Physaloptera apodemi, Wang & Zhang, 2020

Wang, Yuhuan & Zhang, Luping, 2020, Physaloptera apodemi sp. nov. (Nematoda: Physalopteridae) from Apodemus sylvaticus (Linnaeus, 1758) (Rodentia: Muridae) from Tianjin, China, Zoological Systematics 45 (4), pp. 259-265 : 260

Physaloptera apodemi sp. nov. ( Figs 1–3 )

General description. Body large and robust, females larger than males. Cuticle thick with distinct transverse striations, forming a distinct cephalic collarette near anterior end ( Fig. 2A ). Oral opening surrounded by two semicircular pseudolabia, each pseudolabium provided with two large cephalic papillae, one small amphid, an externolateral tooth and three internolateral teeth ( Figs 2 A–B). Internal lateral teeth dissimilar in shape, two lateral teeth with rounded tip, central tooth triangular ( Fig. 2B ). Oesophagus divided into short anterior muscular part and long posterior glandular part. Nerve ring located at posterior end of muscular oesophagus. Cervical papillae located at level of anterior end of glandular oesophagus ( Fig. 1A ). Excretory pore posterior to cervical papillae.

Description. Male (n = 10). Body length 13.67–18.29 (15.85)mm. Maximum width 786–1143 (942); body width at level of nerve ring 223–553 (377). Muscular oesophagus 427–563 (475) long; glandular oesophagus 2.21–2.91 (2.54) mm. Total length of oesophagus 2.83–3.38 (3.01) mm, 16.78–21.95% (19.31%) total body length (TBL) from anterior end. Nerve ring 388–466 (436) from anterior end; cervical papillae 689–845 (775) from anterior end; excretory pore 777–922 (843) from anterior end. Posterior end of body ventrally curved in spiral with ornamented caudal alae which unite on ventral surface of body ( Figs 3 A–B). Ventral surface of cloacal region with prominent longitudinal ridges ( Figs 3 B–C). Cloacal aperture 619– 990 (801) from posterior extremity. Twenty-two total caudal papillae including four pairs of pedunculated papillae organized laterally at caudal alae, three sessile papillae just anterior to cloaca, and five pairs of post-cloacal sessile papillae and one single sessile papilla ( Figs 1H , 3B ) with following distribution: two pairs of papillae immediately posterior to cloaca; third pair located below, with inclined orientation; fourth and fifth pairs equidistant, parallel; and one single papilla located between fifth pair of papillae ( Figs 1H , 3 C–F). A pair of phasmids located anterior to fifth pairs of post-cloacal papillae ( Fig. 3F ). Spicules unequal and dissimilar, left spicule longer and thinner than right one, both left and right spicules with striated sheaths in their proximal end. Left spicule 451–525 (481) long, with a pointed tip. Right spicule 352–397 (375) long, with a blunt tip ( Figs 1F , 3D ). Gubernaculum absent.

Female (n = 10). Body length 24.45–32.57 (29.41) mm. Maximum width 1191–1714 (1423); body width at level of nerve ring 379–534 (448). Muscular oesophagus 485–621 (566) long; glandular oesophagus 3.22–4.08 (3.59) mm. Total length of oesophagus 3.78–4.56 (4.09) mm, 12.83–15.45% (14.33%) TBL from anterior end. Nerve ring 466–553 (502) from anterior end; cervical papillae 786–1214 (936) from anterior end; excretory pore 884–1390 (982) from anterior end. Vulva located at anterior fifth of body, 4.52–7.71 (5.68)mm from anterior end, and 16.78–24.11% (19.68%) TBL from anterior end ( Fig. 2C ). Vagina extending anteriorly for a short distance then bending backward, extending posteriorly and connecting with two uteri ( Fig. 1E ). Eggs ellipsoidal with thick shell, 39–44 (42) long, 21–27 (24) wide. Tail conical, 505–631 (562) long ( Figs 1G , 2D ).

Type host. Wood mice, Apodemus sylvaticus (Linnaeus, 1758) ( Rodentia : Muridae )

Site of infection. Stomach.

Prevalence. 50% (5 of 10 hosts examined)

Mean intensity. 12 (7–20 worms per host)

Material examined. Holotype male (HBNU-M-2001), National Baxianshan Nature Reserve, Ji County, Tianjin, China (40°12'N, 117°32'E), 12 Aug. 1982, coll. Zhaozhi Qiu. Paratypes. 9 males (HBNU-M-2002) and 10 females (HBNU- M- 2003), same data as holotype .

Etymology. The specific name derives from the generic name of the host.

Figures

Figure 1. Physaloptera apodemi sp. nov. A. Anterior end of female, ventral view, arrow indicating cervical papillae. B. Right cervical papilla of female, ventral view. C. Excretory pore of male, lateral view. D. Egg. E. Vulva region, lateral view. F. Spicules. G. Posterior end of female, lateral view. H. Posterior end of male, ventral view. Scale bars: A, E, G–H =0.10 mm; B–D, F=0.05mm.

Figure 2. Scanning electron micrographs of Physaloptera apodemi sp. nov., female. A. Cephalic end, apical view, showing the cephalic papillae (cp), amphid (a) and cephalic collarette (cc). B. Part of pseudolabia, apical view, showing externolateral tooth (ELT) and internolateral teeth (ILT). C. Anterior part of body, showing vulva. D. Posterior end of body, ventral view. Scale bars: A =50μm; B=25μm; C=400μm; D=250μm.

Figure 3. Scanning electron micrographs of Physaloptera apodemi sp. nov., male. A. Posterior end of body, lateral view. B. Posterior end of body, ventral view, showing pedunculated papillae (pp) and sessile papillae (pos or prs). C. Cloacal region, showing pedunculated papillae (pp), three pre-cloacal sessile papillae (prs) and first and second post-cloacal sessile papillae (pos1, pos2). D. Enlarged cloacal region, showing first and second post-cloacal sessile papillae (pos1, pos2), left spicule (LS) and right spicule (RS). E. Third pair of post-cloacal sessile papillae (pos3) and fourth pair of post-cloacal sessile papillae (pos4). F. Fifth pair of post-cloacal sessile papillae (pos5), post-cloacal single sessile papilla (poss) and a pair of phasmids. Scale bars: A–B=300μm; C=50μm; D–F=30μm.