The subfamily Maldaninae Arwidsson is revised and the species previously assigned to the genus
Asychis [
sensu lato] are reviewed.
Asychis is restricted to forms lacking a collar on setiger 1 and bearing U-shaped nuchal organs, only 1 preanal asetiger and a well developed pygidium with cirri.
Sabaco Kinberg is resurrected and includes
Maldanopsis Verrill and
Branchioasychis Monro.
Chirimia new name, is a replacement name for
Chrysothemis Kinberg, which must be rejected for reasons of homonymy, and Kinberg's concept of that genus is resurrected.
Metasychis, new genus, is proposed to include several widespread forms which are intermediate between
Chirimia and
Sabaco.
Asychis Gray [Porifera] is a junior homonym of
Asychis Kinberg.
Chirimia includes:
C. amoena (Kinberg),
C. biceps (Sars),
C. similis (Moore),
C. punctata (Zachs) and
C. fauchaldi, new species.
Maldane brasiliensis Kinberg is synonymized with
C. amoena, and
Maldane lacera Moore and
Asychis lobata Fauchald are synonymized as
Chirimia biceps lacera.
Asychis [
sensu stricto] includes:
A. atlanticus Kinberg,
A. amphiglyptus (Ehlers),
A. trifilosus Augener,
A. auritus Uschakov,
A. ramosus Levenstein and
A. chilensis (Hartmann-Schröder).
Metasychis includes:
M. disparidentatus (Moore),
M. gotoi (Izuka) and
M. fimbriatus (Treadwell).
Maldane coronata Moore,
Maldane collariceps Augener and
Asychis shaccotanus Uchida are all considered synonyms of
Metasychis gotoi.
Sabaco includes:
S. maculatus Kinberg,
S. elongatus (Verrill),
S, carolinae (Day),
S. atlantideus (Kirkegaard),
S. dorsofilis (Kirkegaard),
S. dakarensis (Rullier),
S. javanicus (Augener),
S. gangeticus (Fauvel),
S. steineri new species and
Asychis sp. of Augener (1918).
Important generic-level characters include the configuration of the prostomial palpode and nuchal organs, the type of notosetae, the presence or absence of the anal valve or of a collar on setiger 1, the number of preanal asetigers and the development of the pygidium. There are three types of notosetae: (1) anterior, simple capillaries, (2) , spirally fringed notosetae, and (3) simple companion setae with long whiplike tips accompanying the spirally fringed forms. The spirally fringed notosetae are classified into 3 types: (1) Type A, the most primitive form, with spinose spiral bands closely imbricated over the main shaft, (2) Type B, found only in the genera
Sabaco and
Metasychis, with delicate spiral bands expanded away from the main shaft, and (3) Type C, found only in
Chirimia punctata, with very delicate, cilialike fimbriae arising from greatly elongated nodes on the main shaft. The companion setae are either short, the whiplike tips not reaching the bases of the distal fimbriae, or long, reaching almost to or well beyond the tips of the spirally fringed notosetae. The short condition is primitive and always found with notosetae of Types A and C; long companion setae are always associated with Type B notosetae.