Manayunkia Leidy, 1859

Bick, Andreas, Oberrisser, Philipp & Bastrop, Ralf, 2024, Redescription of Manayunkia caspica Annenkova, 1929 and M. danubialis Băcescu, 1944 n. comb. (Fabriciidae, Sabellida, Polychaeta), Zootaxa 5477 (4), pp. 445-464 : 448

Manayunkia Leidy, 1859

Dybowscella Nusbaum, 1901 , subjective synonymy

Fabricia (Manayunkia) Southern, 1921 , superseded original combination

Garjaiewella Dybowski, 1929 , subjective synonymy

Haplobranchus Bourne, 1883 , objective synonymy

Trichosobranchella Dybowski, 1929 , subjective synonymy

Type species: Manayunkia speciosa Leidy, 1859 , by monotypy.

Diagnosis. (after Bick 2020, emended). Eight thoracic and three abdominal chaetigers. Pectinated radioles present, i.e., radioles asymmetrically branched; acellular supporting tissue almost completely absent. Unbranched vascularized ventral filamentous appendages present. Dorsal lips erect, broadly rounded. Branchial heart dorsally in the peristomium. Anterior margin of anterior peristomial ring developed as a membranous collar with rectangular or rounded ventral lobe, narrowly separated mid-dorsally; ciliary band between anterior and posterior peristomial ring ventrally. Inferior thoracic notochaetae short, narrowly hooded or pseudo-spatulate; thoracic uncini with rows of equal-sized or progressively smaller teeth above main fang; sexual dimorphism present: transitional chaetae or transitional uncini in chaetigers 6–8 usually present in females, and brood chamber may be also present in females; dentate region of abdominal uncini with multiple rows of equal-sized teeth; manubrium distinctly longer than dentate region. Peristomial eyes present, pygidial eyes absent. Spermiogenesis in chaetigers 6–8.

Remarks. Most species of Fabriciidae have an acellular supporting tissue in the radioles, and a ciliary patch ventrally on the anterior peristomial ring. Only Manayunkia and Monroika lack this supporting tissue (=radiolar skeleton) almost completely, and ventrally at the posterior margin of the anterior peristomial ring there is a ciliary band instead of a ciliary patch ( Bick 2004, 2020, Bick & Armendáriz 2021). In most species, so-called transitional chaetae or transitional uncini ( Bick 2020) may occur in the neuropodia of chaetigers 6 to 8. These chaetae represent an intermediate form of bended narrowly hooded chaetae and thoracic uncini that usually occur in this position. They occur at least in the females of several species ( Atkinson et al. 2020, Bick 2020, Sitnikova et al. 1997). It is not yet known whether there is a character for the beginning of the reproductive period, i.e., whether they are only developed when females reach sexual maturity. It is also not known whether they occur in male. A brood chamber in females is only found in Manayunkia species within the Fabriciidae .