Perspiria macramphida, Zhai & Shi & Li & Sun, 2023

Zhai, Hongxiu, Shi, Yifeng, Li, Ting & Sun, Jun, 2023, Two new species of genus Perspiria (Desmodoridae: Nematoda) from the Bohai Bay of China, Journal of Natural History 57 (9 - 12), pp. 490-502 : 493-496

Perspiria macramphida sp. nov.

( Figures 2 , 3 ; Table 1 )

Holotype and paratype material

Three males and two females were obtained from the subtidal zone of Bohai Bay . Holotype male and paratype female 1 on slide BHB16-(0-2)-10. Paratype male 2 on slide BHB16-(0-2)-9; paratypes male 3 and female 2 on slide BHB06-(2-5)-6.

Holotype and paratype locality and habitat

Holotype male, paratype male 2 and female 1 were collected from Station BHB16: 38.589 N, 117.774 E; depth: 6 m; temperature: 14.9°C; salinity: 31.2 psu; silt sediment in the west of Bohai Bay. Other paratypes were collected from Station BHB06: 38.748 N, 118.504 E; depth: 21 m; temperature: 17.8°C; salinity: 31.596 psu; silt sediment in the middle of Bohai Bay.

Etymology

The species name is from the Latin macros (great) and amphid, referring to its large amphideal fovea.

Measurements

All measurement data are given in Table 1 .

Description

Holotype male. Body cylindrical with rounded anterior end. Cuticle striated, beginning from the middle of the amphideal fovea and ending at tail tip. Inner labial sensilla papilliform. Six outer labial sensilla setiform, about 2 μm long. Four cephalic setae about 10 μm long, located at the level of the anterior border of the amphideal fovea. Four subcephalic setae 8 μm long, located at anterior to posterior border of the amphideal fovea, about 10 µm from the cephalic setae ( Figures 2 (a), 3(b)). Somatic setae not found. Amphideal fovea unispiral, longitudinal loop-shaped, 15 μm long and 12 μm wide, i.e. 60% of the corresponding body diameter, about 7 μm from the anterior end. Buccal cavity conical, with a small dorsal tooth. Pharynx cylindrical with a pyriform terminal bulb. Cardia small, conical. Nerve ring and excretory system not observed. Tail conico-cylindrical with prominent transverse striations except its terminal end, 4.3 times cloacal body diameter long. Three caudal glands present.

Reproductive system with one outstretched testis. Spicules slender, arcuated with ventral velum, 1.9 times as long as cloacal body diameter. Proximal end enlarged, and distal end tapered. Gubernaculum 19 μm long, without apophysis. Sixteen papillary precloacal supplements, evenly spaced.

Females. Similar to males in most morphological characters. Reproductive system didelphic, with two opposed and reflexed ovaries. Anterior ovary located to the right of intestine, posterior ovary to the left of intestine. Spermathecae not observed. Vagina straight, cuticularised, about 0.2 times vulval body diameters long. Vulva raised, situated on ventral side of mid-body, about 50% of body length from anterior end.

Differential diagnosis and discussion

The present species is characterised by cuticle with annulations along the body, amphidial fovea unispiral, longitudinal loop-shaped, partially surrounded with cuticular striations ( Figures 2 (a), 3(a)); conical buccal cavity with a dorsal tooth; pharynx with a pyriform terminal bulb; tail conico-cylindrical; spicules strongly curved with enlarged proximal end and ventral velum; 16 papillary precloacal supplements, evenly spaced.

Among 11 known valid species within the genus, only Perspiria flagellata Vitiello, 1971 and Perspiria papillata Vincx and Gourbault, 1989 have precloacal supplements. The new species is most similar to P. papillata in having 15–16 precloacal supplements and the similar de Man ratio ̍a̾, ̍b̾. However, the new species can be distinguished from the latter species by the shape of the amphidial fovea (longitudinal loop-shaped vs circular); much longer spicules (53–61 µm vs 35 µm); and obviously shorter tail (c̾ = 3.6–4.3 vs 7.4). The new species is also similar to P. megamphida in having a relatively large amphidial fovea and relatively short tail length (shorter than 3 times cloacal body diameter in the latter species). However, the new species can be easily distinguished from the latter species by the shape of the amphidial fovea (longitudinal loop-shaped vs rounded), the presence of precloacal supplements (vs absence), spicules with ventral velum (vs absence), buccal cavity with tooth (vs absence) and much slenderer body (a = 49–59 vs 31.1). The difference between the new species and its congeners can be inferred from the key below.

Figures

Figure 2. Perspiria macramphida sp. nov. Holotype (a, b, d, g) and paratypes (c, e, f): (a) Lateral view of anterior body portion, showing cephalic setae, subcephalic setae, loop-shaped amphidial fovea, buccal cavity with small tooth and pharyngeal bulb; (b) entire view of male; (c, d) lateral view of male posterior portion, showing spicules, gubernaculum and precloacal supplements; (e) entire view of female, showing vulva and ovaries; (f) anterior end of male, showing cephalic setae, sub-cephalic setae and buccal cavity with one small dorsal tooth; (g) magnification of spicules and gubernaculum.

Figure 3. Perspiria macramphida sp. nov. holotype: (a) lateral view of pharyngeal region, showing cephalic setae and amphid; (b) lateral view of anterior end, showing buccal cavity and small dorsal tooth; (c) lateral view of male posterior portion, showing conico-cylindrical tail and spicules; (d) lateral view of male cloacal region, showing spicules and gubernaculum; (e) magnification of precloacal supplements. Scale bars: a = 20 µm; b–e = 30 µm.