Nipponbathynella shigaensis Park & Cho 2015, sp. nov.
Creators: name: Park, Jong-Geun
name: Cho, Joo-Lae
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Bathynellacea
Parabathynellidae
Nipponbathynella
Nipponbathynella shigaensis

description: Nipponbathynella shigaensis sp. nov.
(Figures 15–19)
Etymology
The species name is derived from the province, Shiga-Ken (Ken means prefecture), where the species was collected.
Material examined
Type material
Holotype. Male, dissected on seven slides. Japan, Shiga-Ken (prefecture), Takashima- Shi (city), Imazu-Cho (commune), Hamabun, Imazu Beach, Groundwater 35–02, 4 October 2011 (M.J. Grygier and M. Matsuda) (LBM1430005567).
Allotype. Female, dissected on six slides, same data as of holotype (LBM1430005568).
Paratypes. One female and one juvenile each kept as a whole specimen in a slide, same data as holotype (LBM1430005569, LBM1430005570).
Description of adult male (holotype)
Body (Figure 15A). Elongated and cylindrical, length 1.50 mm, approximately 10 times as long as wide. Head as long as wide, shorter than anterior three thoracic segments combined.
Antennule (Figure 15B) six-segmented. First segment with one seta on inner distal margin, with two simple dorsal setae and each one plumose seta dorso-laterally, laterally and ventro-laterally. Second segment with one group of four plumose setae, with one simple seta on inner distal margin and inner laterally with one ventral seta. Third segment with two lateral setae, one seta on inner distal margin and inner laterally with one ventral seta. Inner flagellum of third segment with three simple setae. Fourth segment with one stub seta and one plumose seta on dorsal margin, and with two stub setae and two plumose setae on outer distal apophysis being slightly protruded. Fifth segment with a medial group of two inner setae, one dorsal aesthetasc and one dorsal simple seta, and distally with three setae, two dorsal aesthetascs, one dorsal seta and one lateral aesthetasc. Sixth segment as large as one half of the fifth segment, with three subterminal aesthetascs and four simple setae.
Antenna (Figure 15C) two-segmented, as long as the length of the first antennular segment. Proximal segment without setae, distal segment with two simple terminal setae and one plumose seta.
Labrum (Figure 15D) flat, with 11 median teeth of more or less similar size flanked by three lateral teeth, lateral-most teeth with tiny terminal spinule. Inner surface concave, with two pairs of nipple-like lateral protrusions and with ctenidia and tiny projection in middle region.
Mandible (Figure 15E) with incisor process of three teeth. Tooth of ventral edge triangular. Spine row consisting of four spines. Palp of one segment, with one apical seta not exceeding incisor process in length.
Maxillule (Figure 15F) two-segmented. Proximal segment with four setae on inner distal margin and with two medial rows of ctenidia. Distal segment with two terminal spines, with four spines and one small spine on inner edge, and with three simple setae on outer distal margin.
Maxilla (Figure 15G) four-segmented, setal formula 2-4-9-7.
Thoracopods I–VII (Figures 16A–D, 17A–D) increasing in size up to thoracopod IV, thoracopods IV–VII similar in size. Thoracopods II–VII each bearing one epipod on protopod. Basis of thoracopods I–VII with one seta each. Basis of thoracopods II–VII with long and strong hairs along outer margin. Exopod of thoracopod I one-segmented with one medial seta on ventral margin. Exopod of thoracopods II– VII two-segmented. Endopods of thoracopods I–VII four-segmented, setal formulae:
Thoracopod I 1 + 0/1 + 1/0 + 1/3(1)
Thoracopods II–VII 0 + 0/1 + 1/0 + 1/2(0).
Thoracopod VIII (Figure 18A, B) bell-shaped and tilting backwards in lateral view, 1.2 times longer than wide. Protopod massive, with penial region of two smooth lobes, inner lobe absent. Epipod narrow and elongated, distal end barely reaching penial region. Basis nearly trapezoid, without distal spur, with one seta. Exopod half as long as basis, longer than wide, one-lobed and smooth. Endopod longer than wide, with two distal setae of different sizes.
First pleopod absent (Figure 15A).
Uropod (Figure 19B, C) with load-shaped sympod bearing 13 spines on inner margin. Proximal-most spine smaller than remaining ones decreasing slightly in size distally. Distal-most spine thicker and longer than others. Endopod 24% as long as sympod length, drawn into spur, with two setae on the outer basis of spur. Exopod longer than endopod, 46% as long as sympod, with one outer seta, two terminal setae and one inner seta. Inner seta nearly subterminal, strong, thicker and slightly shorter than inner terminal seta. Outer terminal seta nearly subterminal. All setae and spines on uropod barbed.
Pleotelson (Figure 19C, D) without seta.
Anal operculum protruded.
Furcal rami (Figure 19C, D) approximately 1.2 times longer than wide, with two distal spines and six (right) or seven (left) additional spines on inner margin, and dorsally with one plumose seta and one simple seta and ventrally with furcal organ.
Description of adult female (allotype)
The female differs from the male in the inner margin of the protopod of the thoracopod VI and in the form of the thoracopod VIII. Body length 1.55 mm (other females: 1.50 mm). Inner margin of the protopod of the thoracopod VI (Figure 17C) undulated and with opening of oviduct. Thoracopod VIII (Figure 19A) in form of two radicles bearing one tiny spine distally
description: Published as part of Park, Jong-Geun & Cho, Joo-Lae, 2015, Redefinition of Nipponbathynella based on the four new species from East Asia (Crustacea: Bathynellacea: Parabathynellidae), pp. 2275-2307 in Journal of Natural History 49 (37) on pages 2295-2301, DOI: 10.1080/00222933.2015.1023226, http://zenodo.org/record/4000033