Aberrapex catarinensis Quadros 2024, sp. nov.
Creators: name: Quadros, Alex L.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Cestoda
Lecanicephalidea
Aberrapecidae
Aberrapex
Aberrapex catarinensis

description: Aberrapex catarinensis sp. nov.
(Figs. 3B, 4C, 6C, D, 7, 8)
Type host: Myliobatis goodei Garman, southern eagle ray; (Myliobatiformes: Myliobatidae).
Type locality: off Santa Catarina (29°03’02.88” S, 48°19’32.16” W), Brazil, southwestern Atlantic.
Site of infection: Spiral intestine.
Specimens deposited: Holotype (mature worm) MZUSP 8045, 12 paratypes (mature worms) MZUSP 8046 a– 8046l, two SEM strobilar vouchers MZUSP 8047, 8048, one voucher of proglottid cross-section series MZUSP 8049 a, proglottid cross-section series MZUSP 8049 b–8049e and 11 paratypes (mature worms) HWML 217599– 217609.
Etymology: The specific epithet, catarinensis, refers to the type locality of this species registered in Santa Catarina State, Brazil.
Description. Based on 24 complete mature worms, one cross-sectioned worm and two specimens prepared for SEM.
Worms 2.16–5.2 mm (3.13 mm ± 0.83 mm; 24) long, maximum width at level of terminal proglottid (Fig. 3B), euapolytic, 36–65 (45 ± 7.2; 24) proglottids per worm. Scolex 125–157 (138 ± 8.7; 19) long, 217–253 (235 ± 10.7; 21) wide, consisting of four bothridiate acetabula; apical modification of scolex proper and apical organ absent (Figs. 7A, 8A, B). Acetabula cup-shaped, 113–136 (124 ± 6.7; 20; 24) long, 102–135 (115 ± 8.5; 20; 24) wide (Figs. 7A, 8A, B). Cephalic peduncle absent.
Apex of scolex covered with acicular filitriches (Fig. 8C). Proximal and distal acetabular surface covered with hastate spinitriches and acicular filitriches (Fig. 8D, E); hastate spinitriches only covering anterior 2/3 of distal acetabular surface (Fig. 8B). Proglottids covered with acicular to capilliform filitriches (Fig. 8F).
Proglottids craspedote, weakly laciniate, with four laciniations (two dorsal, two ventral), less evident in mature proglottids (Figs. 3B, 7B). Immature proglottids 35–63 (43 ± 7.0; 24) in number, initially wider than long, becoming longer than wide with maturity; posterior-most immature proglottid 194–392 (314 ± 48.3; 24) long, 142–305 (229 ± 48.1; 24) wide. Mature proglottids 1–2 (N = 24) in number; terminal mature proglottids in which testes are not degenerated 534–908 (701 ± 124.4; 19) long, 156–270 (216 ± 37.9; 19) wide (Fig. 7B); terminal fully mature proglottids in which most testes are degenerated 796–1148 (983 ± 157.6; 5) long, 204–296 (240 ± 38.9; 5) wide (Fig. 4C).
Testes 12–26 (20 ± 3.1; 24) in number, 32–62 (48 ± 6.4; 24; 43) long, 61–97 (81 ± 9.1; 24; 43) wide in mature proglottids, arranged in 2–3 irregular columns in dorsoventral view (Fig. 7B), in single field extending from anterior margin of proglottid to ovary, slightly overlapping anterior margins of ovary, one row deep in cross-section (Fig. 6C), degenerated in some terminal mature proglottids (Fig. 4C). Vas deferens in maturing proglottids in form of thin tube, sinuous, extending along lateral margin of proglottid from ootype to cirrus sac, entering cirrus sac at distal end (Fig. 7B, C); vas deferens in proglottids in which testes are degenerated enlarged to form conspicuous external seminal vesicle (Fig. 4C). External seminal vesicle extensive, sinuous, extending almost medially in proglottid from level of ootype to level of anterior margin of cirrus sac. Internal seminal vesicle absent. Cirrus sac pyriform, 75–140 (92 ± 18.1; 17) long, 33–80 (54 ± 12.2; 17) wide in mature proglottids with testes, 124–150 (136 ± 10.3; 5) long, 83–110 (92 ± 11.0; 5) wide in mature proglottids in which most testes are degenerated, containing coiled unarmed cirrus (Fig. 7B).
Ovary H-shaped in dorsoventral view (Fig. 7B, C), tetralobed in cross-section (Fig. 6D), lobulated, symmetrical, 67–166 (106 ± 34.1; 17) long, 65–134 (90 ± 16.0; 17) wide in mature proglottids with testes; 161–339 (237 ± 74.5; 5) long, 89–125 (105 ± 15.2; 5) wide in mature proglottids in which most testes are degenerated; ovarian isthmus at middle of ovary. Mehlis’ gland at posterior margin of ovary (Fig. 7B, C). Vagina slender, extending along lateral margin of proglottid from ootype to genital atrium, opening into genital atrium posterior to cirrus sac (Fig. 7B, C). Genital pores lateral, irregularly alternating, 72–80% (76% ± 2.3%; 19) of proglottid length from posterior margin in mature proglottids with testes, 77–85% (81% ± 3.0%; 5) in mature proglottids with degenerated testes.
Uterus saccate, sinuous, extending along midline of proglottid from anterior margin of ovary to level of posterior margin of cirrus sac, curved porally (Fig. 7B); uterine duct not observed. Vitelline follicles in two columns (one dorsal, one ventral) on each lateral margin of proglottid, extending entire length of proglottid, interrupted by ovary and cirrus sac, slightly overlapping anterior and posterior margins of ovary (Fig. 7B, C); vitelline follicles 6–15 (9 ± 2.6; 19; 36) long, 10–34 (18 ± 6.2; 19; 36) wide in mature proglottids with testes, 10–13 (11 ± 1.1; 5; 10) long, 20–39 (27 ± 9.0; 5; 10) wide in mature proglottids with degenerated testes. Eggs not observed. Single pair of excretory ducts.
Remarks. Aberrapex catarinensis sp. nov. can be distinguished from A. arrhynchum, A. ludmilae, A. panamensis, A. manjajiae and A. weipaensis by the length of the scolex (125–157 long vs 165–205, 160–190, 71–102, 82–101 and 40–63 long, respectively), and from A. senticosus by the width of the scolex (217–253 long vs 125–170). In addition, the vas deferens in A. catarinensis sp. nov. can be in form of an external seminal vesicle, whereas in A. ludmilae and A. arrhynchum an external seminal vesicle has not been observed. Aberrapex catarinensis sp. nov. can further be distinguished from A. senticosus, A. panamensis, A. manjajiae and A. weipaensis by the microthrix pattern. Aberrapex catarinensis sp. nov. has hastate spinitriches covering the anterior 2/3 of the distal acetabular surface, whereas in A. panamensis and A. senticosus hastate spinitriches cover the entire distal acetabular surface, in A. manjajiae the hastate spinitriches are restricted to the central region of the acetabula, and in A. weipaensis they are lacking on the distal acetabular surface altogether. Aberrapex catarinensis sp. nov. differs from A. sanmartini and A. vitalemuttiorum based on its greater number of proglottids (36–65 vs 26–30 and 26–32, respectively). In addition, in A. catarinensis sp. nov. the external seminal vesicle extends from ootype near the anterior margin of the cirrus sac, whereas in A. vitalemuttiorum it extends from ootype to well anterior to the cirrus sac. Finally, A. catarinensis sp. nov. also differs from A. sanmartini based on length of the terminal mature proglottids in which testes are not degenerated (534–908 long vs 225–350).
description: Published as part of Quadros, Alex L., 2024, Two new American species of Aberrapex (Eucestoda: Lecanicephalidea: Aberrapecidae) from myliobatid stingrays (Batoidea: Myliobatidae), pp. 85-101 in Zootaxa 5448 (1) on pages 91-96, DOI: 10.11646/zootaxa.5448.1.5, http://zenodo.org/record/11231233