Pelmatodrilus
Pelmatodrilus Moore, 1943 (ref. ID; 5791)
ref. ID; 5791
Descriptions
External: Enchytraeids dorsoventrally flattened throughout body, with lateral membrane-like extension of epidermis extending from mouth to anus; extocommensal on earthworms. Prostomium and first segment anteroposteriorly compressd; mouth small, subterminal. Head pore at junction of prostomium and peristomium. Spermanthecal pores at 4/5 in line of dorsal setae. Setae slightly sigmoid, anodulate. Dorsal setae single or, rarely, paired, very small or lacking from some preanal segments, medial to membrane-like extension; tips recurved, pointed. Ventral setae multiple from most anterior segments, absent from XII (at least in mature specimens), fewest in most-posterior segments. Ventral setae with ectal tips in staggered anteriorly and posteriorly directed ranks, with ental ends in one rank; ectal tips somewhat spoon-shaped, thin, recurved. Setal bundles laterally paired. Clitellum extending over XII and XIII. Male pores ventrolateral in XII; female pores open in 12/13. Anus slightly recessed, just subterminal on ventral side. (ref. ID; 5791)
Internal: Brain truncate posteriorly. Dorsal blood vessel bifurcating ventral to brain; origin preclitellar. Pharyngeal glands compact. Spermathecae with glands at ectal pore; connected entally to esophagnus. Without peptonephridia, esophageal appendages, or other gut diverticula. Gut may have S-bend in VIII. Preseptal parts of nephridia including funnel only; efferent duct origins terminal. Testes paired in XI. Sperm contained in laterally paired, marginally lobed sperm sacs. Sperm funnels in XI, glandular, with eccentric canal. Penial apparatus elongate, with external muscular layer, with protrusile (?) ectal part extending into epidermal invagination. Without atria, prostates, or other copulatory glands. Ovaries paired in XII. Egg sacs not found. (ref. ID; 5791)
Remarks
No evidence of peptonephridia, or salivary glands, as described by Moore (1943), was found. Diagnostic enchytraeid characteristics of the reproductive systems were found, as discussed for Aspidodrilus. Apomorphies of Pelmatodrilus include, as for Aspidodrilus, overall body form and setal form and distribution. Spermathecae attached to the esophagus, as found in Pelmatodrilus, is a derived characteristic within the Enchytraeidae, and is diagnostic of a suprageneric monophyly. (ref. ID; 5791)
Type species (type by monotypy)
Pelmatodrilus planariformis Moore, 1943 (ref. ID; 5791)
- Pelmatodrilus planariformis Moore, 1943 (ref. ID; 5791)
Binomen; Pelmatodrilus planiformis Moore, 1943 (ref. ID; 5791)
- Pelmatodrilus planiformis Moore, 1943
See; Pelmatodrilus planariformis (ref. ID; 5791)
Binomen
Pelmatodrilus planiformis Moore, 1943 (ref. ID; 5791)
Descriptions
Description is based on material examined or, where data are given in brackets, on Moore 1943.
External: Mature whole-mounted specimens 7-9 [8.6] mm long, with 36, 37, 39 [41] segments. Width at IV-V about 1.3 [0.57] mm, at clitellum about 1.7 [1.25] mm; width about constant from clitellum to most-posterior segments. Marginal membrane thinner from VI[IV] posterior. Dorsal setal bundle beginning about 0.18 of body width from lateral body margin. Ventral setae 17-29 [maximum 30] per bundle, usually 25-30, slightly fewer in preclitellar segments, absent in XII, 17 or 18 in about XXX to most posterior segments, then only 6-9 setae per bundle. Setae about 75-100 µm long in postclitellar segments; ectal tips of ventral setae spoon-shaped. Replacement setae produced as complete bundles. (Some fully developed setae "free" in coelom of postclitellar segments). (ref. ID; 5791)
Internal: Pharyngeal glands with free dorsal lobes at 4/5 and 5/6, and very small at 6/7; small ventral lobes in IV and V. Spermathecal ectal duct surrounded at pore by about 10 large glands, ectal duct short and not very distinct; ampulla elongate with broad connection to esophagus at one-half V, no distinct ental duct; with sperm extending into esophageal lumen. Nephridia paired from 6/7, occurring in most postclitellar segments up to terminal 8 or 9. Dorsal blood vessel origin in VII or VIII. Gut twisted or flexed near 7/8. Inner intestinal wall highly folded in XIII-XVIII; posterior part of gut very straight. Clitellum extending over XII and XIII [XI-XIII], gland cells small, more or less regularly distributed. Seminal vesicle extending into X. Sperm funnel with somewhat irregular outline, 1.5-2 times as long as wide; collar subequal to funnel width. Vas deferens of more or less equal diameter throughout, about 20-22 µm, not highly muscularized, with canal diameter about 6-9 µm, 3 or more times as long as funnel, irregularly wound in XII. Penial apparatus elongate, about 400 µm, with a central "core" extending from the vas deferens in an elongate muscular sac, tip of core protruding into epidermal invagination; apparatus protrusile (?). With well-developed glandular lobes at ental end of apparatus. (ref. ID; 5791)
Remarks
Before referring to this species by the binomen Pelmatodrilus planiformis, Moore (1943) twice called it P. planariformis and later commented on its resemblance to planarians. It seems that P. planariformis rather than P. planiformis (Gelder, 1980) was the name that Moore intended and I designate it as the correct name in this first revision. There are no previously published illustrations of Pelmatodrilus, but the specimens I saw fit most of the characteristics described by Moore (1943), including geographical location. Nevertheless, some notable differences from his reported observations were found. In my investigations a head pore was found; pharyngeal peptonephridia were not observed; bulbous diverticula were not found on the gut; testes and ovaries were not obviously fused ventrally; and sperm sacs were present, although these may not be "true sperm vesicles" (Moore 1943). The general disregard of this species (Niesen and Christensen 1959; Kasprzak 1981) cannot be easily understood. Moore (1943) clearly was describing a highly derived enchytraeid, as similarities to Aspidodrilus, pointed out by Moore (1943) himself, indicated. (ref. ID; 5791)
Type locality
Elevation of about 1490 m (4900 ft), Morce's Gap, Blue Mountain Peak, Jamaica; epizoic on large earthworms (possibly two species, according to Moore 1943). (ref. ID; 5791)
Material examined
Material collected by R.P. Bengry, at first gully, Clydesdale, Morces's Gap (at or very near the type location) Jamaica, 26.VIII.1949, borrowed from JI, three specimens originally in alcohol, mounted and sectioned for this study. One slightly mature whole mount and one longitudinally sectioned specimen returned to JI; second mature whole mount, ROMIZ I1229. Type material could not be traced. (ref. ID; 5791)