Pheronous donghaiensis Chen and Guo 2015
Creators: name: Lee, Hyo Jin
name: Rho, Heegab Lee and Hyun Soo
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Enoplea
Enoplida
Ironidae
Pheronous
Pheronous donghaiensis

description: Pheronous donghaiensis Chen and Guo, 2015
(Figs. 4-6; Tables 3, 4)
Pheronous donghaiensis Chen and Guo, 2015, p. 156, Figs. 4, 5.
Material examined. One male (MABIK NA00157738), in glycerin on HS slide, was deposited in the nematode collection at the specimen conservation room of the Marine Biodiversity Institute of Korea (MABIK), Seochun, Korea. Three males (KIOST NEM - 1 - 2656, KIOST NEM - 1 - 2657, KIOST NEM - 1 - 2658) and three females (KIOST NEM - 1 - 2659, KIOST NEM - 1 - 2660, KIOST NEM - 1 - 2661), in glycerin on HS slide, were deposited in the nematode collection at the specimen conservation room of the Bio-Resources Bank of Marine Nematodes (BRBMN), East Sea Research Institute, Korea Institute of Ocean Science & Technology (KIOST), Korea. All the specimens were collected from Mallipo Beach, Sowonmyeon, Taean-gun, Chungcheongnam-do, Korea, 22 June 2020 (leg. by HS Rho and H Lee).
Habitat. Intertidal fine sand beach (36°47′15.00″N, 126° 08′29.00″E).
Measurements. See Table 3 for detailed measurements and morphometric ratios.
Description. Males. Body long and cylindrical (2,004 - 2,180 μm long), tapering sharply at posterior extremity (Fig. 4A). Maximum body diameter at mid body level 53 - 55 μm. Cuticle smooth. Head diameter 28 - 30 μm wide, distinctly separated from rest of body by a constriction behind cephalic sensilla. Lip region relatively flatted, with six-minute rounded inner labial papilla. Head sensilla papilliform, six outer labial sensilla (3 μm long) and four cephalic sensilla (3 μm long) arranged in one circle, stout and blunt (Figs. 4C, 6A). Buccal cavity divided into two parts: anterior one conical shaped and posterior one cylindrical tube-shaped with enfolded cuticularized wall. Four solid curved claw-like teeth present at margin of anterior conical section and inner wall of conical section covered minute denticles in rows (Figs. 4C, 6A). Amphideal fovea pocket-shaped, about 16 - 18 μm wide, situated at posterior edge of cephalic groove (Fig. 6B). Anterior pharynx region surrounding buccal cavity distinctly swollen; general cylindrical structure posteriorly slightly wider toward end portion. Pharynx cylindrical, 341 - 373 μm long, corresponding body diameter 47 - 50 μm. Nerve ring located on 142 - 149 μm from anterior end, corresponding body diameter 42 - 44 μm, situated at 40 - 42% of pharynx length (Fig. 4B). Tail significantly tapered toward posterior end; tip of tail with a sharp point. Tail with a series of three pairs of small curved tubular supplements situated at subventral post-cloacal region in two rows (Figs. 4D, 6C, F). Reproductive system diorchic with two opposed testes. Spicules paired, consist of thick and cuticularized walls, with central septum at proximal end. Gubernaculum relatively thinner at proximal end; distal end thick with hookshaped (Figs. 4D, 6D). Eight to nine precloacal supplements small, curved tubular-shaped, situated at subventral region in two rows (Figs. 4E, 6E).
Females. Similar to males in general appearance but differ in slightly longer tail length (c = 18 - 21 vs. c = 21 - 25) and sexual characteristics (Figs. 5A, B, 6G). Body 2,114 - 2,197 μm long; cylindrical body distinctly tapered toward posterior end. Maximum body diameter 57 - 60 μm. Amphideal fovea pocket-shaped, about 17 - 19 μm wide, 10 μm long, situated at cephalic papilla levels (Figs. 5D, 6H). Reproductive system didelphic; ovaries opposed and reflexed. Anterior ovary situated on right side of intestine, posterior one on right side of intestine (Fig. 5C). Vulva 1,196 - 1,269 μm from anterior end, situated at 57 - 58% of total body length (Fig. 6I). Tail 105 - 118 μm long, about 2.9 - 3.2 times of anal body diameter. Tail with several papillae randomly arranged and tip of tail sharp pointed (Figs. 5E, 6J).
All measurements are in μm.
Remarks. The genus Pheronous was established by Inglis in 1966 with the type species, P. ogdeni. It is distinguished from other genera of the family Ironidae by the presence of all papilliform anterior sensilla, relatively short spicules, conical tail with pointed tip, and the absence of caudal glands (Inglis, 1966; Platt and Warwick, 1983; Chen and Guo, 2015) So far, only two species, P. ogdeni Inglis, 1966 and P. donghaiensis Chen and Guo, 2015, have been described in this genus. Morphological and ecological characteristics of the genus Pheronous including the Korean P. donghaiensis are given in Table 4.
Pheronous donghaiensis was firstly described from intertidal sandy sediments on the Huangcuo coast, Xiamen City and Dongshan Island of the East China Sea. Pheronous donghaiensis is characterized by a well-developed buccal cavity with four claw-like solid teeth and minute denticles, relatively short and thick spicules with central septum, the presence of 8 - 9 curved tubular-shaped precloacal supplements, tail tapers to a sharp point with three small tubular supplements arranged into two rows in males, and the absence of caudal glands.
The present Korean specimens of P. donghaiensis are clearly distinguished from P. ogdeni by the relatively long body length (2,004 - 2,180 μm vs. 1,490 - 1,980 μm in males; 2,114 - 2,197 μm vs. 1,430 - 1,770 μm in females), the number of precloacal supplements (8 - 9 vs. 4), the shape of pre- and postcloacal supplement (curved tubular-shaped vs. papilla-shaped), and the presence of central septum in spicules (absent in P. ogdeni). The present Korean specimens are most like the original description by Chen and Guo (2015) in the following features, such as the shape of copulatory systems in males, the presence of 8 - 9 tubular precloacal and three postcloacal supplements, and the presence of thick spicules with central septum. However, the Korean specimens of P. donghaiensis are not in accord with the original description by the relatively longer spicules length (54 - 61 μm vs. 33 - 46 μm).
Distribution. China (Chen and Guo, 2015) and Korea (Present study).
description: Published as part of Lee, Hyo Jin & Rho, Heegab Lee and Hyun Soo, 2023, Two new records of free-living marine nematodes of the family Ironidae de Man, 1876 (Nematoda: Enoplida) from Korea, pp. 55-67 in Journal of Species Research 12 (1) on pages 63-66, DOI: 10.12651/JSR.2023.12.1.055, http://zenodo.org/record/12753323