Ptycholaimellus ocellatus, Huang & Wang, 2011

Huang, Y. & Wang, J. Y., 2011, Two new free-living marine nematode species of Chromadoridae (Nematoda: Chromadorida) from the Yellow Sea, China, Journal of Natural History 45 (35 - 36), pp. 2191-2201 : 2192-2196

Ptycholaimellus ocellatus sp. nov.

( Figures 1 , 2 )

Type material

Five males and five females were measured and studied. Holotype: ♂ 1 on slide LUL08994; paratypes: ♂ 2, ♀ 3 on slide LUL 08994; ♂ 3, ♀ 5 on slide LUL08993; ♂ 4, ♂ 5, ♀ 2, ♀ 4 on slide LUL08991; ♀ 1 on slide LUL 08992.

Type locality and habitat

Intertidal muddy sediment and algae at Lianyungang coast of Jiangsu province (34 ◦ 42’ N, 119 ◦ 30’ E) .

Etymology

This species is named after the presence of ocelli.

Measurements

Measurements are given as follows, see also Table 1.

Holotype ♂ 1

– 152 M 704 800 µm; a = 27.6, b = 5.3, c = 8.3, Spic = 36 µm

12272922

Paratype ♀ 1

– 160 V 776 870 µm; a = 27.2, b = 5.4, c = 9.3, V% = 49%

12303223

Notes: de Man a, body length/max. body diameter; a.b.d., anal body diameter; de Man b, body length/pharynx length; de Man c, body length/tail length; c.d., corresponding diameter; V%, position of vulva from anterior end expressed as a percentage of total body length.

Description

Males. Body cylindrical, abruptly narrowing at a third of pharynx length towards the anterior end and gradually tapering towards the posterior end ( Figures 1B,D and 2A ). Head region separated from rest of the body by a narrow constriction (collar). Ventral gland opens into this collar through a large ampulla connected to opening by a slender duct.

Cuticle homogeneously annulated with transverse rows of punctations. Two longitudinal rows of thick elongated dots at about 3 µm apart that extend from the anterior to the tail end ( Figures 1A and 2C ). Somatic setae not seen. Prominent round ocelli (about 3 µm in diameter) at either subdorsal side of anterior end, 17–19 µm from anterior end.

Amphidial fovea invisible. Inner and outer labial sensillae inconspicuous; four short cephalic setae, about 3 µm (1/4 h.d.) long and located at the same level. Stoma has a large S-shaped dorsal hollow tooth. Pharynx cylindrical, about 155 µm long and with a buccal bulb and a well-developed posterior double bulb which is 26% of the length of pharynx and 22 µm in diameter at the middle ( Figure 2B ). Nerve ring located at 55% of the length of pharynx from the anterior end. Ventral gland very large, located at the anterior part of the intestine.

Tail about 4.3 a.b.d. long, conical with a long distinct spinneret ( Figure 2D ).

Reproductive system monorchic with an outstretched testis located to the right of the intestine ( Fig. 1D ). Spicules 33–39 µm (1.6 a.b.d.) long, arcuate and cephalate proximally. Gubernaculum simple rod, about half as long as the spicules (16–20 µm), curved and parallel to the distal end of the spicules ( Figure 1F and 2D ). Pre-cloacal supplement absent.

Females. Similar to males in most respects, except for the slightly larger body. Reproductive system amphidelphic with two tapering, reflexed ovaries ( Figure 1B ), anterior branch located to the right of the intestine and the posterior one located to the left. Vulva located at about midpoint of body length.

Differential diagnosis

Ptycholaimellus ocellatus sp. nov. is characterized by the presence of ocelli at both subdorsal sides of anterior end, an abruptly narrowing anterior cervical region, a cuticle with transverse rows of punctations and a lateral differentiation with two longitudinal rows of thick elongated dots, and voluminous ventral gland with a large ampulla. The new species is closely related to Ptycholaimellus adocius Dashchenko and Belogurov, 1984 in possessing ocelli, but the latter has longer cephalic setae (2/3 h.d. long), and a cervical region not abruptly narrowing. This new species is similar to Ptycholaimellus ponticus Filipjev, 1922 in the shape and size of the body, spicules and gubernacula, but it is easily identified by the prominent ocelli and abruptly narrowing anterior cervical part.

Figures

Figure 1. Ptycholaimellus ocellatus sp. nov. (A) Lateral view of female anterior end; (B) lateral view of female body, showing vulva and ovary; (C) lateral view of male anterior end; (D) lateral view of male body, showing ventral gland cell and testis; (E) lateral view of male tail end, showing spicule and gubernacula; (F) spicules and gubernaculum.

Figure 2. Ptycholaimellus ocellatus sp. nov. (A) Lateral view of female body; (B) lateral view of male anterior end, showing buccal cavity, ocellatus and double bulb; (C) lateral surface view of male anterior end, showing lateral punctation and ocellatus; (D) lateral view of male tail end, showing spicules and gubernaculum.