Macrolaimus inecolensis

Body an open C shape, curved ventrad after fixation; Cuticle with very fine striations. Head truncate, continuous with the body contour 10.0 - 12 (11.0 ï¿½ 1.2) μm wide. Stoma surrounded by six triangular-shaped lips that are not fused; inner labial sensilla not visible, six conoid outer labial setae 2.0 μm long, and four small cephalic sensilla situated slightly posterior to the outer labial setae. Amphid apertures small, oval shape, located two cuticular striations posterior to the cephalic setae at 3.0 - 6.0 (4.8 ï¿½ 1.3) μm from the anterior end. Stoma heavily sclerotized, subdivided into cheilostom 5.0 - 6.0 (5.7 ï¿½ 0.5) μm long and gymnostom 2.0 - 3.0 (2.7 ï¿½ 0.5) μm long; cheilostom/gymnostom 1.4 - 2.5 (1.9 ï¿½ 0.5) times longer than gymnostom; the stegostom is funnel-shaped but not clearly visible. Lateral field with two fine incisures. Esophagus cephaloboid: corpus cylindrical 97.0 - 106.0 (101.0 ï¿½ 4.6) μm long and 1.8 - 2.1 (1.9 ï¿½ 0.2) times longer than the isthmus; isthmus narrower 50.0 - 55.0 (52.0 ï¿½ 2.2) μm long; metacorpus nearly pyriform, 16.0 - 23.0 (20.8 ï¿½ 3.2) μm long and 15.0 - 28.0 (19.5 ï¿½ 5.8) μm wide. Cardia conoid. Nerve ring in the first third of the isthmus at 111.0 - 131.0 (119.5 ï¿½ 8.7) μm from the anterior end. Excretory pore posterior to the nerve ring and anterior to the deirid at 155.0 - 132.0 (125.0 ï¿½ 7.3) μm from the anterior end. Deirid difficult to see. Anterior region of Macrolaimus montrealensis (from Cid del Prado et al., 2020) Female: Reproductive system monodelphic-prodelphic with the ovary reflexed, the germinal area at 53 - 130 μm from the anus, with a postuterine sac, 12.0 - 20.0 (17.2 ï¿½ 3.6) μm long. Vulva with protruding lips oriented posteriad, anterior lip the larger, the vulva is 471.3-555.0 (518.8 ï¿½ 34.9) μm from the anterior end. Two gland cells, 5 μm long by 3 μm wide with conspicuous nuclei, are located one anterior and the other posterior to the vagina. Vagina length 7.0 - 10.0 (8.3 ï¿½ 1.5) μm. Rectum 20 - 28 (22.8) 3.8) μm long length and 1.3 - 2.3 (1.6 ï¿½ 0.3) times anal body diameter with two gland-like cells at its anterior end. Tail elongate conoid, curved ventrally and ending in an acute tip with a dorsally-curved mucro, and 4.8 - 5.9% (5.4 ï¿½ 0.5) of the body length. Anal lips slightly protruding, mainly the posterior lip. Phasmids located in the posterior end of the tail 27.0 - 34.0 (31.0 ï¿½ 3.1) μm from the anus and 57.4 - 66.0% (62.6 ï¿½ 4.0) of tail length. Male: Reprodictive ssystem monorchic reflexed ventrad. Spicules paired and symetrical, curved ventrad, 22 μm long; manubrium with rounded proximal end, short calamus and curved lamina. Gubernaculum arc-shaped 10.0 ï¿½ 11.0 (10.7 ï¿½ 0.6) μm long Three gland-like cells are present anterior to the spicules. Three pairs of subventral precloacal genital papillae; one pair is 4.0 - 5.0 (4.73 ï¿½ 0.6) μm and the second 16.0 - 25.0 (21.0 ï¿½ 4.6) μm and the third 30.0 ï¿½ 45.0 μm from cloacal aperture. Five postcloacal pairs of papillae. Phasmids are located in the posterior half of the tail at 16.0 - 29.0 (23.3 ï¿½ 6.7) μm from the anus. Tail curved more ventrad than in females, 28.0 - 36.0 (33.0 ï¿½ 4.4) μm long ending in an acute tip with a dorsally-curved mucro. Characteristics from Cid del Prado-Vera et al. 2020.


Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

Distribution:

Macrolaimus inecolensis was collected on February 20, 2020, from a filamentous epiphyte, Misodendrum sp. (Misodendraceae) growing on a tree in the Botanical Garden of the Ecology Institute of Jalapa, Veracruz, Mï¿½xico, N 19ï¿½30'47.4", W 96ï¿½56'32.9ï¿½, elevation 1400 m asl.

Feeding:

Macrolaimus spp. are assumed to be bacterivores based on the unarmed stoma and the cephaloboid oesophagus. Given their frequent association with insects, besides the advantage of transportation to new resources by phoresy, some species may acquire resources through necromeny, that is, by feeding on bacteria that are exploiting the bodies of dead insects.

Biology and Ecology:

Like Macrolaimus inecolensis, some species of the genus have been described from above-ground habiats associated with lichen, moss and insect galleries in tree trunks (Thorne, 1937; Sanwal, 1960) while others have been described from soil samples (Abolafia et al., 2019; Swart and Heyns, 1992; Timm, 1960; Andrassy, 1984).

Species of Macrolaimus may be carried among above-ground habitats by insects (Massey, 1974).

Azizoglu et al. (2016) noted that Macrolaimus species are commonly recovered from bark infested with beetles; M. canadensis was isolated from the frass of the bark beetle Phloeosinus canadensis (Sanwal, 1960), M. crucis was isolated from the pine - top weevil gallery Pissodes piniphilus (Poinar, 1975), and M. taurus, was isolated from gallery of Ips confusus on Pinus edulis (Thorne, 1937).

Life Cycle:

Ecosystem Functions and Services:

Management:

References:

Abolafia, J., A. N. Ruiz-Cuenca, J. Foit, and V. Čermak. 2019. Redescription of Macrolaimus canadensis Sanwal, 1960 and M. ruehmi Andrï¿½ssy, 1966 (Nematoda, Rhabditida, Chambersiellidae), and new data on M. crucis Maupas, 1900. Journal of Helminthology 93:109-125.

Andrï¿½ssy, I. 1984. Klasse Nematoda (Ordnungen Monhysterida, Desmocolecida, Araeolaimida, Chromadorida, Rhabditida) Bestimmungsbűcher zur Bodenfauna Europas, No.9. Berlin (Deutschland): Akademie Verlag.

Azizoglu, U., S. Karaborklu, A. Ayvaz, and S. Yilmaz. 2016. Phylogenetic relationships of insect-associated free-living rhabditid nematodes from eastern Mediterranean region of Turkey. Applied Ecology and Environmental Research 14:93-103.

Cid del Prado-Vera, I. Ferris, H., Subbotin, S.A. 2020. Two new species of Macrolaimus (Nematoda: Chambersiellidae) with comments on diagnostic characters for distinguishing species. Nematropica 50:170-185.

Massey, C. L. 1974. Biology and taxonomy of nematode parasites and associates of bark beetles in the United States. Agriculture Handbook no. 446. Washington: USDA Forest Service.

Maupas, E. F. 1900. Modes et formes de reproduction des nï¿½matodes. Archives de Zoologie Experimentale et Gï¿½nï¿½rale 8:463-624.

Poinar, G. O. 1975. Entomogenous nematodes: A manual and host list of insect-nematode associations. Leiden, The Netherleands: Brill.

Sanwal, K. C. 1960. Macrolaimus canadensis n. sp. (Nematoda: Panagrolaiminae), from the frass of the bark beetle Phloeosinus canadensis Swaine, 1917, with remarks on other species of the genus Macrolaimus Maupas, 1900. Canadian Journal of Zoology 38:1127-1131.

Swart, A., and J. Heyns. 1992. Macrolaimus richteri spec. nov. (Nematoda: Chambersiellidae) from the Richtersveld, South Africa. Koedoe 35:19-23.

Thorne, G. 1937. A revision of the nematode family Cephalobidae Chitwood and Chitwood, 1934. Proceedings of the Helminthological Society of Washington 4:1-16.

Timm, R.W. 1960. Brevibucca punctata, n.sp. and Macrolaimus natator, n.sp., new soil nematodes from East Pakistan. Biologia 6:252-256