Hypodontolaimus portuguese, Pinto & Neres, 2020

Pinto, Taciana Kramer & Neres, Patricia Fernandes, 2020, Four new species of free-living nematodes from shallow continental shelf of Portugal, Zootaxa 4722 (1), pp. 1-33 : 4-10

Hypodontolaimus portuguese sp. n.

( Figures 2–5 , Table 2 )

urn:lsid:zoobank.org:act:67FE8663-A666-432F-889F-935657EDB2D7

Type material: five males and one female were collected at stations 8,11 and 28. Holotype (♂) MUHNAC / MB 26– 000022 . Paratype (♀) MUHNAC / MB26–000023 Other paratypes: UFALPEN/ LEB 001–004

Type Locality. Coarse sand sediments, up to 20 m depth ( Table 1 ).

Etymology. The specific epithet “portuguese” is given due to the locality where it was found and as homage to Portugal.

Measurements. Table 2 .

Description. Male. Body robust, 624–736 µm long with maximum body diameter 30.5–66 µm. Annulated cuticle with transversal rows of small dots. Lateral longitudinal differentiation represented by an interruption between two larger dots. This pattern is homogeneous along entire body.Anterior end rounded and not set off. Both inner and outer labial setae inconspicuous. Four cephalic setae measuring 44% of corresponding body diameter. Amphideal fovea difficult to see, probably transverse slit-like. Buccal cavity armed with a large S-shaped dorsal tooth measuring 12–18 µm from its tip to base of buccal cavity. A well sclerotized thickened plate, 5.5–6.0 µm long, is also present in the dorsal region of the buccal cavity anteriorly to the tooth. Pharynx with terminal bulb, occupying only 4–6% of the body. Its anterior section surrounds the stoma. Basal bulb well developed occupying 72% of the corresponding body diameter. Excretory pore at cephalic setae level. Reproductive system with single outstretched testis. Spicules 0.6–1.0 times the cloacal body diameter, curved and slightly cephalated. Gubernaculum and pre-cloacal supplements absent. Tail conical (3–4 times the cloacal body diameter) with a small spinneret.

Female. Similar to male in almost all aspects except for higher tooth length (21µm) a higher cephalic setae length (18 µm). Reproductive system amphidelphic with reflexed ovaries with branches bent to opposite directions. Vulva located near midbody region (53%).

Diagnosis. Hypodontolaimus portuguese sp. n. is characterized by a unique blend of features present in other species of the genus, mainly the absence of precloacal supplements and gubernaculum and inconspicuous amphideal fovea.

Differential diagnosis. Hypodontolaimus portuguese sp. n. is similar to H. golikovi in the absence of gubernaculum and supplements, however, H. golikovi has very diminutive cephalic setae, about 6 times smaller than Hypodontolaimus portuguese sp. n. and rounded and conspicuous amphideal fovea which is not common to this genus (indistinct in Hypodontolaimus portuguese sp. n.).

Systematics (According De Ley et al. 2006)

Figures

FIGURE 2. Hypodontolaimus portuguese sp. n. holotype male: (A) anterior region (buccal cavity, cephalic setae, secretoryexcretory pore and pharynx posterior bulb), (B) reproductive system, (C) spicules, (D) posterior end (tail and spicules).

FIGURE 3. Hypodontolaimus portuguese sp. n. paratype female: (A) anterior region (buccal cavity, cephalic setae and pharynx posterior bulb), (B) reproductive system, (C) tail.

FIGURE 4. Hypodontolaimus portuguese sp. n. holotype male: (A) anterior end (cuticle), (B) tooth, (C) pharynx posterior bulb, (D) spicule, (E) tail.

FIGURE 5. Hypodontolaimus portuguese sp. n. paratype female: (A) anterior end (cuticle), (B) anterior end (tooth and pharynx posterior bulb), (C) tail region (arrowhead marks anus), (D) reproductive system (arrowhead marks vulva).