Mononchus truncatus Bastian 1865
- Dataset
- Integrative taxonomic study of mononchid nematodes from riparian habitats in Bulgaria. I. Genera Mononchus Bastian, 1865 and Coomansus Jairajpuri & Khan, 1977 with the description of Mononchus pseudoaquaticus sp. nov. and a key to the species of Mononchus
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Nematoda
- class
- Enoplea
- order
- Mononchida
- family
- Mononchidae
- genus
- Mononchus
- species
- Mononchus truncatus
description
Description. Female [Based on 14 specimens from 6 localities; see Table 4 for measurements.] Body of most specimens straight, with only last part of tail ventrally curved (body C-shaped upon fixation in a few specimens), comparatively slender, body diameter at mid-body 53 – 71. Cuticle smooth under light microscope, 2 – 3 thick along most of body, thicker (4 – 5) in post-anal region. Lip region rounded, continuous with adjoining body, papillae small, cephalic papillae very small and rounded, labial papillae somewhat larger and conical. Body at posterior end of pharynx 1.2 – 1.4 times as wide as body width at lip region. Amphids with oval apertures, situated at the beginning or middle of buccal capsule, at 11 ± 1 (10 – 13) (n = 12) from anterior end and 40 ± 3 (37 – 44) (n = 12) from posterior end of buccal capsule, aperture 4.5 ± 0.5 (4 – 5) (n = 12) wide. Buccal capsule oval, tapering at base, 2.0 – 2.3 as long as wide or 1.3 – 1.7 times as long as lip region width; its ventral wall 2 – 3 thick, dorsal wall posterior to dorsal tooth ~ 3 – 5 thick. Dorsal tooth strong, its anterior margin 5 ± 0.6 (4 – 6) (n = 12) wide, located at 11 ± 0.5 (10 – 12) from anterior end of buccal capsule. Ventral wall with short, not so well visible rib, ventro-sublateral transverse ribs located at level of tooth apex or slightly more anterior. Nerve-ring at 127 ± 8 (116 – 144) (n = 12) from anterior end of body. Excretory pore weakly marked, posterior to nerve-ring. Reproductive system amphidelphic. Anterior genital branch 193 ± 14 (175 – 223) long, posterior branch somewhat longer, 204 ± 16 (187 – 240) long. Ovaries well developed, not reaching uterus-oviduct junction; anterior ovary 107 ± 17 (75 – 142) (n = 12) long, posterior ovary 114 ± 18 (95 – 146) (n = 12) long. Oviduct with marked pars dilatata oviductus, 33 ± 7 (20 – 45) wide. Uteri thick-walled tubes, 40 – 60 long, length ranges for anterior and posterior uterus almost identical. Vagina with straight walls, 28 ± 3 in length representing 24 – 33 % of corresponding body width; pars refringens vaginae as two rounded drop-shaped pieces with smooth surface, 3 – 5 long and 2 – 3 wide. Vulva transverse, not protruding. Vulva-anus distance equals 2.3 – 3.3 tail lengths. Tail long, slender, curved ventrally in second part, length representing 11 – 13 % of total body length, 11 – 13 µm wide at cylindrical part, with rounded and slightly swollen tip. Caudal glands moderately developed, arranged in group, spinneret terminal. Male. Not found.
description
Figs 8, 9
distribution
Distribution. According to the abundant published data for materials reported as M. truncatus, this species appears to exhibit a worldwide distribution. However, we agree with Andrássy (2011 a) who doubted that all of the records referring to M. truncatus concern in fact this species. In Bulgaria, M. truncatus has been reported from many localities but with no morphological evidence supporting identification. Andrássy (1958) recorded this species for the first time in Rila Mountains and Varna. Subsequently, M. truncatus was reported from the North Thracian Plain (Katalan-Gateva 1962) and Pazardzhik Province (Katalan-Gateva 1965) associated with cultivated plants. In aquatic habitats, the species has been reported in sediments from 24 rivers and three lakes (Stoichev 1996; Stoichev and Chernev 2011; Stoichev and Varadinova 2011). The present study is the first to provide morphological and morphometric data for M. truncatus in Bulgaria.
Name
- Homonyms
- Mononchus truncatus Bastian 1865