Physaloptera nordestina, Matias & Morais & Ávila, 2020

Matias, Cicera Silvilene Leite, Morais, Drausio Honorio & Ávila, Robson Waldemar, 2020, Physaloptera nordestina n. sp. (Nematoda: Physalopteridae) parasitizing snakes from Northeastern Brazil, Zootaxa 4766 (1), pp. 173-180 : 174-176

Physaloptera nordestina n. sp.

( Figs. 1 and 2 )

Description. Robust and filiform body, cuticle with transverse striations and dilated anteriorly forming a cephalic collarette ( Fig. 2A ). Sexual size dimorphism evident, with males smaller than females (1:0.61) and males with welldeveloped caudal alae. Longitudinal oral opening with the presence of two well-developed semicircular pseudolabia with transverse striations, with an external lateral tooth and an internal lateral tripartite tooth on each pseudolabium ( Figs. 1A , 2B ). Tripartite teeth composed of unequal subunits, including the two lateral ones with a rounded tip and a central one that is triangular. Four cephalic papillae in apical region and one pair of amphids ( Figs 1B and 2C ). Presence of a pair of deirids laterally ( Figs. 1C , 2D ). Esophagus long, with the muscular anterior part short and the glandular posterior part longer ( Fig. 1D ).

Males based on holotype and three paratypes: body length 10.6–19.5 mm, shorter than females, width at midbody 420–637 and nerve ring 299–480. Cephalic collarette present at anterior end, highly visible, at 43.5–55.9 from anterior extremity. Body width measured at the level of the cephalic collarette 143.2–191. Esophagus length 2.7–3.9 mm, muscular esophagus approximately 385–442 long by 79.8–99.9 wide, measured at the nerve ring level, and glandular esophagus approximately 3.9 mm long by 368.1 wide at the posterior region. Proportion of esophagus total length relative to body total length approximately 1:0.2. Distance from nerve ring to anterior end approximately 299–431.9, and body width at the level of nerve ring approximately 196.4–311.7. Distance from excretory pore to anterior end approximately 304–561 and body width measured at the level of excretory pore approximately 221.4–358.5. Posterior end ventrally curved in a spiral pattern with well-developed caudal alae, ornamented with an irregular, linear texture ( Fig. 2E ). Cloacal aperture at 929.1 from posterior extremity. Body width measured at the cloacal level approximately 862. Spicules sub-equal in size, with left spicule of a different shape. Left spicule 257–436 long ( Fig. 1F ) with globular dilation at distal end and pointed end, and right spicule 195–376 long ( Fig. 1G ), sword shaped and slightly pointed. Spicules ratio: body total length of approximately 1:0.02. Total of 21 caudal papillae: Ten pairs of papillae plus one unpaired papilla present on tail, with four pairs stalked and six pairs sessile. Of these, two pairs of lateral stalked papillae precloacal, one pair adcloacal and last one postcloacal. One pair of papillae precloacal and one single large papilla close to cloaca. Five pairs of sessile papillae postcloacal, with one pair of phasmids between the last pair of sessile papillae, smaller than other pairs ( Figs. 1H , 2D ).

Females larger than males, based on female allotype and seven paratypes: body length 16.3–32.1 mm and width at midbody 517.7–745. Cephalic collarette width 160.5–254.9, distant 52.3–75.4 from anterior extremity. Muscular esophagus 397.1–432 length and 96.4–116.1 width at the level of nerve ring, esophagus total length 288–484 and width 236.6–386. Nerve ring distant 269.7–460 from anterior extremity, with width 215.8–287.8. Excretory pore distant 397.1–588.2 from anterior extremity, with diameter of 242.9–306.4. Deirid distant 144.8–176.9 from anterior extremity. Didelphic uterus directed posteriorly, egg length 38.8–48.5 and width 21.0–25.4. Vagina muscular, with total length 778.2–985.6 and width 63.3–81.3, located at 4.3–4.8 mm from anterior extremity, without prominent lips ( Fig. 1E .). Tail 399–547 long and width 406.0, distance between deirids and tail 144.8–176.9. Tail rounded.

Taxonomic summary. Type host: Pseudoboa nigra (Duméril, Bibron & Duméril) : ( Squamata : Snake).

Other hosts: Oxybelis aeneus (Wagler) and Xenodon merremii (Wagler) : ( Squamata : Snake).

Type of locality: four states at Brazilian northeast: Ceará (Crato, Farias Brito, Icó and Nova Olinda municipalities), Pernambuco (Ouricuri municipality), Piauí (Piripiri municipality) Rio Grande do Norte (Ceará Mirim municipality) ( Fig. 3 ).

Site of infection: Stomach.

Voucher specimens: Holotype and allotype (URCA P—1075 and URCA P- 1076) and paratypes (URCA—P 478; 482; 484; 485; 492; 498; 511; 512; 515; 519; 520) deposited in the Coleção Parasitológica da Universidade Regional do Cariri, Crato municipality and (CHIBB—8841; 8842; 8843; 8844) Coleção Helmintológica do Instituto de Biociências de Botucatu—CHIBB, São Paulo State University (UNESP), Botucatu, São Paulo State, Brazil.

Etymology. The specific epithet refers to region where the hosts were collected.

Remarks. The new species was assigned to the genus Physaloptera based on the following characters: thick cuticle with striations; the presence of two triangular, well-developed pseudolabia, each with teeth on the free edge and cephalic papillae; the presence of a cephalic collarette; a cervical papilla posterior to the nerve ring; males with ornamented caudal alae connected ventrally, anterior to the cloaca; 21 caudal papillae, including four pedunculated and 13 sessile pairs (six surrounding the cloaca and three at tail); spicules sub-equal in size and with different shape; and females with the vulva located on the anterior third of the body and two to for uterine branches ( Chabaud 1975; Ortlepp 1922; Skrjabin & Sobolev 1964).

Physaloptera nordestina sp. n. is promptly distinguished from P. bainae , P. liophis and P. tupinambae , all of them parasites of Brazilian reptiles, by the number of caudal papillae (23, 23 and 22 respectively vs 21). Physaloptera bonnei , P. lutzi , P. monodens , P. obtusissima and P. retusa each possess 21 caudal papillae, but differ in the arrangement of the stalked papillae: P. bonnei , P. obtusíssima and P. retusa have two pairs of precloacal and two postcloacal, P. lutzi have two adcloacal and two postcloacal, while P. monodens and the new species have the same number and distribution of caudal papillae. However, in P. monodens the precloacal papillae differ in both size and distribution from the new species in having three papillae of the same size in P. monodens and a pair of papillae of the same size plus one large unpaired papilla in the new species ( Tables 1 and 2 ).

Figures

FIGURE 1. Physaloptera nordestina n. sp. (A) cephalic end, lateral view. (B) Cephalic end, dorsoventral view. (C) deirid. (D) Body shape with esophageal details. (E) Vulva and vagina, lateral view. (F) left spicule. (G) right spicule. (H) posterior end of male, showing bursa, ventral view.

FIGURE 2. Physaloptera nordestina n. sp. scanning electron micrographs. (A) body robust and striated. (B) Tooth shape. (C) Cephalic shape. (D) Deirid. (E) Tail shape in males. (F) Details of male tail.

FIGURE 3. Schematic map showing the localities where the hosts were collected.