Laevides ingens, Andrássy, 2010

Andrássy, I., 2010, Two New Species Of Dorylaimida (Nematoda) From The Mediterranean Region, Acta Zoologica Academiae Scientiarum Hungaricae 56 (3), pp. 201-210 : 202-206

Laevides ingens sp. n.

( Figs 1 A–D , 2 A–B and 3 A–F)

Holotype female. L = 5.46 mm; a = 52; b = 6.5; c = 98; c’ = 1.0; V = 47%.

Paratype females (n = 6). L = 5.44–6.45 mm; a = 57–64; b = 6.3–6.9; c = 92–104; c’ = 0.9–1.3; V = 46–51%.

Paratype male. L = 5.16 mm; a = 64; b = 5.7; c = 74; c’ = 1.3.

Type specimens. Holotype female on slide No. 12449. Paratypes: six females and one male. Type specimens will be deposited at the Hungarian Natural History Museum.

Type habitat and locality. Mud from a small lake in Buteicha Valley, part of the Jordan Great Rift Valley at north-eastern corner of Lake Kinneret (= Sea of Galilee or Gennesaret), between Galilee and Golan Heights, Israel; collected in February, 1984 by F. D. POR (Jerusalem).

General description. Body very large and slender, straight when relaxed, equal in thickness with exception of extremities; width 92–110 µm (female) or 80 µm (male) wide at mid-length. Cuticle smooth, relatively thin, thickness 3.0–3.5 µm on most body and 5–7 µm on tail. Lip region 22–24 µm wide, not differentiated, practically confluent with neck (or very slightly offset); lips amalgamated with minute papillae. Body at posterior end of oesophagus 4.2–4.5 times as wide as head. Amphid apertures occupying about half of corresponding body width. Mouth tube 52–57 µm long (measured from oral field), spacious.

Mural tooth small and thin, 14–16 µm long on the dorsal sector, dorylaimoid with a short oblique dorsal aperture. Entire length of tooth about equal to two-thirds the width of lip region. Oesophagus 830–920 µm long, comparatively short, occupying less than one-sixth of total body length, gradually widened at middle. Oesophageal gland nuclei rather inconspicuous; D = 62–66%, AS 1 = 23–26%, AS 2 = 26–28%, PS1 = 68–70%, PS2 = 69–72%. Glandularium 250–280 µm long. Cardia with three large spherical glands.

Female. Genital apparatus amphidelphic, well developed, each branch 6.0–6.7 times the body width long or occupying 12–13% of body length (if no uterine eggs present), and 9.6–10.0 times the body width long or occupying 15–16% of body length (if uterine eggs present). Vulva transverse, its lips not sclerotized, vagina narrow, yellowish in colour, 40–42 µm long, extending over 40% of body width. Eggs 2–4 in number, very large, oblong, measuring 220–330 µm by 70–75 µm, 2.4–3.4 times as long as mid-body width. Distance between posterior end of oesophagus and vulva 2.0–2.2 times as long as oesophagus. Vulva–anus distance equal to 40–54 tail lengths. Prerectum long and slim, 4.6–6.0 times longer than anal body diameter. Tail 52–75 µm long, or 1.0–1.3% of entire length of body, as long as or somewhat longer than anal body diameter, slightly clavate, with broadly rounded terminus.

Male. Similar to female in most characters. Testes two, spermatozoa fusiform. Spicula 100 µm long along the curved axis. Gubernaculum 17 µm long. Ventromedial supplements 6, well spaced. Prerectum 7.6 anal body widths long, beginning anterior to supplements. Tail 70 µm long, broadly rounded. Caudal papillae three pairs.

Main characters and relationships. A very large and slender species with head practically not offset, small and slender buccal tooth, long prerectum, simple vagina, long gonads, long eggs, slender spicula, widely spaced ventromedial supplements and broadly rounded, somewhat clavate tail.

The genus Laevides HEYNS, 1968 belongs to the family Nygolaimidae , and, including the new one, contains fourteen species. They live in both terrestrial and limnetic habitats, and are distributed in Europe, Asia, Africa, North and South America. This genus contains the longest specimens among the nygolaimoid nematodes. While the body of the major part is ranging between 1.3 and 3.3 mm, three species may reach 4 or even 7 millimetres. These latter are Laevides rapax ( THORNE, 1939) HEYNS, 1968 , L. husmanni ( MEYL, 1954) HEYNS, 1968 and L. loofi HEYNS, 1968 . It should be noted that L. husmanni and L. loofi are very likely identical with each other.

In its body size, Laevides ingens sp. n. can be compared with the above mentioned large species. It differs from L. rapax by the longer body (females 5.4–6.4 vs. 3.7–4.5 mm), wider head (22–24 vs. 18–19 µm), thin tooth, shorter oesophagus

Fig, 3. Laevides ingens sp. n. microphotos: A–B = anterior end, C–D = vulval region, E–F = female posterior end

(b = 6.3–6.9 vs. 4.5–5.5), and by the simple and narrow vagina. It can be differentiated from L. husmanni and L. loofi by the not so extremely long body (females 5.4–6.4 vs. 6.0– 7.3 mm), shorter buccal tube (52–57 vs. 65–66 µm), thinner tooth, more posteriorly located vulva (46–51 vs. 39–42%), and by the shape of the vagina.

Etymology. The species epithet ingens (Latin) means: huge, very big.

Figures

Fig. 1. Laevides ingens sp. n.: A = anterior end, B = cardial region, C = vulval region (intestine with compact contents), D = uterine egg. (Scale bars 20 µm each)

Fig. 2.Laevides ingens sp.n.:A =female posterior region, B= male posterior region.(Scale bar 20 µm)