Aplectana minaensis Vieira & Gonçalves & Lima & Sousa & Muniz-Pereira 2020, n. sp.
Creators: name: Vieira, Fabiano Matos
name: Gonçalves, Paula Araujo
name: Lima, Sueli De Souza
name: Sousa, Bernadete Maria De
name: Muniz-Pereira, Luís Cláudio
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Secernentea
Ascaridida
Cosmocercidae
Aplectana
Aplectana minaensis

description: Aplectana minaensis n. sp.
(Figs. 1 and 2)
General. Small nematodes. Sexual dimorphism evident, with males slightly smaller than females. Lateral alae present in both sexes (Figs 1A, B, 2A). Lateral alae beginning anterior to the nerve ring (Figs. 1A, B) and terminating posterior to the cloaca in males (Figs. 1 C–E), and anterior to the anus in females. Cuticle transversely striated (Figs. 2B, C). Mouth opening triangular (Figs. 2B, C), surrounded by distinct triangular lips (Figs. 2 B–E). Dorsal lip with two large apical and two small basal sessile papillae (Figs. 2 B–D); each of the lateroventral lips with one large apical ventral sessile papilla, two small basal sessile papillae, and one lateral amphid (2C, E). Oesophagus with oesophageal bulb (Figs. 1A, B). Excretory pore located anterior to oesophageal bulb (Figs. 1A, B). Nerve ring anterior to the excretory pore, at level of oesophageal corpus (Figs. 1A, B).
Male (based on holotype and seven specimens; measurement of holotype in parentheses): Body length 2.25–3.38 (2.9) mm, maximum width 168–338 (290). Total length of oesophagus 737–825 (735); pharynx 48–55 (50) long, corpus 478–645 (620) long, oesophageal bulb 105–130 (115) long and 105–145 (145) wide. Distance of nerve ring 155–240 (155), and excretory pore 415–745 (635) from anterior end. Spicules slightly equal and well developed, with rounded pointed at distal end (Fig. 1C). Left spicule 400–605 (565) and right spicule 413–600 (600) in length. Gubernaculum weakly sclerotized, with triangular shape (Fig. 1F), 53–70 (68) in length. Tail 125–200 (180) long. Few somatic papillae distributed irregularly from the level of nerve ring up to caudal region. Caudal papillae 12 pairs, of which 4 pairs of ventral precloacal papillae, the last two pairs located on anterior margin of cloaca; one large unpaired papilla between the two last precloacal pairs; 2 pairs of lateral ad cloacal papillae; 6 pairs of post cloacal papillae, first, second and third pairs ventral, arranged horizontally side by side, fourth pair ventral subsequent to the first three, fifth pair laterodorsal, posterior to the alae; sixth pair ventral, near the most tapered part of the tail. Papillae pattern: 4+1:2:6 (Figs 1B, D, E, 2F, G).
Female (based on allotype and eight specimens; measurement of allotype in parentheses): Body length 2.7–3.98 (3.9) mm, maximum width 330–410 (410). Total length of oesophagus 760–901 (760); pharynx 47–55 (55) long, corpus 565–700 (565) long, oesophageal bulb 124–150 (140) long and 140–240 (170) wide. Distance of nerve ring 200–328 (275), and excretory pore 340–590 (340) from anterior end. Tail conical with posterior part ending in a fine filament (Fig. 1G), 260–450 (420) long. Few somatic papillae distributed irregularly from the level of nerve ring up to caudal region. Vulva post equatorial, 2.14–2.79 (2.34) mm from anterior end, muscular ovijector directed anteriorly (Fig 1H). Ovaries two, prodelphic. Uterus with non-larvated eggs, with thin shelled oval (Fig 1I), length 95–130, width 58–93.
Taxonomic Summary
Type Host: Amphisbaena alba Linnaeus (Squamata: Amphisbaenidae) (red worm lizard, cobra de duas cabeças)
Site of infection: Intestinal caecum
Intensity of infection: 32 specimens
Type Locality: Municipality of Juiz de Fora (21º76’S, 43º21’ W), state of Minas Gerais, Brazil Type specimens: Holotype male: CHIOC 38972 a. Allotype female: CHIOC 38972 b. Paratypes: CHIOC 38972 c (3 males and 3 females).
Etymology: The specific name refers to the name of the State of the type locality of the new species, “ Minas Gerais ”.
Remarks. Species of Aplectana mainly parasitize amphibians and some species of reptiles worldwide. They are characterized by having somatic papillae, lateral alae, the tail of males without rosettes or plectanes, and females prodelphic with many eggs in the uteri (Baker 1987, Anderson et al. 2009, Bursey et al. 2018a).
We assigned the nematodes of the current study to the genus Aplectana due to the following characteristics: Well developed lateral alae (Fig 1 A–E, 2A), numerous minute somatic papillae, three large lips with four submedian large cephalic papillae (2B–E), one pair of lateral amphids (2B–C), an oesophagus with a short pharynx a cylindrical corpus and oesophageal bulb, and an excretory pore anterior to the oesophageal bulb (Figs 1A,B). The prodelphic female present ovaries anterior to the vulva, and males present two equal spicules (Gibbons 2010).
The Aplectana species are differentiated by the presence or absence of an unpaired papilla on the cloacal anterior border in males, and the presence or absence of a gubernaculum. However, the size of male body structures and the number and arrangement of caudal papillae can also differentiate these nematodes (Bursey et al. 2018a, b). Currently, 58 nominal species of Aplectana are recognized (Amorimn et al. 2017, Gomez et al. 2017, Bursey et al. 2018a, b, Sou et al. 2018, Sou & Banerjee 2020, current study). Aplectana minaensis n. sp. belongs to a group of species that present both a gubernaculum and an unpaired papilla on the anterior border of the cloaca (Table 3). The species composing this group are: A. chamaeleonis (Baylis), A. degraaffi Baker, A. courdurieri Chabaud & Brygoo, A. albae Adamson & Baccam, A. elenae Baker & Vaucher, A. membranosa (Schneider), A. paraelenae Baker & Vaucher, A. raillieti Travassos, A. zweifeli Moravec & Sey, A. leesi Hristovki & Riggio, A. linstowi Yorke & Maplestone, A. hamatospicula Walton, and A. nebulosa Gomez, González & Sanabria (see Gomez et al. 2017, Bursey et al. 2018a) (Table 3).
We can separate the Aplectana species presenting gubernaculum and unpaired precloacal papillae in two groups: species with less than 20 pairs of caudal papillae and those with more than 20 pairs. Aplectana minaensis n. sp. fits the first group, since it presents 12 pairs of caudal papillae. Besides the species described here, only A. nebulosa present unpaired precloacal papillae, a gubernaculum, and posterior region with less than 20 pairs of caudal papillae. This species occurs in the Argentine anuran Pleurodema nebulosum (Burmeister, 1861) (Anura: Leptodactylidae) (Gomez et al. 2017). Aplectana minaensis n. sp. can be distinguished from A. nebulosa by the total number of caudal papillae (12+1 vs. 13–14+1, respectively); the number and arrangement of postcloacal papillae (6 pairs of papillae, with 1st to 4th pairs ventral, 5th laterodorsal, 6th ventral vs. five pairs of papillae, with 1st and 2nd ventral, 3rd lateral, 4th ventral, 5th lateral, respectively); the size of spicules (413–600 vs. 85–126, respectively); the position of the end of lateral alae in males (postcloacal, at the level of 4º pair vs. precloacal, at the level of 3º pair of papillae) (Table 1).
description: Published as part of Vieira, Fabiano Matos, Gonçalves, Paula Araujo, Lima, Sueli De Souza, Sousa, Bernadete Maria De & Muniz-Pereira, Luís Cláudio, 2020, A new species of Aplectana Railliet & Henry (Nematoda: Cosmocercidae) in Amphisbaena alba Linnaeus (Squamata: Amphisbaenidae) from Minas Gerais State, Brazil, pp. 234-244 in Zootaxa 4890 (2) on pages 235-239, DOI: 10.11646/zootaxa.4890.2.4, http://zenodo.org/record/4301855