 10 mm; B–C, E = 5 mm; F = 2 mm.

FIGURE 11. Paralomis indica Alcock & Anderson, 1899. Male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India: A–C, P2–P4, dorsal view; D, right P4 dactylus, dorsal view. Male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India: E–G, P2–P4, dorsal view; H, right P4 dactylus, dorsal view. Juvenile male (IO/ SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal, India: I–K, P2–P4, dorsal view; L, right P4 dactylus, dorsal view. Scale bar: A–G, I–K = 10 mm; H = 5 mm; L = 2 mm.

FIGURE 12. Paralomis indica Alcock & Anderson, 1899, line illustration from Alcock, 1899, plate 43, fig. 2, 2a.

FIGURE 13. Paralomis indica Alcock & Anderson, 1899. Morphological variability in outline of carapace lateral margins (dorsal view), male abdomen marginal armature (ventral view) and nature of branchial and cardiac regions (posterior view). A–C, male (IO/SS/ANO/00058; PCL 67.0 mm, CW 73.5 mm), southeast Arabian Sea, India; D–F, male (IO/SS/ANO/00120; PCL 79.7 mm, CW 84.9 mm), southeast Arabian Sea, India; G–I, male (IO/SS/ANO/00057; PCL 85.9 mm, CW 95.0 mm), southeast Arabian Sea, India; J–L, male (IO/SS/ANO/00054; PCL 77.3 mm, CW 83.4 mm), southwest Bay of Bengal, India. Scale bar = 10 mm.

FIGURE 14. Paralomis indica Alcock & Anderson, 1899. Morphological variability in outline of carapace lateral margins (dorsal view), male abdomen marginal armature (ventral view) and nature of branchial and cardiac regions (posterior view). A–C, male (IO/SS/ANO/00053; PCL 74.0 mm, CW 81.2 mm), southwest Bay of Bengal, India; D–F, male (IO/SS/ANO/00048; PCL 82.5 mm, CW 99.6 mm), northwest Bay of Bengal, India; G–I, male (IO/SS/ANO/00055; PCL 54.4 mm, CW 60.7 mm), northwest Bay of Bengal, India. J–L, juvenile male (IO/SS/ANO/00123; PCL 27.1 mm, CW 29.9 mm), northwest Bay of Bengal, India. Scale bar: 10 mm.

FIGURE 15. Paralomis indica Alcock & Anderson, 1899. Morphological variability in outline of carapace lateral margins (dorsal view), female abdomen marginal armature (ventral view) and nature of branchial and cardiac regions (posterior view). A–C, female (IO/SS/ANO/00060; PCL 70.1 mm, CW 70.0 mm), southeast Arabian Sea, India; D–F, female (IO/SS/ANO/00056; PCL 68.7 mm, CW 70.6 mm), southeast Arabian Sea, India; G–I, ovigerous female (IO/SS/ANO/00052; PCL 76.1 mm, CW 90.8 mm), southwest Bay of Bengal, India; J–L, ovigerous female (IO/SS/ANO/00050; PCL 64.2 mm, CW 74.0 mm), northwest Bay of Bengal, India. Scale bar: 10 mm.

FIGURE 16. Maximum Likelihood (ML) tree, showing relationships among Paralomis White, 1856; A, 12 species using COI gene sequence data, and, B, 10 species using 16S rRNA data. Numbers on branches represent bootstrap values expressed in percentage.

Tables

TABLE 1. Kimura 2 parameter (K2P) pair wise analysis based estimated intra genus genetic variation among COI sequences of species of Paralomis. MW118601_Paralomis_indica MW291128_Paralomis_ceres 0.137 HM020906_Paralomis_anamerae 0.113 0.071 HM020905_Paralomis_anamerae 0.113 0.069 0.002 EU493261_Paralomis_birsteini 0.115 0.068 0.032 0.030 HM020912_Paralomis_dofleini 0.131 0.129 0.105 0.107 0.112 HM020917_Paralomis_erinacea 0.115 0.077 0.037 0.035 0.051 0.096 HM020916_Paralomis_erinacea 0.115 0.077 0.037 0.035 0.051 0.096 0.000 HM020922_Paralomis_formosa 0.122 0.097 0.071 0.073 0.081 0.098 0.066 0.066 HM020921_Paralomis_formosa 0.122 0.097 0.071 0.073 0.081 0.098 0.066 0.066 0.000 HM020926_Paralomis_granulosa 0.110 0.125 0.108 0.106 0.134 0.124 0.104 0.104 0.106 0.106 EU493264_Paralomis_granulosa 0.110 0.125 0.108 0.106 0.134 0.124 0.104 0.104 0.106 0.106 0.000 KY426272_Paralomis_hirtella 0.125 0.092 0.075 0.075 0.088 0.101 0.051 0.051 0.088 0.088 0.117 0.117 AB428442_Paralomis_multispina 0.130 0.104 0.086 0.088 0.092 0.101 0.068 0.068 0.095 0.095 0.130 0.130 0.062 HM020927_Paralomis_spinosissima 0.120 0.095 0.068 0.066 0.079 0.092 0.031 0.031 0.090 0.090 0.102 0.102 0.047 0.060 HQ944664_Paralomis_zealandica 0.115 0.122 0.108 0.110 0.134 0.119 0.104 0.104 0.113 0.113 0.113 0.113 0.113 0.120 0.113

MW118601 _ Paralomis _ indica
MW291128 _ Paralomis _ ceres	0.137
HM020906 _ Paralomis _ anamerae	0.113	0.071
HM020905 _ Paralomis _ anamerae	0.113	0.069	0.002
EU493261 _ Paralomis _ birsteini	0.115	0.068	0.032	0.030
HM020912 _ Paralomis _ dofleini	0.131	0.129	0.105	0.107	0.112
HM020917 _ Paralomis _ erinacea	0.115	0.077	0.037	0.035	0.051	0.096
HM020916 _ Paralomis _ erinacea	0.115	0.077	0.037	0.035	0.051	0.096	0.000
HM020922 _ Paralomis _ formosa	0.122	0.097	0.071	0.073	0.081	0.098	0.066	0.066
HM020921 _ Paralomis _ formosa	0.122	0.097	0.071	0.073	0.081	0.098	0.066	0.066	0.000
HM020926 _ Paralomis _ granulosa	0.110	0.125	0.108	0.106	0.134	0.124	0.104	0.104	0.106	0.106
EU493264 _ Paralomis _ granulosa	0.110	0.125	0.108	0.106	0.134	0.124	0.104	0.104	0.106	0.106	0.000
KY426272 _ Paralomis _ hirtella	0.125	0.092	0.075	0.075	0.088	0.101	0.051	0.051	0.088	0.088	0.117	0.117
AB428442 _ Paralomis _ multispina	0.130	0.104	0.086	0.088	0.092	0.101	0.068	0.068	0.095	0.095	0.130	0.130	0.062
HM020927 _ Paralomis _ spinosissima	0.120	0.095	0.068	0.066	0.079	0.092	0.031	0.031	0.090	0.090	0.102	0.102	0.047	0.060
HQ944664 _ Paralomis _ zealandica	0.115	0.122	0.108	0.110	0.134	0.119	0.104	0.104	0.113	0.113	0.113	0.113	0.113	0.120	0.113

TABLE 2. Kimura 2 parameter (K2P) pair wise analysis based estimated intra genus genetic variation among 16S rRNA sequences of species of Paralomis. MW369444_Paralomis_indica MW362253_Paralomis_ceres 0.026 HM020957_Paralomis_aculeata 0.029 0.016 HM020960_Paralomis_anamerae 0.022 0.009 0.009 HM020959_Paralomis_anamerae 0.022 0.009 0.009 0.000 HM020962_Paralomis_dofleini 0.019 0.019 0.022 0.016 0.016 HM020971_Paralomis_formosa 0.022 0.009 0.013 0.006 0.006 0.016 HM020965_Paralomis_erinacea 0.026 0.019 0.016 0.016 0.016 0.019 0.016 HM020967_Paralomis_erinacea 0.026 0.019 0.016 0.016 0.016 0.019 0.016 0.000 KY426327_Paralomis_hirtella 0.022 0.016 0.019 0.013 0.013 0.016 0.013 0.009 0.009 HM020982_Paralomis_spinosissima 0.035 0.029 0.022 0.019 0.019 0.022 0.019 0.022 0.022 0.026 HM020981_Paralomis_zealandica 0.029 0.022 0.025 0.019 0.019 0.022 0.013 0.022 0.022 0.019 0.026 HM020980_Paralomis_zealandica 0.029 0.022 0.025 0.019 0.019 0.022 0.013 0.022 0.022 0.019 0.026 0.000

MW369444 _ Paralomis _ indica
MW362253 _ Paralomis _ ceres	0.026
HM020957 _ Paralomis _ aculeata	0.029	0.016
HM020960 _ Paralomis _ anamerae	0.022	0.009	0.009
HM020959 _ Paralomis _ anamerae	0.022	0.009	0.009	0.000
HM020962 _ Paralomis _ dofleini	0.019	0.019	0.022	0.016	0.016
HM020971 _ Paralomis _ formosa	0.022	0.009	0.013	0.006	0.006	0.016
HM020965 _ Paralomis _ erinacea	0.026	0.019	0.016	0.016	0.016	0.019	0.016
HM020967 _ Paralomis _ erinacea	0.026	0.019	0.016	0.016	0.016	0.019	0.016	0.000
KY426327 _ Paralomis _ hirtella	0.022	0.016	0.019	0.013	0.013	0.016	0.013	0.009	0.009
HM020982 _ Paralomis _ spinosissima	0.035	0.029	0.022	0.019	0.019	0.022	0.019	0.022	0.022	0.026
HM020981 _ Paralomis _ zealandica	0.029	0.022	0.025	0.019	0.019	0.022	0.013	0.022	0.022	0.019	0.026
HM020980 _ Paralomis _ zealandica	0.029	0.022	0.025	0.019	0.019	0.022	0.013	0.022	0.022	0.019	0.026	0.000