Setosabatieria hilarula de Man, 1922

Hong, Jung-Ho, Kim, Hyeonggeun, Kim, Kichoon, Lee, Seunghan & Lee, Kanghyun Lee and Wonchoel, 2023, Two unrecorded species of the family Comesomatidae Filipjev, 1918 (Nematoda: Araeolaimida) from Korea, Journal of Species Research 12 (2), pp. 122-149 : 139-145

Setosabatieria hilarula de Man, 1922

( Figs. 6-8, Table 4)

A B D C E

D

Locality. The coast of Sokcho: sub-tidal northern part of East Sea, Korea (38°12′42″N, 128°37′39″E, at a depth of 35 m, in the slightly gravelly sandy mud.

Material. Four males (NIBRIV0000900847-NIBRIV 0000900850) and three females (NIBRIV0000900853, NIBRIV0000900855, NIBRIV0000900856) were collected by Sangjin Kim along the Sokcho coast on 12th September 2012, from Research Vessel Hansudan 1.

Measurements. See Table 4 for detailed measurements and morphometric ratios.

Description. Male ( Figs. 6, 8 , Table 4). Body cylindrical, slender, gradually tapering toward both extremities. Cuticle thin, with faint, relatively fine cross striations throughout body. Punctuation in cuticle not visible. Tail conico-cylindrical.

Anterior sensilla in three separate crowns, six inner and outer labial sensilla small, with papillae form. Four cephalic setae of nearly equal length, 12.0-13.2 μm long. Cephalic setae located 0.4 head diameter from anterior end. Cervical setae 10-16 μm long, arranged in two latero-dorsal and two latero-ventral longitudinal files of six to thirteen setae and situated at 18-80 μm from anterior body end. Amphidial fovea large, circular multispiral. Fovea coiled ventrally, in about 3.25-3.50 turns.

Buccal cavity very tiny, cup-shaped, its walls not sclerotized and not differentiated, teeth not observed. Pharynx long (248-290 μm) and slender, cylindrical. Nerve ring located at 140-157 μm (54.1-56.4%) of pharyngeal length from anterior end. Ventral gland pore just posterior nerve ring, situated at 162-194 μm of pharyngeal length from anterior end. Cardia round, small (8-13 μm), surrounded with intestinal tissue. Ventral gland cell body placed posterior of cardia.

Reproductive system diorchic, testes outstretched, anterior testis (situated right mid-gut) located 1398-1674 μm and posterior testis (situated left mid-gut) located 551-1030 μm from the cloaca. Spicules paired, equal and arcuate, 60-75 μm long as arc (1.2-1.5 abd). Gubernaculum sclerotized pieces, proximal portion slightly bent, bearing dorso-caudal apophysis (19-25 μm), surrounding spicules. Sixteen to eighteen minute mid-ventral supplementary papillae observed in precloacal region, several copulatory muscles located in pre-cloacal supplement region. First precloacal supplement situated about 14-22 μm from anus and most anterior precloacal supplement located about 190-353 μm from anus. Tail consisted proximal conical and distal cylindrical part (125-156 μm). Tail 5.2-5.7 abd long with three long terminal setae (about 9-18 μm long), three caudal glands, and prominent spinnerret. Other tail setae (about 8-15 μm) arranged in approximately four dorso- and ventrolateral longitudinal rows.

Females ( Figs. 7 , 8 , Table 4). Similar to male, except body larger than male (females maximum body diameter average 82 μm wide). Vulva at 44.9-51.5% of body of length. Didelphic, outstretched ovaries, anterior ovary (situated left mid-gut) 508-702 μm, posterior (situated right mid-gut) 470-549 μm long. Supplements absent.

Diagnosis. Setosabatieria . Body length 1888-2529 μm; a 23.9-41.0; b 7.8-9.4; c 7.5-9.8; c′ 5.2-6.0. Cephalic setae 11.5-13.5 μm. Cervical setae 10-16 μm long, 6-13 setae per files. Spicules curved, 60-75 μm long in arc. Thin gubernacular apophysis dorso-caudally, 19-25 μm long. Sixteen to eighteen minute precloacal supplements present. Tail conico-cylindrical, 192-300 μm long, cylindrical portion 49-57%.

Remarks. Setosabatieria hilarula can be separated from S. conicaudata by its conico-cylindrical tail shape. Setosabatieria australis differs from S. hilarula by spicule shape (L-shaped vs curved). Setosabatieria hilarula can be distinguished from S. coomansi , S. fibulata , S. jingjingae , S. major , S. orientalis and S. triangularis by the presence leaf-like extensions of the cuticle lateral to cloaca. Setosabatieria singaporensis is dissimilar to S. hilarula by the shape of gubernacular apophysis (respectively, bent in the proximal portion vs long and thin vs short). Setosabatieria longiapophysis can be differentiated from most other species of the genus by having spicules with long straight apophysis.

The present population of Setosabatieria hilarula resembles that of de Man, 1922 in general characters. They slightly differ from by the number of precloacal supplements (16-18 vs 11-16), the relative length of tail (c′: 5.2-6.0 vs 4.2-5.6) and the posterior portion of tail (49-57% vs 25-50%). We consider such differences as intraspecific variation.

Figures

Fig. 8. Setosabatieria hilarula de Man, 1922 from East Sea, Korea: A. male head, paratype; B. male copulatory apparatus, paratype; C. male tail, paratype; D. female vulva, paratype. Scale bars: 20 μm(A, B) and 50 μm (C, D).

Fig. 7. Setosabatieria hilarula de Man, 1922 from East Sea, Korea, female 1: A. pharynx; B. head; C. tail; D. vulva; E. habitus. Scale bars: 20μm (A-C), 50 μm (D) and 100 μm (E).