taxonID	type	description	language	source
46D086CE5BE05E48AC9C004AB8765B3D.taxon	description	Description. Male. Trunk fully segmented, tapering posteriorly, finely granulated, without dorsal tubercles (Figs 2, 3). Cephalic segment with pair of projections at anterodorsal margin, pair of low tubercles present at middle of neck, cylindrical lateral extension bearing small ectal tubercle (Figs 2 A, 3 A, B). Lateral processes shorter than diameter, separated by half of diameter; small dorsal seta present on center of first lateral process and on dorsodistal margin of other lateral processes (Fig. 2 A, B). First lateral processes with two posterior tubercles; upper tubercle small, present at proximal; lower one large, present at distal. Second lateral processes having smaller anterior tubercle and two similar posterior tubercles. Third lateral processes bearing anterior tubercle and smaller posterior tubercle. Fourth lateral processes with small anterior tubercle. Ocular tubercle absent. Proboscis spindle-shaped, having low dorsal protuberance at 2 / 3 from base, with three pairs of dorsolateral swellings, bearing pair of furrows on ventral surface (Figs 2 A, B, 3 A, 4 C); mouth triradiate. Abdomen cylindrical, tapering distally, directing horizontally, with nodulous dorsal surface, not reaching distal margin of second coxa (Fig. 2 A, B). Chelifores absent. Palps five-articled, granular (Fig. 2 C). First article very short. Second article cylindrical, longest, five times as long as diameter, with seta on dorsomedian and dorsodistal margin. Third article cylindrical, 1.5 times length of diameter, without seta. Fourth article distally widened, 3.7 times length of proximal diameter, bearing large dorsal tubercle at 2 / 3 from base, with setae on dorsal, ventral and distal surface; dorsal tubercle 1.5 times as high as proximal diameter of fourth article, armed with three setae. Fifth article bulged proximally on inner side and dorsally, armed with many setae. Ovigers 10 - articled, granular (Fig. 2 D). First article short, attached to pectoralis major-like basement (Fig. 4 C). Second article cylindrical. Third article swollen at inner surface. Fourth article tapering at proximal, longest, with setae on outer and distal surface. Fifth article curved, with short setae on outer surface. Sixth article cylindrical, second-longest, with short setae on outer-distal surface. Seventh article distally widened, as long as third article, bearing four tufts of spines on inner- and latero-distal surface (Fig. 3 C). Eighth article bearing four tufts of spines on inner and lateral surface. Ninth article bearing three tufts of spines on inner surface, with seta on lateral surface. Terminal article curved, bearing two tufts of spines on lateral and inner surface, having simple spine and serrated lamina on distal margin, with outer seta. Terminal claw curved, with flattened inner surface (Fig. 3 D). Third leg granular, sparsely setose (Fig. 2 E). First coxa as wide as lateral processes, with anterodistal tubercle on first legs; anterodistal tubercle and posteroproximal nodulous ridge on second legs; anterior and posterior tubercles on third legs; small anterior and posterior tubercles on distal margin of fourth legs (Figs 2 A, B, 4 D). Second coxa elongated, longest among three coxae, with large curved tubercle on posterior surface. Third coxa slightly longer than first coxa, with several setae on ventral surface. Femur longest, with long seta on dorsodistal margin. First tibia as long as second tibia, with long seta on dorsodistal margin. Second tibia cylindrical, with long setae on dorso- and ventro-distal margin; dorsodistal seta longer than that of femur and first tibia. Tarsus short, approximately 1 / 6 length of propodus, with long seta on ventral surface. Propodus slightly curved, as long as tibiae, with several setae on dorsal surface, bearing six sole setae, without heel spine. Claw curved, 1 / 3 length of propodus. Auxiliary claws thin, 0.7 – 0.8 length of claw. Gonopores present on ventral surface of second coxa on fourth legs (Fig. 3 E). Measurements (mm). Holotype (NIBRIV 0000927835): Trunk length, 0.76; trunk width, 0.40; proboscis, 0.43; abdomen, 0.16. Paratype (NIBRIV 0000927837): Third leg, first coxa, 0.07; second coxa, 0.12; third coxa, 0.09; femur, 0.20; first tibia, 0.18; second tibia, 0.18; tarsus, 0.03; propodus, 0.17; claw, 0.05; auxiliary claw, 0.04.	en	Lee, Damin, Park, Jin-Ho, Park, Taeseo (2025): Description of new sand-dwelling Rhynchothorax species (Pycnogonida, Rhynchothoracidae) from Korean waters with note on novel morphological traits. Zoosystematics and Evolution 101 (4): 2055-2064, DOI: 10.3897/zse.101.167593
46D086CE5BE05E48AC9C004AB8765B3D.taxon	etymology	Etymology. The species name arenigenus is derived from the Latin “ arena (sand) + - genus (meaning ‘ arising from’ or ‘ born off’) ”, referring to its natural habitat on sandy bottoms. The Korean names for the family, genus, and species are all pronounced “ moraebadageomi ”, emphasizing the association with sandy environments.	en	Lee, Damin, Park, Jin-Ho, Park, Taeseo (2025): Description of new sand-dwelling Rhynchothorax species (Pycnogonida, Rhynchothoracidae) from Korean waters with note on novel morphological traits. Zoosystematics and Evolution 101 (4): 2055-2064, DOI: 10.3897/zse.101.167593
46D086CE5BE05E48AC9C004AB8765B3D.taxon	distribution	Distribution. This species is only known from the type locality, Jejudo Island, Republic of Korea.	en	Lee, Damin, Park, Jin-Ho, Park, Taeseo (2025): Description of new sand-dwelling Rhynchothorax species (Pycnogonida, Rhynchothoracidae) from Korean waters with note on novel morphological traits. Zoosystematics and Evolution 101 (4): 2055-2064, DOI: 10.3897/zse.101.167593
