Aplectana nordestina, Amorim, Darciane Maria De, Silva, Lidiane Aparecida Firmino Da, Morais, Drausio Honorio, Silva, Reinaldo José Da & Ávila, Robson Waldemar, 2017

Amorim, Darciane Maria De, Silva, Lidiane Aparecida Firmino Da, Morais, Drausio Honorio, Silva, Reinaldo José Da & Ávila, Robson Waldemar, 2017, Aplectana nordestina n. sp. (Nematoda: Cosmocercidae) parasitizing Leposternon polystegum (Squamata: Amphisbaenidae) from Northeastern, Brazil, Zootaxa 4247 (1), pp. 83-88 : 84-86

Aplectana nordestina n. sp. ( Fig. 1 )

Description. Small slender white nematodes, males slightly smaller than females. Triangular mouth surrounded by three lips, each one provided with a cuticular lamella on the anterior border, two papillae in each lip ( Fig. 1 D). Oesophagus starting with a short pharynx, elongated body, small isthmus and valved bulb. Excretory pore situated above the bulb. Lateral alae begin in the region of the nerve ring and end at the tail in both sexes. Cuticle with transverse striations from the posterior region to lips until the tip of the tail. Tapered conical tail. Anal protuberance present or absent.

Male ( Fig. 1 A), based on holotype and 13 paratypes: Body length 2.5 mm ± 0.2 mm (2.1 mm – 2.9 mm), width at midbody 190 ± 32 (146–241), total length of oesophagus 621 ± 67 (403–674); pharynx 46 ± 6 (39–61) long, isthmus 35 ± 6 (24–45) long, bulb 107 ± 17 (77–136) long. Width of bulb 115 ± 21 (85–156) and nerve-ring 202 ± 33 (134–261). Excretory pore 484 ± 77 (265–572) from anterior end of oesophagus. Tapered conical tail, with anal protuberance present or absent, 155 ± 17 (113–176) long from the opening of the cloaca to tip of tail. Unequal spicules in length ( Fig. 1 H): smaller spicule 84 ± 11 (66–94), large spicule 85.0 ± 9.7 (71–103), gubernaculum 46 ± 6 (37–57). Eleven pairs of caudal papillae ( Figs. 1 E; 1F): Precloacal: 4 pairs slightly symmetrically arranged, 1 pair close to the center and 1 pair next to one side of the cloaca; Adcloacal: 1 pair above the cloacal opening; Postcloacal: 2 pairs below the cloaca arranged in lateral pairs; Caudal: 4 papillae irregularly arranged in the middle of the tail.

Female ( Fig. 1 B), based on allotype and 12 paratypes: Body length 2.7 ± 0.4 mm (1.55 mm – 3.33 mm), width at midbody 172 ± 31 (120–215). Oesophagus 643 ± 74 (418–720) long, pharynx 41 ± 5 (35–52) long, isthmus 33 ± 4 (27– 43) and, and bulb 116 ± 21 (71–146) long. Width of bulb 123 ± 27 (66–165) and nerve ring 205 ± 29 (155–241). Distance of excretory pore from anterior 491 ± 34 (439–548). Distance from anterior end to vulvar opening 1.9 mm ± 0.2 mm (1.6 mm – 2.1 mm). Distance from posterior end to anus 170 ± 10 (144–184). Muscular ovijector directed anteriorly, 231 ± 44 (179–308) long, joining 2 uteri; 1 directed anteriorly and 1 posteriorly. Reproductive system absent from anterior third of body; posterior region of uterus flexed anteriorly before reaching anal region. Ovaries direct anteriorly, both lie anterior to vulva. Eggs absent in all specimens. Tail conical 167.0 ± 8.7 (162–179) with a terminal filiform prolongation, from the anus to the tip of the tail.

Taxonomic summary. Type host: Leposternon polystegum (Bahia Worm Lizard) - deposited in the Coleção Herpetologica da Universidade Regional do Cariri (URCA-H 5839); Collection date (05 January 2013).

Type locality: Trairi Municipality , Ceará State, Brazil, 39°25'W ; 03°42'S.

Site of infection: large intestine.

Voucher specimens: The holotype and allotype were deposited in the Coleção Parasitológica da Universidade Regional do Cariri (URCA-P 507 and 508), Crato, Ceará State, and paratypes in the Coleção Helmintológica do Instituto de Biociências ( CHIBB 7848 ; 7849; 7850), Botucatu , São Paulo State, Brazil .

Etymology. The specific epithet refers to region where the host was collected.

Remarks. To date, only nine species of Aplectana , including the new species, present spicules shorter than 120 µm: A. albae (61–63), A. herediaensis Bursey, Goldberg & Telford, 2006 (67–79), A. micropenis Travassos, 1925 (60), A. rysavi Barus & Coy Otero, 1969 (72), A. tucumanensis Ramallo, Bursey & Goldberg, 2008 (100), A. elenae Baker & Vaucher, 1986 , (97–116), A. tarija Ramallo, Bursey & Goldberg, 2007 , (110–120), and A. pusilla Miranda, 1924 (110). However, Aplectana nordestina n. sp. (66–103) presents a larger range in spicule length than the species cited above. Aplectana nordestina n. sp. is distinguished from these species by caudal papillae arrangement with 11 pairs of caudal papillae (6 precloacal, 1 adanal, and 4 postcloacal pairs). The new species can be distinguished from Aplectana tarija by the presence of a gubernaculum.

Aplectana nordestina n. sp. can be differentiated from the other known species in the genus by having 11 pairs of caudal papillae (6 precloacal, 1 adanal, and 4 postcloacal) and spicules (66–103) long, except from Aplectana crucifer Travassos, 1925 and Aplectana krausi Bursey & Goldberg, 2007 . From these species, Aplectana nordestina n. sp. is distinguished from A. crucifer by possessing a gubernaculum and having a shorter spicule (330) and from A. krausi by the distribution pattern of caudal papillae (5 precloacal, 1 adanal and 5 postcloacal pairs) and shorter spicules (159–182). All species of Aplectana infecting amphisbaenids have a small gubernaculum, A. albae (41–49), A. pusilla (49), A. raillieti (32), and A. tucumanensis (40) and Aplectana nordestina n. sp. (35–57), which seem to be a pattern for the species that parasitize amphisbaenids.

As stated above, A. alba and A. tucumanensis have spicules shorter than 100 µm, while A. pusilla and A. raillieti have longer spicules (110 µm and 230 µm, respectively) than Aplectana nordestina n. sp. (66–103). Caudal papillae arrangement is distinct from Aplectana nordestina n. sp. (6 precloacal, 1 ad-anal, and 4 postcloacal pairs) in those species: A. albae have 13–15 precloacal, 1 adanal, and 5 postcloacal pairs, A. raillieti , 17 precloacal, and 5 postcloacal pairs, A. pusilla have only 1 postcloacal and A. tucumanensis , possess 9 precloacal, 1 adanal, and 6 postcloacal pairs.

Figures

FIGURE 1. Aplectana nordestina n. sp. (A) male, entire and ventral view. (B) female, entire ventral view. (C) Nerve ring and excretory pore. (D) female, en face view. (E) male, posterior end, ventral view. (F) male, posterior end, lateral view. (G) female, vulva ventral view. (H) spicules and gubernaculum.