Admirandus capibaribei, Cavalcanti & Guilherme & Rosa-Filho, 2023

Cavalcanti, Mariana Da Fonseca, Guilherme, Betânia C. & Rosa-Filho, José Souto, 2023, Review of Admirandus Belogurov & Belogurova, 1979 (Nematoda, Oncholaimidae) with the description of a new species and the first record of the genus from Brazil, Zootaxa 5244 (1), pp. 71-81 : 73-74

Admirandus capibaribei sp. n.

( Figures 1–4 , Table 1 )

Material studied. Holotype: male (slide MOUFPE.NEM-1)

Paratypes: 2 paratype males (one male in slide MOUFPE.NEM-7 and one male in slide MOUFPE.NEM-8) and 6 paratype females (one female in slide MOUFPE.NEM-2, one female in slide MOUFPE.NEM-3, two females in slide MOUFPE.NEM-4, one female in slide MOUFPE.NEM-5 and one female in slide MOUFPE.NEM-6). The specimen in the slide MOUFPE.NEM-2 is the female paratype represented in the images ( Figures 2 and 4 ) .

Etymology: The species epithet is related to the sampling location, i.e., the estuary of the Capibaribe River. The name Capibaribe originates from the Tupi language and means “in the water of the capybara or ‘wild pigs’”, through the junction of the terms from the Tupi language kapibara (capybara), y (water) and pe (in).

Description

Males ( Figures 1 and 3 ): Body cylindrical, tapering slightly anteriorly to a conical-cylindrical tail. Cuticle smooth. Six small inner labial papillae, six outer labial, and four cephalic setae. Horseshoe-shaped marginal lamellae (in lateral view) at level of cephalic setae. Stoma rectangular in shape, length to width ratio 2.4–2.8. Three onchia in buccal cavity: largest right, subventral, with a row of denticules, dorsal and left ventrosublateral onchia smaller and equal in size. Amphidial fovea pocket-like with slit-like aperture 3.0–3.5 times body diameter. Pharynx cylindrical, surrounding buccal cavity anteriorly, wider at base, but not forming bulb. Nerve ring covering approximately 50% of pharyngeal length. Cardia large, triangular in shape. Secretory-excretory pore opening anterior to nerve ring, with ventral gland located posterior to cardia. Reproductive system diorchic, with opposed and extended testes, at right side of intestine. Spicules short, slightly curved, arc length 0.9–1.1 of anal body diameter. Gubernaculum without apophysis. Cloaca surrounded by circle of short setae. Tail 2.6–3.3 diameter of anal body, conical-cylindrical in shape, with cylindrical part ratio of 1.3–1.5. One pair of setae mid-tail and second pair at tail extremity. Three caudal glands in pre-cloacal region with openings in the spinneret.

Females ( Figures 2 and 4 ): Females similar to males in general, differing only in some aspects (b and c ratios) and sexual dimorphism of tail. Amphidial fovea pocket-like with slit aperture 3.8–4.3 times diameter of body. Ovaries paired, reflected antidromously, left of intestine, with egg. Vulva in the 43–53% total body length. Demanian system of Adoncholaimus type with osmosium, ductus uterinus, ductus entericus, uvette, main duct, interstitial channel and three terminal pores in the tail region. Tail 3.8 anal body diameter, conical-cylindrical in shape, attenuated transition between conical and cylindrical parts. Single terminal setae and spinneret.

Diagnosis of Admirandus capibaribei sp. n. Demanian system of the Adoncholaimus type with osmosium, ductus uterinus, ductus entericus, uvette, main duct, interstitial channel and three terminal pores in caudal region. Presence of denticles at level of dorsal tooth. Spicules short (0.9–1.1 of anal body diameter). Tail conical-cylindrical with terminal setae. Tail sexually dimorphic.

Remarks. Lo Russo et al. (2016) described Admirandus sanjuliensis as having one pre-cloacal terminal copulatory pore and two post-cloacal pores, although the principal trait that distinguishes Admirandus from Adoncholaimus is the position of these pores. In this case, sanjuliensis does not align with Admirandus , and based on the evidence, should be considered to be a species inquirenda.

While specimens identified as Adoncholaimus have been recorded from Brazil, there is no previous record of Admirandus from this country ( Venekey et al. 2010; Fonseca & Fehlauer-Ale 2012; Pinto et al. 2013; Venekey 2017). Given this, the description of Admirandus capibaribei sp. n. represents the first record of the genus in Brazil.

Figures

FIGURE 1. Admirandus capibaribei sp. n. male. A: General view, showing the tip of the anterior testis (arrow). B: head, showing the outline of the pocket-shaped amphid (arrow). B’: head showing the dorsal tooth, denticles, and secretory-excretory pore (arrow). C: tail with spicules, gubernaculum and cloacal setae. Scale bars: A = 200 µm; B, B’ and C = 50 µm.

FIGURE 2. Admirandus capibaribei sp. n. female. A: General view, showing the uvette of the demanian system (arrow). B: region of the head, showing the pocket-shaped outline of the amphid and secretory-excretory pore (arrows). B’: region of the head, showing the teeth. C: region of the tail region, showing the anus and the pores of the Demanian system (arrows). Scale bars: A = 200 µm; B, B’, and C = 50 µm.

FIGURE 3. Admirandus capibaribei sp. n. male:A: general view. B: Head. B’: buccal cavity, showing the nerve ring and secretory–excretory pore. C: secretory–excretory gland. D: tail, showing the spicules, gubernaculum and caudal glands. Scale bars: A = 200 µm; B, B’, C, and D = 50 µm.

FIGURE 4. Admirandus capibaribei sp. n., female:A: general view. B: buccal cavity. B’: head. C: Gonad with an egg and part of the demanian system. D: Tail showing the pores of the demanian system. Scale bars: A = 200 µm; B, B’, and C = 100 µm; D = 50 µm.