Monroika Hartman, 1951

Bick, Andreas & Armendáriz, Laura, 2021, A new freshwater fabriciid species (Sabellida, Fabriciidae) from the Uruguay River, Argentina, with some remarks on the relationships of Monroika Hartman 1951, Manayunkia Bourne, 1884 and Brandtika Jones, 1974, Zootaxa 4966 (2), pp. 187-201 : 189-190

Monroika Hartman, 1951

Type species: Manayunkia africana Monro, 1939 , by original designation.

Diagnosis (emended). Eight thoracic and two abdominal chaetigers. Radioles asymmetrically branched, i.e. pectinated radioles present; acellular radiolar skeleton absent. Unbranched vascularized ventral filamentous appendages present. Dorsal lips erected, broadly rounded. Anterior margin of anterior peristomial ring developed as a membranous collar with rectangular ventral lobe, narrowly separated middorsally; ciliated band ventrally on posterior margin of anterior peristomial ring. Inferior thoracic notochaetae narrowly hooded, or pseudospatulate on chaetigers 2 or 3–5. Thoracic uncini with one slightly offset larger tooth above main fang followed by series of smaller teeth. Dentate region of abdominal uncini with a single central tooth proximally, surmounted distally by series of equal-sized smaller teeth; manubrium significantly longer than dentate region. Peristomial eyes black, pygidial eyes absent.

Remarks. The genus diagnoses for Monroika ( Hartman 1951, Jones 1974) mentioned the presence of pseudospatulate chaetae. These chaetae do not occur in the species described here. The presence of pseudospatulate chaetae, the occurrence of which is not consistent within the genera of Fabriciidae anyway, is therefore not considered a generic character for Monroika . The genus diagnosis is also emended by the fact that black peristomial eyes occur. Peristomial eyes are present in almost all species of Fabriciidae .

The genus Monroika is mainly characterized by the presence of asymmetrically branched or pectinated radioles, unbranched vascularized ventral filamentous appendages, a ciliated band on posterior margin of anterior peristomial ring and two abdominal chaetigers. Monroika shares with Manayunkia the first three characters but it differs in the number of abdominal chaetigers from Manayunkia .

However, the thoracic and abdominal uncini of Monroika and Manayunkia are also different. Monroika has thoracic uncini with a single large tooth slightly offset over main fang followed by a series of smaller teeth whereas the thoracic uncini of Manayunkia are characterized by series of equal-sized or progressively shorter teeth above the main fang. A single large tooth is absent. The dentate region of the abdominal uncini in Monroika has a single central tooth proximally, surmounted distally by a series of equal-sized smaller teeth. A large central tooth is absent from the proximal dentate region in Manayunkia . The dentate region of abdominal uncini in Manayunkia consists of many rows of teeth of the same size. A large central tooth on the abdominal uncini is present only in Brandtika species ; it is absent in all other fabriciid genera.