Kochimysis pillaii, Panampunnayil & Biju, 2007

Panampunnayil, S. U. & Biju, A., 2007, A new genus and species of Heteromysini (Crustacea- Mysidacea) from the backwater of Kochi (Kerala, India), Journal of Natural History 41 (29 - 32), pp. 1955-1963 : 1957-1962

publication ID

https://doi.org/ 10.1080/00222930701515553

persistent identifier

https://treatment.plazi.org/id/03DD9155-1562-7343-FE25-B4005327FED2

treatment provided by

Carolina

scientific name

Kochimysis pillaii
status

sp. nov.

Kochimysis pillaii sp. nov.

( Figures 2–5 View Figure 2 View Figure 3 View Figure 4 View Figure 5 )

Material

Holotype: IOBC-0507-10-50-2006, adult male, 3.5 mm. Allotype: IOBC-0507 A-10-50- 2006, female with embryos, 3.3 mm.

Other material. Two adult males, one adult female, two immature males, two immature females, and two juveniles.

Description

Body short and smooth. Anterior margin of carapace broadly triangular, rostrum inconspicuous, antero-lateral corners rounded, posterior margin emarginate leaving last three thoracic somites dorsally exposed ( Figure 2A View Figure 2 ). In female frontal border of carapace scarcely produced ( Figure 2B View Figure 2 ). Eyes well developed, closely set together, globular; eyestalks short and thick, cornea narrower than stalk. Antennular peduncle short and stout, first segment longer than distal segment, outer distal corner with finger-like lobe bearing two setae, second segment short with one stout plumose seta on inner distal corner; third segment with three setae on inner distal angle and one seta on inner margin, male lobe small, rounded and hirsute ( Figure 2C, D View Figure 2 ). Antennule of female as in male except for absence of male lobe ( Figure 2E View Figure 2 ).

Antennal scale oval, 3.5 times as long as broad, setose all round, shorter than antennular peduncle, distal suture absent; antennal peduncle longer than scale, three-segmented, second and third segments long and subequal in length; antennal sympod with finger-like process between peduncle and scale ( Figure 2F, G View Figure 2 ).

Labrum with rounded anterior margin, posterior border bilobed ( Figure 3C View Figure 3 ). Mandibles with well-developed lacinia mobilis, incisor, and molar processes; spine row of left with four strong spines and right with three spines ( Figure 3B View Figure 3 ); palp three-segmented, first segment short, second segment broad and elongate bearing two setae on outer distal corner, third segment half length of second with oblique distal margin armed with row of pectinate setae and one long terminal seta ( Figure 3A View Figure 3 ). Inner lobe of maxillule with three long and six short plumose setae, outer lobe distally armed with 10 spines and three subterminal setae ( Figure 3D View Figure 3 ). Maxilla with large basal lobe, distal lobe deeply bifid, second segment of endopod oval, segments subequal in length; exopod with three setae at apex ( Figure 3E View Figure 3 ).

First thoracic appendage with exopod and epipod; basis of endopod with prominent gnathobasic lobe, ischium and merus moderately produced inwards, all segments with setae on inner margin, dactylus with nail and group of pectinate setae ( Figure 3F View Figure 3 ). Second thoracic endopod with carpus and propodus with notched outer margin ( Figure 3G View Figure 3 ); in female carpus and propodus simple ( Figure 3H View Figure 3 ); basis produced inwards; dactylus with group of pectinate setae, nail absent. Third and fourth thoracic endopods ( Figure 4A, B View Figure 4 ) with carpopropodus divided into three subsegments; remaining endopods ( Figure 4C, D View Figure 4 ) becoming longer posteriorly, carpopropodus divided into four subsegments; dactylus ending in two small setae. Basal segment of exopod rounded, flagelliform part nine segmented. In male eighth thoracic limb with small tubular genital organ ( Figure 4D View Figure 4 ).

Pleopods in both sexes uniramous, reduced to unsegmented setose plates, becoming longer posteriorly ( Figure 5 View Figure 5 A–E).

Uropods broad, longer than telson ( Figure 5F View Figure 5 ), both rami oval, setose all round and without spines ( Figure 5G View Figure 5 ), exopod longer than endopod.

Telson entire, longer than last abdominal segment, slightly longer than broad at base, lateral margins nearly straight, distal third armed with six progressively longer spines, apex broadly rounded with two pairs of spines, outer pair almost three times as long as inner pair ( Figure 5H, I View Figure 5 ).

Etymology

This species is named after Dr N. Krishna Pillai in recognition of his valuable contributions to knowledge of Mysidacea of the Indian waters.

Remarks

This species resembles Deltamysis holmquistae, Bowman and Orsi, 1992 , the monotype of the genus, in the form and armature of the telson, and the morphological differences are as stated in the remarks of the genus. Other differences observed are: (1) in K. pillaii the cornea of the eye is narrower than the eyestalks, whereas in D. holmquistae the cornea is as wide as the stalk; (2) in K. pillaii the antennal peduncle is much longer than the antennal scale and the distal two segments of the peduncle are subequal in length. In D. holmquistae the antennal peduncle is only as long as the scale and the third segment is longer than the second segment; (3) in K. pillaii the spine row of the mandible consists of three to four spines as against eight in D. holmquistae ; (4) in K. pillaii the outer pair of apical spines of the telson are nearly three times as long as the inner pair, whereas in D. holmquistae the outer spines are only less than twice as long as the inner pair. The male of this species can be easily distinguished by the presence of notches on the second thoracic endopod.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Mysida

Family

Mysidae

Genus

Kochimysis

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