Plesionika alcocki
Creators: name: Chakraborty, Rekha Devi
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Pandalidae
Plesionika
Plesionika alcocki
Plesionika narval

description: 4.1 Plesionika alcocki (Anderson, 1896) – Fig 1    
 Pandalus alcocki — Anderson, 1896:92 [type-locality: Laccadive Sea off Malabar Coast of India; 9°34'57"N 75°36'30"E; 743 meters].   
 Pandalus (Plesionika) alcocki — Alcock and McArdle, 1901, pi. 52: figs. 2, 4.   
 Plesionika alcocki: De Man, 1920: 105; Balss, 1925: 278, fig. 48; Mohamed and Suseelan, 1973; Chace, 1985: 55; Hayashi, 1986: 127, 270, fig. 81; Kensley, Tranter & Griffin, 1987: 313; Dave, 2002: 347; Fransen, 2006: 62-65, fig.17.   
 Material examined: India, Tamil Nadu, Tuticorin fishing port, fishing off Bay of Bengal, 8°47′40"N, 78°09'37"E, 200- 300 m, Jan 2015, 3 males CL 22-25 mm, (CMFRI).   
  4.2 Plesionika narval (Fabricius, 1787) – Fig 2 (a-k)    
 Astacus narval Fabricius, 1787: 331 (type locality: probably Nice, Mediterranean).   
 Description: Rostrum armed dorsally with 4-6 teeth, ventrally armed with 8-23 teeth becoming obscure anteriorly; orbital margin rather regularly concave; abdomen without posteromesial tooth or median dorsal carinae on 3 rd somite, 4 th somite pleuron rounded, without marginal denticle, 5 th somite pleuron rather sharply acute posteroventrally; telson with 4 pairs of dorsolateral spinules, including a pair adjacent to lateral pair of posterior spines; stylocerite rather narrowly acute; antennal scale long as wide, distolateral tooth not reaching level of distal margin of blade; third maxilliped with epipod; pereiopods with epipods on 4 anterior pairs, 3 rd pair overreaching antennal scale by lengths of dactylus, propodus, and 1/3 of carpus, dactyl about ¼ as long as propodus, none of the pereiopods extremely slender or thread like.   
 Parapandalus serratifrons: De Man, 1920: 146, Pl. 12, fig. 34a, c, Pl. 13, fig. 34, 34b, d, e (non Borradaile, 1900).   
 Parapandalus spinipes: Kubo, 1965: 611, fig. 958 (non Bate, 1888).   
 Parapandalus narval: Crosnier and Forest, 1973: 221, fig. 69a; Crosnier, 1976: 235, fig. 4b.   
 Plesionika serratifrons: Chace, 1985: 121, figs. 55, 56; Hayashi, 1986: 139, 274, fig. 89 (non Borradaile, 1899).   
 Plesionika narval: Lemaitre and Gore, 1988: 385, figs. 3k-m, 4; Chan and Crosnier, 1991: 443, figs. 12a-c, 13a, 14a-c, 15ae, 34-36; Miyake, 1998: 61, Pl. 21, fig. 1; Li and Komai, 2003: 265; Li, 2006a: 370; Li and Davie, 2006: 161.   
 Material examined: India, Kerala, Kalamukku fishing port, City of Kerala, fishing off 9°59’02.91”N 76°14’33.14”E, 250- 300 m, 4 th April 2014, 14 males CL 10-15 mm, 7 ovigerous females CL 13-14 mm, 5 non ovigerous females CL 13-15. Voucher specimen (ED.2.4.3.4) was deposited in Marine Biodiversity Referral Museum of Central Marine Fisheries Research Institute, Cochin, India.   
 Coloration: Deep red to pale orange   
 Distribution: Western Indian Ocean: East Africa, Gulf of Aden, Maldives, Bay of Bengal (BOB) and Andaman Sea, Indonesia, Japan and Philippines; at depths between 287 and 1170 m [8, 20, 17, 2]. The present specimens were obtained from the southeast coast, off the BOB, depths of 200-300 m from India.   
 Description: Body size is usually small. The morphological analysis of the specimens was performed using conventional methods, revealed the absence of denticle on the 4 th abdominal pleura; rostrum is 1.7-1.8 times as long as carapace and the dorsal margin armed with 48-61 teeth over the entire length, including 5-6 teeth on carapace posterior to the level of orbital margin, ventral margin armed with 33-38 teeth, posterior 10 ventral teeth corresponding to 15 dorsal teeth. Eye diameter 0.1-0.3 times of carapace, cornea broader than the eyestalk, antennular peduncle with stylocerite acute barely overreaching 1 st antennular segment, antennal scale 4.7-5.3 times as long as wide with distolateral tooth overreaching rounded blade. Antennal spine stronger while pterygostomian spine was found to be weak. Abdomen with 3 rd somite rounded posteriorly unarmed, without median dorsal carinae, pleura of 3 rd and 4 th somite rounded while that of 5 th is acute. Sixth abdominal somite is 2.2-2.6 times as long as maximum height. Telson is 1.1 times as long as 6 th abdominal somite and armed with 3 pairs of dorsolateral spinules and two pairs of longer lateral spines were found at its posterior end. Maxilliped III with well-developed epipod, overreaching antennal scale and its penultimate segment (9 mm) is almost 1.8 times than terminal segment (5 mm), terminal and penultimate segments combined 1.1-1.3 times as long as carapace (12 mm) and the ultimate segment is equal to carapace length. Pereiopods without epipods extremely slender and thread like.   
 Remarks: The present specimen shows similarity with the identification key proposed to this species [8, 17], particularly with the following diagnostic characters: Rostrum armed dorsally with 4-6 teeth, ventrally armed with 8-23 teeth becoming obscure anteriorly; abdomen without posteromesial tooth or median dorsal carinae on 3 rd somite, 4 th somite pleuron rounded, without marginal denticle, 5 th somite pleuron rather sharply acute posteroventrally; telson with 4 pairs of dorsolateral spinules. In the present study, three male specimens were obtained at a depth of 200-300 m, while in the earlier records from Indian water it has been reported at higher depths of 496-1093 m.   
 Genetic distance: COI (accession number: KX530799, KX530800) and 16S (accession number: KX364188) sequences of P. alcocki were submitted to GenBank. The sequence lengths are 618 and 464 bp for cytochrome c oxidase I (COI) and 16s rDNA genes, respectively. The intraspecies genetic divergence between the present specimen and other sequences retrieved from NCBI was recorded for COI (KP759494 & JX681738: 23% & 24%) and 16S (KX364188 & KX364189: 10% & 11%).   
 Coloration: Body and appendages generally reddish, body with 1 subdorsal and 2 lateral red coloured longitudinal stripe extending along almost entire body length from anterior carapace to posterior abdomen on both sides, subdorsal stripe running from upper orbital margin and fading on abdominal somite IV and V, 1 lateral stripe running from antennal spine to tailfin another running from pterygostomian spine to uropod, slightly faded than subdorsal stripe, rostrum red, margins and teeth white; antennular flagellum white, basal portion of antennal flagellum, anterior appendages and basal parts of posterior appendages light red to white; pereiopods red distally and pink proximally, uropods translucent with orange-red margins; eggs pale blue.   
 Distribution: Indo-West Pacific from Madagascar to French Polynesia, Japan, Korea, Mediterranean, East Atlantic from Gibraltar to Cape Verde Islands, South Atlantic, Red Sea, and northward to Japan, at depths of 35- 400 m. Appeared in stray numbers among the deepsea shrimp landed in Kerala, India.   
 Remarks: Plesionika narval is recorded for the first time from India (off the Arabian coast). Overall 26 specimens were segregated from the deepsea shrimp discards which include 14 male and 12 female were obtained. Total length, carapace length, rostral length, weight in male and female ranged from 54-73 mm, 10-15 mm, 15-24 mm, 0.6-1.2 g and 65-78 mm, 13-18 mm, 17-25 mm, 0.8-1.5 g, respectively. Of the total 12 female specimens recorded 5 were non-berried and the rest were ovigerous. The fecundity in P. narval ranged from 162 to 698 (TL: 70-78 mm, CL: 13-14 mm and weight: 1.1-1.5 g) with an average width of the egg was found to be 0.2 mm. The eggs were spherical in shape with bluish green colour in the freshly acquired berry. The present specimens agree well with the diagnosis [19].   
 Genetic distance: COI (accession number: KP398863, KP398864) and 16S (accession number: KM057378, KM047390, KM047389, KP398866) sequences of P. narval were submitted to GenBank. The intraspecies genetic divergence between the present specimen and other sequences retrieved from NCBI varied for COI (KJ670310, JQ305934, JN412729, JQ305933: 15% - 16%) and 16S (KJ670313, JN412691 & MK470812: 8% - 16%) while the intraspecies genetic distance for the Indian P. narval was negligible the COI (0%) and 8 – 13% in 16S.
description: Published as part of Chakraborty, Rekha Devi, 2021, Notes on Plesionika alcocki (Anderson, 1896) and Plesionika narval (Fabricius, 1787) from the southern coast of India, pp. 281-287 in International Journal of Fisheries and Aquatic Studies 9 (1) on pages 282-283, DOI: 10.22271/fish.2021.v9.i1d.2412, http://zenodo.org/record/12550451