Allobathynella gangneungensis, Park & Cho, 2016

Park, Jong-Geun & Cho, Joo-Lae, 2016, Fourteen new species of Allobathynella Morimoto and Miura, 1957 from South Korea: with a redescription of A. coreana Morimoto, 1970 (Crustacea, Bathynellacea, Parabathynellidae), Journal of Species Research 5 (1), pp. 49-156 : 134-139

Allobathynella gangneungensis sp. nov. ( Figs. 73-76)

Etymology

The species name is derived from the name of the city (Gangneung-Si), where the material was collected.

Material examined

Holotype (adult female), paratypes (five adult females and two juveniles). Holotype dissected on seven slides ( NIBR IV0000267077 ). One female paratype dissected on seven slides ( NIBR IV0000267078 ), three females each as a whole specimen in separate slides ( NIBR IV0000267079-267081 ), two juveniles together as a whole specimen in a slide ( NIBR IV0000267082 ) .

Type locality

South Korea, Kangwon-Do, Gangneung-Si, Gangdong-Myeon , Imgok-Ri (37°39′44.9″N, 128°58′06.3″E), 07 October 2011, leg. J.-G. Park.

Description

Size (mm). Body length: 1.28 (other females: 1.05- 1.25), approximately 10 times as long as wide. Head as long as anterior three thoracic segments combined ( Fig. 73A).

Antennule ( Fig. 73B) 7-segmented. First segment with one seta on inner distal margin, with two simple dorsal setae and with four plumose setae. Position of each plumose setae: dorsally, dorso-laterally, laterally and ventro-laterally. Second segment with one group of four plumose setae and with one simple seta dorsally and two simple setae ventrally on inner distal margin. Third segment with two lateral setae including one plumose seta, with one ventrolateral seta, and one dorsal seta and two ventral setae on inner distal margin. Inner flagellum of third segment with three simple setae. Fourth segment with one stub setae and one plumose seta on dorsal margin, and with two stub setae and two plumose setae on outer distal apophysis. Fifth segment distally with two simple setae and one small plumose seta, two dorsal aesthetascs and one simple seta. Sixth segment with four setae including one plumose seta on inner margin, and with two aesthetascs and one simple seta and one aesthetasc dorsally. Seventh segment with three subterminal aesthetascs and four simple setae.

Antenna ( Fig. 73C) 7-segmented, as long as the length of antennular segments 1-5. Setal formula: 0 + 0/0 + 0/1 + 0/1 + 1/0 + 0/1 + 1 + 1/5(1).

Labrum ( Fig. 73D) flat, with six main teeth flanked by one tooth on both lateral sides. Ventral surface concave, with one round median projection bearing two spinules and two pairs of teats and with numerous combs of ctenidia on concave surface.

Mandible ( Fig. 73E) with incisor process of three teeth. Tooth of ventral edge absent. Spine row consisting of six spines. Palp of one segment, with one terminal seta.

Maxillule ( Fig. 74A ) two-segmented. Proximal segment with four setae on inner distal margin. Distal segment with two terminal smooth spines, with four smooth spines on inner edge, and with three simple setae on out- er distal margin. Terminal spine nearly two times as long as other ones.

Maxilla ( Fig. 74B ) four-segmented, setal formula 3-4-

February 2016 PARK AND CHO-FOURTEEN SPECIES OF ALLOBATHYNELLA 135

A A 0.5 mm D, E B B, C C D E

8-6.

Thoracopods I-VII ( Figs. 74 A-C, 75A-C, 76A). Thoracopod I-IV increasing in size posteriorly. Thoracopods IV-VII similar in size. Thoracopods III-VII each bearing one epipod on the protopod. Basipod with two distal setae in thoracopod I, with one distal seta in thoracopods II-VI, with each one distal and median seta in thoracopod VII. Number of segments of the exopod of the thoracopods I-VII: 2-3-3-3-4-3-3. Exopodal segments with each one dorsal and ventral seta, except basal segment lacking dorsal seta in thoracopods II-VII and except second segment lacking dorsal seta in thoracopod V. Tiny process present between two setae of distal segment. Dorsal seta on distal segment of exopod barbed with strong hairs. Endopod of the thoracopods I-VII four-segmented, setal formulae:

Thoracopod I 1 + 1/2 + 1/1 + 1/4(2)

Thoracopods II-IV 1 + 1/1 + 1/0 + 1/4(2)

Thoracopods V-VII 0 + 1/0 + 1/0 + 1/4(2)

Thoracopod VIII of female ( Fig. 76B, C ) conical in ventral view, with two spine-like distal projections. Thoracopod VIII of male unknown.

First pleopod ( Fig. 76B, C ) in form of stub bearing two distal setae.

Uropod ( Fig. 76D ) bearing seven spines on inner margin of sympod, two most distal spine slightly larger than other ones of similar size, most proximal spine significantly smaller than other ones. Endopod 53% as long as sympod, dorsally with one tiny spine and one plumose setae near the base, with two terminal setae and one subterminal plumose seta on outer margin and with one terminal spine, one subterminal spine and two additional spines on inner margin. The terminal spine longer than subterminal one. Distal spine of inner-margin smaller than subterminal one, 1/3 as large as terminal one. Proximal spine of inner-margin small, one third as large as distal one. Exopod shorter than endopod (44% of sympod), with four setae inclusive of one basi-ventral seta.

Pleotelson ( Fig. 76E ) without seta. Anal operculum protruded with round tip.

Furcal rami ( Fig. 76E ) 1.3 times as long as wide, with two large distal spines and two successively smaller spines on inner margin, and dorsally with two plumose setae.

Figures

Fig. 74. Allobathynella gangneungensis (holotype: Ş): (A) maxillule (ventral); (B) maxilla (dorsal); (C) Thoracopod I (frontal); (D) Thoracopod II (frontal); (E) Thoracopod III (frontal). Scale bars=0.05mm.

Fig. 76. Allobathynella gangneungensis (holotype: Ş): (A) Thoracopod VII (frontal); (B) Thoracopod VIII (ventral); (C) 8th thoracomere and 1st pleomere (ventral); (D) Uropod (dorsal); (E) Pleotelson and furcal rami(dorsal). Scale bars=0.05 mm.