Allobathynella yeongjuensis, 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 : 96-101

Allobathynella yeongjuensis sp. nov. ( Figs. 41-45 )

Etymology

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

Material examined

Holotype (adult male), allotype (adult female), paratype (one adult male and two adulte females). Holotype dissected on six slides ( NIBR IV0000140016 ) . Allotype dissected on six slides ( NIBR IV0000140017 ) . Paratypes each kept as a whole specimen in separate slides ( NIBR IV0000140018-000140020 ) .

Type locality

South-Korea, Kyungsangbuk-Do, Yeongju-Si Munjeong-Myeon (37°27′09.5″N, 127°31′01.5″E), 23. October 2009, leg. J.-L. Cho.

Description

Size (mm). Body length of holotype: 1.86; other male: 1.79. Body length of allothye: 1.73; other females: 1.67, 1.56; approximately 14 times as long as wide. Head as long as anterior three thoracic segments combined ( Fig. 41A ). Female differs from male in protopod of thoracopod VI and thoracopod VIII.

Antennule ( Fig. 41A ) 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 each two simple setae dorsally and ventrally on inner distal margin. Third segment with two lateral setae including one plumose seta, with two ventrolateral setae, 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. 41C ) 7-segmented, as long as length of antennular segments 1-5. Setal formula: 0+ 0/0 + 0/1 + 0/1 + 0/0 + 0/1 + 1 + 1/4(1).

Labrum ( Fig. 42A) flat, with eight main teeth flanked by three teeth on both lateral sides. Ventral surface concave, with one round median projection without spinules, numerous combs of ctenidia and two pairs of teats.

Mandible ( Fig. 42A) with incisor process of four teeth. Tooth of ventral edge absent. Spine row consisting of seven spines. Palp of one segment, 2.5 times as long as wide, with one terminal seta.

Maxillule ( Fig. 42B) two-segmented. Proximal segment with four setae on inner distal margin. Distal segment with two terminal smooth spines and four dentate spines on inner edge, and with three simple setae on outer distal margin. Terminal spine 1.2 times as long as other ones.

Maxilla ( Fig. 42C) four-segmented, setal formula 3-5- 10-6.

Thoracopods I-VII ( Figs. 42D, E, 43 A-C, 44A-C). Thoracopod I-IV increasing in size posteriorly. Thoracopods IV-VII similar in size. Thoracopods III-VII each bearing one epipod on protopod. Basipod with two distal setae in thoracopod I, with one distal seta in thoracopods II-VI, and with each one distal and median seta in thoracopod VII. Number of segments of exopod of thoracopods I-VII: 3-4-5-5-4-4-4. Exopodal segments with each one dorsal and ventral seta. Tiny process present between two setae of distal segment. Dorsal seta on distal segment of exopod barbed with strong hairs. Endopod of thoracopods I-VII four-segmented, setal formulae:

Thoracopod I 2 + 1/3 + 2/2 + 1/4(2)

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

Thoracopod V 1 + 1/2 + 2/0 + 1/4(2)

Thoracopod VI 1 + 1/1 + 2/0 + 1/4(2)

Thoracopod VII 0 + 1/1 + 2/0 + 1/4(2)

Thoracopod VIII of male ( Fig. 44 D-F) perpendicular to body, in form of a bell in lateral view, 1.2 times lon-

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ger than wide. Protopod with a prominent penial region bearing a distal opening. Inner margin of penial region with seven teeth. Epipod flat, with round distal part not reaching lower margin of exopod. Basipod without setae near base of endopod, distally drawn out into round projection. Exopod one third of size of basipod, round, with two distal lobes. Upper lobe smooth, lower lobe distally serrated. Endopod small, round, with two distal setae of different size. Outer seta two times longer than inner one. Thoracopod VIII of female ( Fig. 45A) tiny, round in ventral view, with two spine-like projections.

First pleopod ( Fig. 45A) in form of stub bearing one plumose seta and one tiny seta.

Uropod ( Figs. 45B, C) bearing ten spines on inner margin of sympod. Most distal spines longer and thicker than others. Endopod 50% as long as sympod, with two dorsal plumose setae near base, with two terminal setae and one subterminal plumose setae on outer margin and

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with one terminal spine, one subterminal spine and three additional spines on inner margin. Terminal spine slightly thicker and stronger than subterminal one. Most distal spine of inner margin 50% as large as terminal spine and two times as large as proximal ones. Exopod shorter than endopod (34% of sympod), with five setae inclusive of one basi-ventral seta.

Pleotelson ( Fig. 45B, C) without seta. Anal operculum nearly flat.

Furcal rami ( Fig. 45 C-E) 1.5 times as long as wide, with two large distal spines, and three smaller spines on inner margin, and with two dorsal plumose setae.

Figures

Fig. 41. Allobathynella yeongjuensis (holotype: ♂; allotype: Ş): (A) General habitus (lateral); (B) Antennule (dorsal); (C) Antenna (dorsal). Scale bars=0.05mm, unless specified.

Fig. 43. Allobathynella yeongjuensis (holotype: ♂): (A) Thoracopod III (frontal); (B) Thoracopod IV (frontal); (C) Thoracopod V (frontal). Scale bar=0.05mm.

Fig. 44. Allobathynella yeongjuensis (holotype: ♂; allotype: Ş): (A) Thoracopod VI ♂(frontal); (B) Protopod of thoracopod VI Ş(frontal); (C) Thoracopod VII ♂ (frontal); (D) Thoracopod VIII ♂ (lateral); (E) Thoracopod VIII ♂ (ventral); (F) Exopod of thoracopod VIII ♂. Scale bars=0.05mm.