Allobathynella donggangensis, 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 : 128-134

Allobathynella donggangensis sp. nov. ( Figs. 68-72 )

Etymology

The species name is derived from the name of the riv- er (Donggang), where the material was collected.

Material examined Holotype (adult female), allotype (adult male), paratypes (one adult females and four adult males). Holotype dissected on eight slides ( NIBR IV0000267102 ) . Allotype dissected on eight slides ( NIBR IV0000267103 ). One female paratype and five male paratypes each as a whole specimen on separate slides ( NIBR IV0000267104- 0000267108 ) .

Type locality

South-Korea, Kangwon-Do (province), Jeongseon- Gun (county), Jeongseon-Eup (town), A gravel bank of small stream (Eochun) of Donggang (37°22′20.9″N, 128°40′48.4″E), 24. May 2014 (J.-L. Cho and J.-G. Park)

Description

Size (mm). Body length: Ş 2.54 (other female: 2.50), ♂: 2.50 mm; other males: 2.30-2.50 mm), approximately 10 times as long as wide. Head slightly shorter than anterior four thoracic segments combined. Male differs from female in protopod of thoracopod VI and thoracopod VIII.

Antennule ( Fig. 68A ) 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 one ventrolateral seta, and with 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 three 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. 68B ) 7-segmented, as long as the length of antennular segments 1-5. Setal formula: 0 + 0/0 + 0/1 + 0/1 + 1/0 + 0/0 + 1 + 1/4(1).

Labrum ( Fig. 68C ) flat, with nine main teeth flanked by four teeth on both lateral sides. Ventral surface concave, with one round median projection bearing two spinules and three pair of teats and with numerous combs of ctenidia on concave surface medially covered by tiny grain-like protrusions.

Mandible ( Fig. 68D ) with incisor process of four teeth. Tooth of ventral edge absent. Spine row consisting of nine spines. Palp of one segment with one long terminal seta.

Maxillule ( Fig. 68E ) 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 outer distal margin. Terminal spine 1.3 times as long as other ones.

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epipod C exopod B A endopod A-C endopod exopod epipod D D F F E E

Maxilla ( Fig. 69A ) four-segmented, setal formula 3-5- 9-6.

Thoracopods I-VII ( Figs. 69 B-F, 70A-C). Thoracopod I-IV increasing in size posteriorly. Thoracopods IV-VII similar in size. Thoracopods IV-VII (or V-VII in left) each bearing one epipod on the protopod. Basipod with one distal seta in thoracopods I-V, with each one distal and median seta in thoracopods VI-VII. Number of segments of the exopod of the thoracopods I-VII: 3-4- 5-6-6-6-6. Exopodal segments with each one dorsal and ventral seta, except basal segment lacking dorsal seta in thoracopods II-VII and second segment lacking dorsal

February 2016 PARK AND CHO-FOURTEEN SPECIES OF ALLOBATHYNELLA 133

B A A, B C C

seta in thoracopod V-VII. 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 2 + 1/3 + 2/1 + 1/4(2)

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

Thoracopods III-VI 1 + 1/1 + 2/0 + 1/4(2)

Thoracopods VII 1 + 1/1 + 2/0 + 1/3(1)

Thoracopod VIII of male ( Fig. 71 A-D) perpendicular to body, in form of a bell in lateral view, 1.3 times longer than wide. Protopod with a prominent penial region bearing a distal opening. Inner margin of penial region (dental lobe) with 15 teeth. Epipod flat, with round distal part not reaching lower margin of exopod. Basipod with one small seta near base of endopod, inner margin with spinules, distally drawn out into round projection. Exopod one third of size of basipod, round, with two distal lobes. Upper lobe with four spinules, lower lobe with five dentils. Endopod small, round, with two distal setae of different size. Outer seta three times longer than inner one. Thoracopod VIII of female ( Fig. 71E) conical in ventral view, with two or three spine-like distal projections.

First pleopod ( Fig. 71F) in form of stub bearing two distal setae.

Uropod ( Fig. 72A, C) bearing ten spines on inner margin of sympod of similar size. Endopod 53% as long as sympod, with two dorsal 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 four additional spines along inner margin. The terminal spine longer than subterminal one. Most distal spine of inner margin smaller than subterminal one, one third as large as terminal one. Three proximal spines of inner margin small, half as large as distal one. Exopod shorter than endopod (45% of sympod), with six setae inclusive of one basi-ventral seta.

Pleotelson ( Fig. 72B, C) without seta. Anal operculum nearly flat.

Furcal rami ( Fig. 72B, C) 1.3 times as long as wide, with two large distal spines, and four (left) or five (right) successively smaller spines on inner margin, and with two dorsal setae.

Figures

Fig. 68. Allobathynella donggangensis (holotype: Ş): (A) Antennule (dorsal); (B) Antenna (dorsal); (C) Labrum (ventral); (D) Mandible (ventral); (E) Maxillule (ventral). Scale bars=0.1 mm.

Fig. 69. Allobathynella donggangensis (holotype: Ş): (A) Maxilla (dorsal); (B) Thoracopod I (frontal); (C) Thoracopod II (frontal); (D) Thoracopod III(frontal); (E) Thoracopod IV(frontal); (F) Protopod of thoracopod IV(frontal). Scale bars=0.1 mm.

Fig. 70. Allobathynella donggangensis (holotype: Ş): (A) Thoracopod V (frontal); (B) Thoracopod VI (frontal); (C) Thoracopod VII (frontal). Scale bar=0.1 mm.