Lysmata amboinensis ( de Man, 1888 )

Jose, Sheena, Purushothaman, P., Madhavan, Manu, Akash, S., Bharathi, S., Karan, A. Dhina-, Kumar, T. T. Ajith & Lal, K. K., 2020, Two new records of hippolytoid shrimps, Lysmata hochi Baeza & Anker, 2008 (Decapoda: Lysmatidae) and Lysmata amboinensis (de Man, 1888) from Lakshadweep Islands, India with taxonomic notes, Zootaxa 4755 (2), pp. 353-364 : 357-361

Lysmata amboinensis ( de Man, 1888) ( Figs 4–5 )

Hippolysmata vittata var. amboinensis — de Man, 1888: 495.

Hippolysmata amboinensis — de Man, 1907: 426.

Hippolysmata (Hippolysmata) amboinensis — Holthuis (1947): 70, figs. 12–14; Zarenkov, 1971: 180.

Lysmata grabhami — Bruce (1974): 107, pl. 1, not Hippolysmata grabhami Gordon, 1935 .

Lysmata amboinensis — Hayashi (1975b): 286, figs. 1–4, pl. 5 [in part]; Debelius (1984): 112; Manning and Chace (1990): 112; Hayashi, 1994: 271–272, fig. 261a, d. f; Chace (1997): 74; Yang and Kim, 2006: 118–122, fig. 1–2; De Grave and Fransen (2011): 428; Prakash et al., 2016: 4, fig. 4.

Material examined. LYSLAMB/ NBFGR, 2 females (CL 9.0, 16.0 mm), 1 male (CL 8.0 mm) Arabian Sea, off Agatti Island, Lakshadweep, India, 10°49’13”N, 72°10’19”E, Temperature 280 C, Salinity 35 ppt, 2 m deep, September 2019.

Diagnosis: Rostrum ( Fig. 4a ) slender, moderately long and reaching distal end of the second antennular peduncle, 1.4 times as long as carapace; curving downwards basally but re-curved slightly in the tip of the rostrum; armed dorsally with 5 teeth and one epigastric. 1 st rostral tooth started the level of orbital margin, stiff setae present in middle of dorso-rostral carina for each tooth; ventral margin bearing 6 teeth with sharp tips. Carapace glabrous with a strong and elongated antennal spine, pterygostomine spine smaller and not elongated. Orbital margin is regularly concave with small-angle ventrally. Eyes are moderately large and just exceeding 2 nd dorso-rostral tooth. Stylocerite was stout, sharply pointed and not reaching the distal margin of the eye. Antennule peduncle reaching almost the level of distal end of scaphocerite, disto-dorsally few minute spines are present on each peduncle, lateral flagellum not having accessory branches. Basicerite is provided with a spine. Scaphocerite laterally convex, 4.1 times as long as wide with a lateral spine, antenna slender and long. Maxilliped III ( Fig 4b ) with exopod and extended beyond the scaphocerite; ultimate and anti-penultimate segments 1.8 and 2.3 times as long as penultimate segment respectively. First pereopods ( Fig 4c ) long, moderately slender with simple chela and extended beyond the scaphocerite by fingers; chela 1.2 times as long as carpus, palm 2.3 times as long as fingers; carpus about 1.2 and 1.4 times as long as palm and merus respectively. Pereopod II long and slender; ischium composed 3 articles, merus composed of 6 articles, carpus composed of 19 articles, and chela is simple with numerous long setae. Posterior three Pe- reopods are similar, long and slender, overreaching scaphocerite, dactylus biunguiculate and bearing 2 spines on posterior margin ( Fig 4d ). Pereopod III with propodus was bearing 11 spinules ventrally and few long setae in the distal margin, merus bearing 5 spines on distally. Pereopod IV with propodus contains 8 spinules ventrally; 4 spines on distally in merus. Pereopod V with propodus contains 6 spinules ventrally and 3 groups of long setae in distal region, merus bearing 2 distal spines. Abdomen pleura I–III rounded posteriorly without spine; pleura V generally terminated sharp tooth posteroventrally, the sixth somite 1.5 times as long as the fifth somite. Telson was 1.3 times as long as abdominal somite VI with 2 pairs of dorsolateral spines and 2 pairs of posterior spines (outer pair big and shorter than inner pairs).

Colouration of life: Carapace and abdomens ( Fig 5a & b ) pale orange with paired and longitudinal red bands on dorsally. Between these red bands, the middle portion with white stripe expanded like rectangular shape band laterally with strong white in the posterior end of the sixth abdominal somite and anterior portion of telson. Rostrum white, eyes are dark black, eyestalk covered with red band. Antennular peduncles with dark redden colour, which continues on outer flagellum dorsally up to few articles. Mouthparts with pale orange; penultimate and ultimate segments of 3 rd maxilliped are white. Other pereopods and peleopods are pale oranges. Telson of anterior 1/3 to posterior portion is white, uropods with red in colour and proximal and posterior-laterally with white bands.

Distribution: Red Sea, Mombasa, Gulf of Mannar, Gulf of Tonkin, Okinawa, Japan, Philippines and Indonesia to Hawaii and the Society Islands (Hayashi, 1975; Chace, 1997; Prakash et al., 2016). Presently, it is found that the distribution of the species is extended to Lakshadweep Islands.

Remarks: The present specimens Lysmata amboinensis agrees well with the description by Hayashi (1975) and Chace (1997) with following key characters: Length ratio of rostrum: Carapace, antennular peduncle: scaphocerite, 6 th: 5 th somite, 3rd maxilliped of anti-penultimate: Penultimate segments, first and second pereopods segments ( Table 1 ). However, minor discrepancies were noticed in the morphology of the present specimens. Rostrum formula 1+5/6, ratio of telson: 6 th abdominal somite (1.3 times) and 6 sub-segments in carpus of 2 nd pereopod. Hayashi (1975) reported from Myogajima Island, where the rostrum formula is 1-2+4-5/3-4, the ratio of telson: 6 th abdominal somite is 1.4 times and 8 sub-segments in Carpus of 2 nd pereopod.

L. amboinensis is characterized in having strong longitudinal red and white bands on the dorsal region of carapace and abdomen segments. Only two described species in the genus Lysmata have such colour pattern on dorsal regions: L. amboinensis ( de Man, 1888) and L. grabhami ( Gordon, 1935) which are widely distributed in Indian Ocean and east & west Atlantic waters (Hayashi, 1975; Chace, 1997; Baeza, 2010; Kassuga, Diele & Hostim-Silva, 2015; Prakash et al., 2016; Giraldes et al. 2018). L. amboinensis and L. grabhami are closely very similar and having a long rostrum (~0.8 times as longs as CL), a small orbital angle, presence of minute pterygostomine spine, long antennular peduncle with basal segment ~0.5 times as long as the CL and a 2 nd segment 2.0 times as long as the 3 rd segment, stylocerite very short, not nearly reaching middle of the basal segment, and the carpus of the 2 nd pereopod has 17–23 articles (Hayashi, 1975; Chace, 1997; Kassuga, Diele & Hostim-Silva, 2015; Prakash et al., 2016). However, the colouration of L. grabhami has a continuous middorsal white stripe started from the anterior tip of the rostrum to the posterior end of the telson (see Baeza, 2010, p. 263 and Kassuga, Diele & Hostim-Silva, 2015, fig 1). In contrast, the middorsal white stripe is interrupted in the posterior end of the 6 th abdominal somite and the anterior portion of the telson, and the uropodal exopod has one proximal and one distal white band, which was accepted as valid characters for this species in widely. But, still, no significant morphological difference between L. amboinensis and L. grabhami was available. Hayashi (1975) was differentiated the morphology of these two species from the material of Myogajima Island ( L. amboinensis ) and Funchal, Madeira ( L. grabhami ). Later Chace (1997) was noticed that those characters were not significant for this group. In the present examination, we segregated the difference in L. amboinensis as stylocerite is not reaching distal end of the eye (where reaching short distance beyond the eye for L. grabhami ), anti-penultimate segment of 3 rd maxilliped is more than 2.0 times as long as penultimate segment (while 1.8 for L. grabhami ), and palm of 1 st pereopod is 2.3 times as long as fingers (for L. grabhami is <2.0 times).

Two COI (Accession number: MT079209 & MT079210 ) sequences of L. amboinensis were generated and submitted to GenBank with sequence lengths of 603 base pairs. In genetic comparison, the present specimen sequences were compared with the available sequences of the genus Lysmata was obtained from the GenBank. The present Lakshadweep specimens formed a monophyletic clade with sequences of L. amboinensis (GenBank no: KC962192 , BOLD: AMINV030-08 & AMINV174-12) with genetic divergences of 0.0–0.8% ( Fig 3 ). The level of interspecies divergence of the present specimens L. amboinensis was compared with other sequences retrieved from NCBI and BOLD. Where, L. amboinensis and L. grabhami were showed the high genetic difference (11.0–12.0 %). Similarly, L. amboinensis and L. debelius (AMINV010-08, AMINV014-08, AMINV165-12 and AMINV16P8-12) were shown the high genetic difference in the ranges of 18.3–22.1%.

Figures

FIGURE 3. Phylogenetic tree for genus Lysmata using COI sequences with the Maximum Likelihood method.

FIGURE 4. Lysmata amboinensis (de Man, 1888) from Agatti Island, Lakshadweep, India. a. lateral close view of carapace, b third maxilliped; c, Pereopod, d, Chela of third pereopd.

FIGURE 5. Picture representation of Lysmata amboinensis (de Man, 1888) from Agatti Island, Lakshadweep, India; (A, lateral, B, dorsal view)

Tables

TABLE 1. Comparison of morphological characteristics of Lysmata amboinensis (de man, 1888) and Lysmata grabhami (Gordon, 1935) Aps=Anti-penultimate; Anp- antennular peduncle; CL=Carapace length; Prp=propodus; Ep-exopod; RL=Rostrum length; Sbs= Subsegment; TeL=Telson length.

S. No		amboinensis		grabhami
1	Author description	( Chace, 1997; Hayashi, 1975)	Present study	( Gordon, 1935; Kassuga et al., 2015)
2	Rostrum: Carapace	0.82 times	0.89 times	0.75 times
3	Rostral formula (dorsal/ventral)	1-2 + 4-5 3-4	1+5 6	(1+1)+4 4
4	CL	13 mm	9.0–16.0 mm	-
5	Antennal spine	Well developed	Well developed	Well developed
6	Pterygostomial spine	Small	Small	Small
7	Anp: scaphocerite	Equal or slightly beyond	Almost equal	Scarcely exceeding
8	Scaphocerite-length: width	4.5–5.5 times	4.1 times	-
9	Stylocerite		Short, not reaching	Reaching short distance
		Short	distal margin of eye	beyond the eye
10	Antennular flagellum (outer)	Without accessory branch	Without accessory branch	Without accessory branch
11	5 th somite posteroventral angle	-	Terminated sharp tooth	Pointed angle
12	6 th: 5 th somite length	1.5–1.7 times	1.5 times	-
13	TeL: 6 th somite a. Dorsal & terminal sp	1.4 times 2 & 2 pairs	1.3 times 2 & 2 pairs	-
14	3 rd maxilliped
	a. Ultimate: Penultimate b. Aps: Penultimate c. Ep reaching middle of Aps	1.4 times>2.0 times Not	1.8 times 2.3 times Not	1.4 times 1.8 times Yes
15	1 st Pereopod a. Palm: Fingers	2.3 times	2.3 times
	b. Carpus: palm c. Carpus: merus	1.2 times 1.3 times.	1.2 times 1.4 times	<2.0 times
16	2 nd Pereopod a. Carpus:Chela b. No of Sbs in Carpus c. No of Sbs in merus d. No of Sbs in ischium	7.0 times 19–20 8 3	7.05 times 19 6 3	- - 17–23 7 -
17	3 rd – 5 th Pereopods
	a. Ventral spines on Prp b. Prp: dactylus c. Merus: Prp	13—18 8.5 times 1.1–1.3 times	8–11 spinules 7.9–8.2 times 1.0–1.13 times	10–15
	d. Distal spines on merus	3–5	2–5	2–5
18	Type locality	Ambon, Indonesia		Funchal, Madeira
19	Depth	20 m	1 m	3–55 m