Glyphanostomum Levinsen 1884

Glyphanostomum Levinsen, 1884

Type species: Samythella pallescens Théel, 1879

Generic diagnosis. Prostomium without glandular ridges. Buccal tentacles smooth. Three pairs of cirriform branchiae on one segment. Segment II without chaetae. Thorax with 14 chaetigers and 11 uncinigers. No modified segment. No abdominal rudimentary notopodia present.

Table 5: Synoptic table of characters of all species of the genus Anobothrus (Data taken from original descriptions, Jirkov (in press), and own observations. Abbreviations: C: chaetae, E: elevated notopodia, R: glandular ridge between notopodia, S: prolonged segments, TU: thoracic unciniger)

A. antarcticus A. apaleatus A. bimaculatus A. glandularis A. gracilis A. laubieri A. nasuta Monro, sp. nov. Fauchald, ( Hartmann- (Malmgren, (Desbruyères, (Ehlers, 1939 1972 Schröder, 1965) 1866) 1978) 1887)

Buccal papillose papillose smooth smooth smooth smooth smooth tentacles

Table 5: Synoptic table of characters of all species of the genus Anobothrus (continued) Table 6: Diagnostic characters of all genera with dorsal thoracic modifications (Abbrevations: AS: abdominal segments, NTP: notopodia, TC: thoracic chaetiger, TU: thoracic unciniger)

Table 6: Diagnostic characters of all genera with dorsal thoracic modifications (continued) Remarks to Table 6:

The Table lists all genera with dorsal modifications of certain segments. Besides information concerning modifications and their position, the most important diagnostic characters are given.

Some misinterpretations that have accumulated in literature are noted here. The erroneous data is due to non-uniform or incorrect terminology. Thus, there are confusions between segments, chaetigers, and uncinigers. Another problem lies in the fact whether segment II with chaetae formed as paleae are counted as chaetigers or not. In the section "Problems in the systematics of Ampharetidae ", suggestions are given to improve this situation.

1: Inconsistent data is given by Hartman (1965) in the original description of the monotypic genus Sosanella and its species Sosanella apalea Hartman, 1965. In the generic diagnosis she indicates three pairs of branchiae. A number which is also given by Fauchald (1977) and Holthe (1986a). In the species description, however, she describes in detail how the four (!) pairs of branchiae are arranged. To clarify this contradiction, type material must be examined. Because of the detailed description of the branchial arrangement, that reads: "Branchiae number four pairs; three pairs are inserted in a short, straight, slightly elevated row, leaving a wide medial space; the fourth pair is farther back, inserted above and behind the first notopodia", we consider a preliminary correction of the branchial number to four as appropriate.

2: In the original description of Ymerana pteropoda Holthe, 1986 the author traces the fan-shaped structure of the first abdominal segment back to modified notopodia without chaetae. He denies the presence of abdominal rudimentary notopodia, and considers this segment as a thoracic one. However, notopodial structures without chaetae are rudimentary per definition. Thus, there is one pair of abdominal rudimentary notopodia and the number of thoracic chaetigers ought to be 13 instead of 14.