Aporcelaimellus amazonicus, 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 : 98-101

publication ID	https://doi.org/ 10.5281/zenodo.12586875
persistent identifier	https://treatment.plazi.org/id/03FD5D51-E979-FFA1-5400-30659986FB88
treatment provided by	Felipe
scientific name	Aporcelaimellus amazonicus
status	sp. nov.

Treatment

Aporcelaimellus amazonicus View in CoL sp. n.

( Figs 1 A–D View Fig , 2 A–C View Fig and 3 A–B View Fig )

Holotype (female): L = 1.62 mm; a = 25; b = 3.5; c = 41; c’ = 1.1; V = 49 %. Odontostyle 26 µm . Paratype (females) (n = 2): L = 1.63–1.73 mm; a = 21–23; b = 4.3–4.4; c = 36–41; c’ = 1.0–1.5; V = 44–45%. Holotype female on slide 14772. Paratypes: two females. Type locality and habitat: Iquitos in Brazil, primary rain forest along the River Amazonas, soil from around trees, collected November 1971 by J. BALOGH .

Body plump, C-shaped after fixation, in anterior half hardly, in posterior half more strongly curved, 65–77 µm wide at mid-region. Cuticle smooth, 2.8–3.5 µm in most part of body and 4.4–4.8 µm on dorsal side of tail. Under optical microscopy, it consists of two layers (especially distinct on tail), of which the outer layer is thin and more transparent, the inner layer thicker and more “solid” and of other refraction. Labial region 18–19 µm wide (a’ = 85–96) *, sharply set off by a constriction; lips moderately separated from one another, more or less angular. Body at posterior end of stylet 1.7–1.9 times, at posterior end of oesophagus 3.5–4.5 times as wide as head. Amphid almost as wide as two-thirds of corresponding body diameter.

Odontostyle strong, 24–26 µm long and 4.5–5.0 µm thick, or 5.7–6.3% of oesophagus length, 1.3–1.4 times as long as labial width, and twice as thick as cuticle at the same level. Ventral wall of stylet thicker than dorsal wall. Aperture equal to half length of stylet. Guiding apparatus aporcelaimoid, its ring surrounding the first quarter of stylet. Oesophagus 380–450 µm, occupying 23–28% of entire length of body, its anterior section also muscular, gradually enlarging at 47–51% of its length. Oesophageal gland nuclei more or less conspicuous; dorsal nucleus at 15% of body length. Glandularium 130–180 µm long. Cardia elongate-conoid, dorsally with a separate unicellular body

Oesophageal gland nuclei in Aporcelaimellus amazonicus

D = 60–66% AS 1 = 20–22%

AS 2 = 34–35%

PS 1 = 63–68%

K = 59–63% PS 2 = 66–70% (gland?). Distance between posterior end of oesophagus and vulva 1.0–1.3 times as long as oesophagus. Prerectum short and spacious, 1.7–2.4, rectum 1.1–1.6 times anal body diameter.

Female. Amphidelphic with equally developed gonads. Vulva transverse, with strongly sclerotized but unusually narrow, 9 µm long inner lips. Whereas, vagina very thick; vulva + vagina equal to 24–29 µm, or occupying about one-third of body diameter. Each genital tract 2.6–3.2 body widths long, occupying 12–13% of body length. Each uterine branch about 1.5 body widths long, oviduct transversely striated, proximal with spermatheca-like swelling; the latter and uterus separated by a sphincter muscle from each orther. Neither eggs, nor sperms were observed. Distance vulva–anus equal to 18–22 tail lengths. Female tail 40–48 µm, one to one and a half times as long as anal body diameter, 2.4–2.8% of body length, conoid-rounded with sharply pointed terminal projection. Ventral contour of tail convex, dorsal contour concave; projection 10–13 µm long, slightly or strongly bent dorsally. Two pairs of subdorsal caudal papillae lying close to each other.

Male. Not found.

Diagnosis. A middle-sized, rather robust nematode species with sharply separated head, strong stylet, aperture occupying half of the stylet length, an oesophagus widening at its middle, comparatively back positioned dorsal nucleus, slender vulval lips, thick vagina, and with 1.0–1.5 anal body diameters long, sharply pointed tail.

Remarks. By virtue of the characteristic shape of tail: possessing a comparatively long and sharply tipped projection, Aporcelaimellus amazonicus sp. n. is unique within the genus. Among the members of Aporcelaimellus , 18 species are known each showing concave contour on the dorsal side of tail. If we compare the tail of the present Brazilian species with the tails of those illustrated in Figures 4 A–I View Fig and 5 A–I View Fig , it can be seen that A. amazonicus is immediately differentiated from each of them. In other words, a tail showing such a long, well separated and sharply pointed tip nowhere occurs within the genus. Another distinguishing character is found in the shape of the sclerotized vulval lips which are longer and narrower than is usual in the genus.

MEYL (1956 and 1957) described two Aporcelaimus species from Brazil which were later transferred to Aporcelaimellus : A. gerlachi ( MEYL, 1956) HEYNS, 1965 and A. seinhorsti ( MEYL, 1957) HEYNS, 1965. In comparing the three Brazilian species, we see that our new species differs from gerlachi in having a shorter body (1.6–1.7 mm compared with 1.9–2.3 mm), non-punctuated cuticle, longer stylet (24–26 µm compared with 20–21 µm), more anterior vulva (at 44–49% compared with 53–56%) and sharply pointed tail. It differs from seinhorsti in having a shorter and plumper body (1.6–1.7 mm, a = 21–25 compared with 2.35 mm, a = 33), smooth cuticle, longer stylet (1.3–1.4 labial widths compared with one labial width), and pointed tip of tail.

Etymology. The species is named after Amazonia, the greatest rain forest region on Earth.