Hydromermis
Hydromermis Corti, 1902 (ref. ID; 1770)
Family Mermithidae (ref. ID; 1770)
ref. ID; 1770
Diagnosis
Head generally not set off from body, cephalic papillae six, amphids generally large, situated at level of or posterior to level of cephalic papillae, mouth terminal or shifted slightly ventral. Vagina S shaped, vulval flap present, eggs small, many in uterus. Tail generally conoid tapering rapidly to pointed terminus. Male with one spicule, bulky, ranging from relatively short to very long. Genital papillae many, small to large. Tail conoid, tapering to acutely rounded terminus. (ref. ID; 1770)
Notes
Nickle (1972) assigned sharply pointed tailed adults from chironomids figured by Stiles (1892) and Hagmeier (1912) to this genus and placed the genus Paramermis in an uncertain position. In his diagnosis he included mermithids of which both sexes had pointed tail tips and the male has a single large spicule. (ref. ID; 1770)
Type species
Hydromermis contorta (von Linstow, 1889) Hagmeier, 1912 (ref. ID; 1770)
- Hydromermis churchillensis Welch, 1960 (ref. ID; 1770)
- Hydromermis conopophaga Poinar, 1968 (ref. ID; 1770)
- Hydromermis contorta (von Linstow, 1889) Hagmeier, 1912 (ref. ID; 1770)
- Hydromermis fluviatilis (Hagmeier) (ref. ID; 1770)
- Hydromermis illiesi n. sp. (ref. ID; 1760 original paper)
- Hydromermis itascensis Johnson (ref. ID; 1770)
- Hydromermis macrospiculatus Mulvey & Nickle, 1978 (ref. ID; 1770 original paper)
- Hydromermis palustris Hominick & Welch, 1971 (ref. ID; 1770)
Diagnosis
Welch (1960) described and illustrated this species. Adult paratype material was not available for study. The larvae were found by Welch in the larvae of Aedes communis (Deg.). Welch described "fused spicules" in the male (only two examined) which are probably the lateral longitudinal thickening Mulvey (1978) found in his male specimens. (ref. ID; 1770)
Descriptions
Parasitic in insects; from the haemocoele of mosquito larvae, Aedes communis (Deg.), from Goose Creek area, Churchill, Manitoba. (ref. ID; 1770)
Male: Head slightly expanded, rounded, mouth aperture terminal. Amphid aperture well posterior to level of cephalic papillae, walls of pouch fairly thick. Cuticle thin. Spicule bulky with thick walls and expanded head. Spicule shaft of uniform width to a bluntly rounded tip. Lateral longitudinal thickening present in walls of the spicule sometimes occupying three-quarters of the length of the spicule. Most of the spicules examined had these lateral thickenings. Tail conoid to abruptly tapering terminus. Genital papillae small, widely spaced. (ref. ID; 1770)
Female: Mouth terminal, amphid aperture posterior to level of cephalic papillae. Vulva with small flap, vagina S shaped. Tail conoid to acutely rounded terminus. (ref. ID; 1770)
Measurements
Male: Body length 14(10-17) mm; body width 91(80-120) µm; head width 45(40-50) µm; amphid aperture 5 µm; amphid pouch 8-10x12-13 µm; spicule length 227(170-280) µm; spicule head width 26(20-34) µm; spicule midshaft width 22(18-30) µm; tail length 301(240-380) µm; cuticle width 3-4 µm. (ref. ID; 1770)
Female: Body length 13.5(10-20) mm; midbody width 113(100-200) µm; head width 38(35-41) µm; amphid aperture 5.6 µm; amphid pouch 7-8x10 µm; eggs 42-50x35-42 µm, thickly packed in several rows; cuticle width 6-10 µm. (ref. ID; 1770)
Diagnosis
This descriptions (Mulvey 1978) fit Poinar's description (1968). However, Poinar did not mention any of has specimens having spicule with longitudinal thickening which are present in at least half of the specimens Mulvey examined. Poinar stated that the spicles of his males had minute granulation on the distal tips. Mulvey specimens all had distal tips provided with a hyaline are containing some granules. Hominick and Welch (1971) described male specimens of this species from Manitova in which the spicule tip was either flat or with three small projections. The position of the amphidial opening of the Mackenzie specimens conforms very closely to that illustrate by Poinar. (ref. ID; 1770)
Descriptions
Parasitic in insects; from the haemocoele of chironomid larvae from Portage Creek in the Delta Marsh, Manitoba. (ref. ID; 1770)
Male: Head rounded, mouth opening ventrally shifted. Amphid aperture well posterior to level of cephalic papillae. Spicule head flared, spicule with or without longitudinal thickenings. Spicule shaft with thick walls of uniform width to bluntly rounded terminus. Genital papillae numerous, evenly and closely spaced. Tail conoid, bulky to acutely rounded tip. Cuticle thin. (ref. ID; 1770)
Female: Not found. (ref. ID; 1770)
Measurements
Male: Body length 5.4(4.0-8.0) mm; body width 98(65-110) µm; head width 39(30-45) µm; amphid aperture width 6-7 µm; amphid pouch 8-9x10-12 µm; spicule length 154(140-175) µm; spicule head width 24(20-30) µm; spicule midshaft width 16(13-20) µm; tail length 195(160-240) µm; cuticle width 3-4 µm. (ref. ID; 1770)
Hydromermis contorta (von Linstow, 1889) Hagmeier, 1912 (ref. ID; 1770)
Descriptions
Parasitizing chironomids in the Marion Lake area of British Colymbia and identified by Dr. W.R. Nickle. (ref. ID; 1770)
Diagnosis
Hydromermis macrospiculatus n. sp. differs from H. churchillensis in spicular size and length (370-560 vs. 170-280 µm) tail length (average 460 µm vs. 301 µm for H. churchillensis) and in having massive genital papillae. Welch (1960) mentioned the presence of paired spicules fused for one-half their length in describing the male of H. churchillensis. This observation was based on one whole male and the posterior part of a second; neither was available for examination. The conditions of the spicule described by Welch probably represents the lateral longitudinal thickenings of the spicule found in many males of H. churchillensis, H. macrospiculatus, and H. conopophaga which we examined. When the spicule is within the thickenings are very distinct but when the spicule is removed from the body these thickenings nearly disappear. Therefore, it appears that the infolding of the spicular wall has caused these thickenings and gives the effect of fused spicules. The constancy of these lateral thickenings of the spicule is a good species character. The genital papillae are very large and thick in H. macrospiculatus and consist of three distinct areas, viz. an inner canal (duct) extending (leading) inwards, a small circular lip area, and an outer wide circular ring. The size, spacing and position of genital papillae are of use in species identification. Punctations (sensillae) on the spicule tip are distinct and numerous on the terminal area of the spicule of H. marcospiculatus and are probably sensory in function. (ref. ID; 1770)
Descriptions
Male: Head angular amphid aperture posterior to level of cephalic papillae, walls of pouch thick, mouth terminal. Spicule massive (380-560 µm), shaft of uniform thickness, walls thick, head slightly flared, spicule terminus rounded, provided with many small punctations. Lateral longitudinal thickenings present in spicule of all males examined and extending nearly the entire length of each spicule. Genital papillae large, closely spaced. Tail conoid arcuate with pointed terminus. Genital papillae extending nearly to tip of tail. Cuticle relatively thin. (ref. ID; 1770)
Female: Not found. (ref. ID; 1770)
Measurements
Male: Body length 22.0 mm; midbody width 180 µm; head width 60 µm; amphid aperture 6 µm; amphid pouch 12x17 µm; spicule length 380 µm; spicule head width 38 µm; spicule midshaft width 36 µm; tail length 520 µm; cuticle at midbody 6 µm. (ref. ID; 1770)
Descriptions
Parasitic in insects; from the haemocoele of chironomid larvae from Portage Creek in the Delta Marsh, Manitoba. (ref. ID; 1770)