Perspiria major, 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 : 496-501

Perspiria major sp. nov.

( Figures 4 , 5 ; Table 2 )

Holotype and paratype material

Two males and two females were collected from the subtidal zone of Bohai Bay . Holotype male on slide BHB40-(0-2)-2. Paratype male 2 on slide BHB40-(0-2)-7; female 1 on slide BHB04-(2-5)-8; female 2 on slide BHB41-(0-2)-3.

Holotype and paratype locality and habitat

Holotype male and paratype male 2 were collected from Station BHB40: 38.416 N, 118.140 E; depth 18 m; temperature 16.18°C; salinity 31.2 psu; silt sediment in the east of Bohai Bay. Female 1 was collected from Station BHB04: 38.964 N, 118.328 E; depth: 7 m; temperature: 14.9°C; salinity: 30.43 psu; silt sediment in the north of Bohai Bay. Female 2 was collected from Station BHB41: 38.533 N, 118.91 E; depth: 18 m; temperature: 15.9°C; salinity: 32.0 psu; silt sediment in the east of Bohai Bay.

Etymology

The species is named in reference to its relatively large body for the genus.

Measurements

All measurement data are given in Table 2 .

Description

Holotype male. Body cylindrical with blunt anterior end and tapered tail end. Cuticle striated, beginning from the level of the middle of amphideal fovea. Inner labial sensilla not observed, six outer labial sensilla papilliform, four cephalic setae thin, about 8 μm long, located level with the middle of the amphideal fovea. Two latero-dorsal and two latero-ventral longitudinal rows of 5–6 cervical setae (4–6 μm long), somatic setae short, arranged irregularly on the surface of the body. Amphideal fovea unispiral, about 7 μm in diameter, i.e. 37% of the corresponding body diameter, and 5 μm from the anterior end. Buccal cavity minute, with a small dorsal tooth. Pharynx 124 μm long, cylindrical, with an oval anterior bulb and a pyriform terminal bulb. Cardia small, conical. Nerve ring located at about 75% of pharyngeal length from anterior end. Ventral gland and excretory pore not observed. Tail conico-cylindrical with prominent transverse striations except its terminal end, 2.5 times cloacal body diameter. Three caudal glands present.

Reproductive system with single outstretched testis. Spicules arcuated without ventral velum, 1.2 cloacal body diameters long, proximal end enlarged, heart-shaped, and distal end tapered. Gubernaculum plate-shaped, 10 µm long, broadest in middle portion and tapering proximally and distally, without apophysis. Precloacal supplements absent.

Females. Similar to males in most morphological characters except the body slightly larger. 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 55% of body length from anterior end.

Differential diagnosis and discussion

The species is characterised by the presence of four longitudinal rows of 5–6 cervical setae, small unispiral amphidial fovea, partially surrounded with cuticular striation ( Figures 4 (a), 5(b)); conical buccal cavity with a small dorsal tooth; pharynx with an oval anterior bulb and a pyriform terminal bulb; spicules arcuated with heart-shaped proximal end and tapered distal end, without ventral velum. Gubernaculum plate-shaped without apophysis. Precloacal supplement absent. Tail relatively short, conico-cylindrical with prominent transverse striations.

The new species is most similar to P. megamphida Vincx and Gourbault, 1989 in having a short tail that is shorter than 3 times cloacal body diameter. However, the new species differs from the latter species by its much smaller amphidial fovea (37% of corresponding body diameter vs more than 60%); the presence of the dorsal tooth (vs absence) and longer body length (1914–2241 μm vs 1605 μm). The difference between the new species and its congeners can be inferred from the key below.

Updated key to all valid species of Perspiria including the new species

1. Presence of somatic papillae along the body.................................................................. P. lara

- Absence of somatic papillae along the body............................................................................ 2

2. Male with precloacal supplements................................................................................................ 3

- Male without precloacal supplements ......................................................................................... 5

3. 11–12 tubular precloacal supplements, tail filiform, 8.5–11.2 a.b.d. long ......................... .................................................................................................................................................. P. flagellata

- 14–17 cup-shaped or papillary precloacal supplements, tail conico-cylindrical, shorter than 8 a.b.d.............................................................................................................................................. 4

4. Amphidial fovea circular, precloacal supplements cup-shaped...................... P. papillata

- Amphidial fovea longitudinal loop-shaped, precloacal supplements papilliform........... ........................................................................................................................ P. macramphida sp. nov.

5. Cuticle striations resolvable into dots............................................................ P. septentrionalis

- Cuticle striations prominent, not resolvable into dots .......................................................... 6 6. Buccal cavity with two dorsal teeth..................................... ..................................... P. elongata

- Buccal cavity with only one dorsal tooth or no tooth at all................................................ 7

7. Proximal end of spicules markedly hook-shaped......................... ......................... P. hamata

- Proximal end of spicules not hook-like........................................................................................ 8

8. Tail filiform, longer than 9 a.b.d...................................................................................................... 9

- Tail conico-cylindrical, shorter than 8 a.b.d.............................................................................. 11

9. Spicules without ventral velum, gubernaculum with dorsal apophysis.............................. ......................................................................................................................................... P. striaticaudata

- Spicules with ventral velum, gubernaculum without dorsal apophysis....................... 10

10. Tail 11.9–14.5 a.b.d. long, slender spicule with triangular proximal end............................ ........................................................................................................................................ P. longicaudatus

- Tail 9–10 a.b.d. long, thick spicule with rounded or club-shaped proximal end.. ........ ......................................................................................................................................................... P. mokii

11. Tail 6–7.3 a.b.d. long, spicules 36–40 μm................................ ................................ P. boucheri

- Tail shorter than 3 a.b.d., spicules 51–55 μm .......................................................................... 12

12. Amphidial fovea large, 60% c.b.d., buccal cavity without tooth..... ..... P. megamphida

- Amphidial fovea small, 37% c.b.d., buccal cavity with dorsal tooth .................................... ........................................................................................................................................ P. major sp. nov.

Figures

Figure 4. Perspiria major sp. nov. Male holotype (a, d, e) and female paratypes (b, c): (a, c) lateral view of anterior body portion, showing cephalic setae, amphid, buccal cavity with tooth, cervical setae and pharyngeal bulbs; (b) entire view of female, showing vulva and ovaries; (c) lateral view of female pharyngeal region; (d) magnification drawing of spicules and gubernaculum; (e) lateral view of posterior body portion, showing tail, spicules and gubernaculum.

Figure 5. Perspiria major sp. nov. holotype (a, d) and paratypes (b, c, e): (a, c) lateral view of anterior portion, showing cephalic setae and amphidial fovea; (b) lateral view of pharyngeal region, showing small dorsal tooth (arrow) and pharyngeal bulb;(d) lateral view of male posterior portion, showing tail, spicules and gubernaculum; (e) magnification of spicules; (f) middle region of female, showing vulva and eggs. Scale bars: a, c = 20 µm; b = 15 µm; d, f = 50 µm; e = 10 µm.