Aporcelaimellus insularis, Andrássy, 2004

Andrássy, I., 2004, Two New Species Of Aporcelaimellus Heyns, 1965 (Nematoda: Dorylaimida) From The Tropics, Acta Zoologica Academiae Scientiarum Hungaricae 50 (2), pp. 97-107 : 101-107

publication ID	https://doi.org/ 10.5281/zenodo.12586875
persistent identifier	https://treatment.plazi.org/id/03FD5D51-E97C-FFAF-5417-375B99ACFD01
treatment provided by	Felipe
scientific name	Aporcelaimellus insularis
status	sp. nov.

Treatment

Aporcelaimellus insularis View in CoL sp. n.

( Figs 3 C–D View Fig , 6 A–D View Fig and 7 A–C View Fig )

Holotype female: L = 1.39 mm; a = 18; b = 3.7; c = 57; c’ = 0.6; V = 54 %. Odontostyle 28 µm.

Paratype females (n = 8): L = 1.20–1.46 mm; a = 14–18; b = 3.3–3.9; c = 63–70; c’ = 0.5–0.6; V = 52–54 %. Holotype female on slide No. 14793. Paratypes: twenty-one females and eleven juveniles. Type locality and habitat: Le Niol, Seychelle Islands , 300 m above sea-level, moist soil from rocks. – Further localities on Seychelle Islands: Morne Blanc, 500 m above sea-level, rain forest, soil with roots; Praslin, Vallee de Mai, detritus from rocks; collected June 2000 by L. HUFNAGEL .

Body very robust, 68–96 µm wide at mid-region, in consequence of fixation C- or G-shaped. Cuticle smooth, 2.5–3.0 µm thick and 5.5–7.0 µm thick on dorsal side of tail, consisting of the two usual layers of different refraction; inner layer thicker than outer. Labial region 18–20 m wide (a’ = 65–80), set off by a deep constriction. Lips more or less fused, rounded. Body at posterior end of stylet 1.9–2.0 times, at posterior end of oesophagus 3.4–4.2 times as wide as head. Amphid more than half as wide as corresponding body.

Odontostyle strong, 28–30 µm long and 5 µm thick, 1.4–1.5 times as long as labial width, 7.8–8.0% of oesophagus length, much thicker than cuticle; its ventral wall about twice as thick as dorsal wall. Guiding apparatus aporcelaimoid, dorsally thicker than ventrally. Oesophagus 360–406 µm long, occupying 26–30% of body length, muscular in its entire length, fairly suddenly widened at 43–48%. Glandularium 148–188 µm long. Out of the oesophageal gland nuclei, the dorsal nucleus and the two posterior sublateral nuclei are most conspicuous. Dorsal nucleus at 15–17% of entire length of body. Cardia conoid with a dorsal unicellular body. Distance between posterior end of oesophagus and vulva as long as or somewhat shorter than oesophagus. Intestine, especially in its posterior half, heavily folded. Prerectum often very spacious, thin-walled, short, 1.0–1.8, rectum 1.0–1.5 anal body widths long.

Female. Amphidelphic with equally developed gonads occupying 28–32% of body length. Vulva transverse with strongly sclerotized, heart-shaped inner lips (sclerotized pieces). Vagina (together with vulval lips) 29–33 µm, occupying one-third or more of body width. Each gonad 2.4–2.8 times as long as body diameter. In younger females (without eggs) each branch of uterus hardly longer than one body width. Oviducts short and narrow. One egg at a time, 78–80 × 40–45 µm, nearly as long as body width. Spermathecae in egg-bearing females filled with oval spermatozoa. Vulva–anus distance 25–33 times as long as tail. Tail quite short, only half the anal body diameter, ventrally convex, dorsally initially also convex, but near the tip becoming profoundly concave, provided with a 4–6 µm long, sharply offset, dorsally bent conoid peg.

Male. Not observed.

Juvenile. Its tail is quite similar to the female tail.

( DITLEVSEN, 1928); H: A. malagasi HEYNS, 1996 ; I: A. stilus ( KIRJANOVA, 1951)

Diagnosis. A very robust, middle-sized species with offset head, strong stylet, aperture occupying half of the stylet length, at middle enlarged oesophagus, heart-shaped vulval lips, short and wide prerectum and with short, dorsally concave tail possessing a dorsally curved peg.

It shall be emphasized that the structure of the tail appears as if it is very permanent within this species: all the 22 females and 11 juveniles studied show the same tail shape.

Remarks. Aporcelaimellus insularis sp. n. belongs to the short-tailed (c’ shorter than 1) members of the genus, and among them, to those possessing a mammillate tail. They are A. gerlachi ( MEYL, 1956), A. kikereensis BAQRI et COOMANS, 1973 , A. krygeri ( DITLEVSEN, 1928) HEYNS, 1965 , A. malagasi HEYNS, 1996 , A. paracentrocercus ( DE CONINCK, 1935) BAQRI et COOMANS, 1973 and A. stilus ( KIRJANOVA, 1951) ANDRÁSSY, 1986. In its very characteristic tail structure, the new species is clearly distinguished from each species listed above (see Figs 7 A–C View Fig , 4 A–I View Fig and 5 A–I View Fig ). Furthermore, it differs from gerlachi: body shorter (vs. 1.9–2.2 µm), stylet longer (vs. 20–21 µm), prerectum shorter (vs. 3.5–4.0 anal body diameters), tail shorter (vs. c’ = 1) and other shaped; from kikereensis : vulva more anterior (vs. 60–61%), tail shorter (vs. c’ = 1) with sharply separate peg; from malagasi : body shorter (vs. 2.2–3.3 mm), cuticle without punctuation, stylet comparatively longer (vs. 1.0–1.1 labial diameters long) with shorter aperture (vs. two-thirds of stylet length), terminal peg of tail offset and dorsally directed; from krygeri : body shorter (vs. 2.5–3.0 mm), a’ value smaller (vs. 110–115), tail peg offset and dorsally bent; from paracentrocercus: body smaller (vs. 1.8–1.9 mm), gonads much shorter (vs. 40–50% of body length), terminal peg shorter and dorsally curved; from stilus: body shorter (vs. 1.9–2.3 mm), oesophagus longer (vs. b = 4.5–4.8), terminal peg offset and dorsally directed.

Etymology. The species name insularis (Latin) means: island-inhabiting, or an islander, and refers to the type locality, the Seychelles, where this new species seems to be generally distributed.