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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Phreodrilus

Phreodrilus Beddard, 1891 (ref. ID; 7264) or 1981 (ref. ID; 6563, 6913)

Family Phreodrilidae: Subfamily Phreodrilinae (ref. ID; 6563)

ref. ID; 6563

Phreodilinae with eversible penes. (ref. ID; 6563)

Type species

Phreodrilus subterraneus Beddard, 1891 (ref. ID; 6563)
  1. Phreodrilus beddardi Benham, 1904 (ref. ID; 6563)
  2. Phreodrilus branchiatus Beddard, 1894 (ref. ID; 6563)
  3. Phreodrilus campbellianus (ref. ID; 7254)
  4. Phreodrilus crozetensis Michaelsen, 1905 (ref. ID; 6563, 6913)
  5. Phreodrilus kerguelenensis Michaelsen, 1903 (ref. ID; 6563)
  6. Phreodrilus lacustris Benham, 1903 (ref. ID; 6563), Phreodrilus (Insulodrilus) lacustris Benham, 1903 (ref. ID; 7254)
    See; Insulodrilus (ref. ID; 6563)
  7. Phreodrilus litoralis (ref. ID; 7254)
  8. Phreodrilus mauienensis Brinkhurst, 1971 (ref. ID; 6563)
  9. Phreodrilus niger (Beddard, 1894) (ref. ID; 6913)
  10. Phreodrilus notabilis (Benham, 1907) (ref. ID; 6563)
  11. Phreodrilus nudus Brinkhurst & Fulton, 1979 (ref. ID; 6563)
  12. Phreodrilus palustris Brinkhurst & Fulton, 1979 (ref. ID; 6563)
  13. Phreodrilus uniseta Brinkhurst, 1982 (ref. ID; 6563)

Phreodrilus crozetensis Michaelsen, 1905 (ref. ID; 6563, 6913)

Descriptions

The sections prepared for an earlier review (Brinkhurst 1965) were reexamined. There is no sign of any spermathecal chaetae. The very simple penes. One male duct opens onto the posterior wall of a simple sac, as described by Michaelsen (1905). The opposite duct ends in a small penis formed by slight folding of the body wall. The short vasa deferentia enter the atria basally, as originally described. (The external view of the male pore in P. kerguelenensis can probably be interpreted as being derived from a very similar structure.) The sperm sac occupies VII-XI. The sperm in the spermathecae are bundled. The pharyngeal roof is thick and glandular but there are no large sets of retractor muscles attached to it dorsally. This is in contrast to the original description, which gives the impression that the pharyngeal roof is as well developed as in the enchytraeids. The whole-mounted specimen from the Stockholm collection (247, South Georgia) has paired simple-pointed ventral chaetae. One is blunter than the other but no rudimenty upper teeth were visible on the fewunbroken chaetae. The ventral chaetae progressively enlarge posteriad. There are ordinary ventral chaetae in XIII (where the modified spermathecal chaetae would be found if they were present). The dorsal chaetae consist of one or two hair chaetae with lateral chaetae. The specimen is mature, with sperm in segments VII-XI and eggs in XII-XIII. There is a thickening of the posterior wall of the chamber lying within the male pore which presumably forms a small conical penis. There are no septal glands but the pharyngeal roof is thick and glandular. (ref. ID; 6563)

Type material

Naturhistoriska Riksmuseet, Stockholm, Swedish South Polar Expedition, 1901-1903, and Swedish Antarctic (Magellan) Expedition, 1907-1909. Phreodrilus crozetensis as follows: 247 Cumberland Bay, South Georgia, 18 May 1902. "Am Boden einem Binnensees bei Moraufjorden." 7 pieces, some mature. 1 as a stained permanent whole mount of a mature specimen, the others examined in fluid. 270 Lago Fagnano, South Tierra del Fuego, 1907-1909, March 21 (year unknown). 31 m. 2 heads, 4 tails, 1 whole mature animal in spirit, 1 specimen as longitudinal sections (made by the author in Liverpool, England). 373 South Georgia, Trytviken, 11 June 1902. 20 m. Phreodrilus ?crozetensis. (ref. ID; 6563)

Phreodrilus kerguelenensis Michaelsen, 1903 (ref. ID; 6563)

Descriptions

The BANZARE specimens from Kerguelen Island where examined. The dried specimens (E1855) have single (often broken) hair chaetae dorsally, each broad basally but tapering quite abruptly towards the tip. Each is accompanied by a pair of shorter chaetae. The ventral chaetae are curved, thin, and simple-pointed or rudimentarily bifid. As many of them are broken, it is impossible to determine any regular pattern of bifid versus simple-pointed, but some bundles do seem to have both chaetae of the last form. The ventral chaetae become progressively enlarged posteriad in the first 13 segments. The genital region in all specimens was distored by shrinkage, and deep folds possibly created by this could be confused with the apparent male pores. Two specimens seems to have spermathecal chaetae, but it was impossible to clear the specimen enough to be certain. The genital region is deeply folded midventrally in all three whole-mounted specimens, forming a groove from XIII-XIV or XV. The male pore is crescentic in form, the posterior edge having what may be, in three dimensions, a spherical swelling which appears to resemble the rudimentary penis of Phreodrilus crozetensis. The collection E1856 has not been dried, and two whole mounts were made. One specimen proved to be an enchytraeid, the other a mature phreodrilid with obvious spermathecal chaetae. The original label (written by L. Cernosvitov) shows the tentative identification ?kerguelensis. The stained whole-mounted specimen has spermathecal chaetae and these are situated medial to the normal ventral chaetal line, as in kerguelenensis. The dorsal chaetae in this specimen are paired hairs, each with small lateral chaetae. The ventral chaetae of each pair differ slightly in width and curvature ectally, suggesting the usual phreodrilid pattern of one simple-pointed and one rudimentarily bifid chaeta. The sperm sac occupies VII-XI. The genital region was dissected after the initial examination was completed, in an attempt to confirm the claim that the vasa deferentia enter the atria medially rather than at the usual ectal location. The attempt was not successful; it was impossible to confirm that the male and spermathecal pores are median. The syntype specimen from Wroclaw had been dried, and was soaked in detergent and glycerol in alcohol. No additional information was derived from examination of this specimen. (ref. ID; 6563)

Type material

South Australia Museum, Adelaide. British-Australian-New Zealand Antarctic Research Expedition, 1929-1931 (BANZARE) collection. Material examined by L. Cernosvitov as reported by Lee (1968). Phreodrilus (as Hesperodrilus) kerguelenensis as follows: E1855 TE9908, Observatory Bay, Kerguelen Island, 19 February 1930. In soft mud of tarn. 15 specimens, dried, 3 whole mounts prepared. E1856 TE9909 same location, labelled ?kerguelenensis. A mixture of unnamed enchytraeids and 1 whole mounted mature phreodrilid. (ref. ID; 6563)

Phreodrilus lacustris Benham, 1903 (ref. ID; 6563), Phreodrilus (Insulodrilus) lacustris Benham, 1903 (ref. ID; 7254)

See

Insulodrilus (ref. ID; 6563)

Descriptions

The dorsal chaetae in this material begin in III, and consist of 1 (2) hairs and 2 (4) short, rarely hair-like, usually broken chaetae on each side of each hair, which appear to be related to the hair. Evidence for this comes from the situations in which the main hair has dropped out leaving the two lateral structures in place, making it seem as though they are supports for the hair. Scanning electron microscope studies are needed to clarify the nature of these structures, which do not usually extend beyond the body wall. The ventral setae are paired, of similar width and length, nodular and rudimentarily bifid or sometimes simple-pointed. The modified spermathecal chaetae in XII are hollow-ended and may be single or with a smaller (developing replacement?) chaeta beside them. The spermathecal pores are ventral, and appear to bear vestibulae. Large true penes are present. (ref. ID; 7254)

Remarks

The species in this small family are contained within a single genus until relationships become clearer, but several subgenera are used to recognize phenotypically similar groups of species. Insulodrilus includes those with true penes, ventrolateral spermathecal pores usually with vestibulae at the pores, and spermathecal chaetae. Several have characteristic chaetae, but among those with simple, narrow hair chaetae dorsally are P. lacustris, which has only a rudimentary spermathecal vestibule, Phreodrilus campbellianus (no spermathecal chaetae, distinctly different paired ventrals), and Phreodrilus litoralis (with spermathecal chaetae). (ref. ID; 7254)

Material examined

Mascardi Lake, Rio Negro Province, Argentina, 1968-1969, coll. I.E. de Drago and D.H. Di Persia, 6 mature specimens (USNM102751). (ref. ID; 7254)

Phreodrilus notabilis (Benham, 1907) (ref. ID; 6563)

Descriptions

The type and only specimen has hair chaetae without lateral chaetae, according to P. Hutchings, who examined the specimen at the author's request. (ref. ID; 6563)

Type material

Holotype: 5606-9, examined by P. Hutchings to confirm type of dorsal chaetae. The Australian Museum, Sidney, Australia. (ref. ID; 6563)

Phreodrilus nudus Brinkhurst & Fulton, 1979 (ref. ID; 6563)

Descriptions

A specimen from the type series in the Brinkhurst collection has small support chaetae on either side of the single hair chaeta of each "bundle." This has not been reported previously. (ref. ID; 6563)

Type locality

South Esk River, Tasmania. (ref. ID; 6563)

Phreodrilus uniseta Brinkhurst, 1982 (ref. ID; 6563)

Descriptions

No specimens were examined, but a correction to the original description should be noted. In the original published description a line of text dealing with the chaetae was omitted. The dorsal chaetae begin in III, IV, or V and are single, sigmoid, and simple-pointed and resemble the ventral chaetae. The ventral chaetae are paired, one being simple-pointed and the other bifid. (ref. ID; 6563)