Manayunkiinae, Bick & Bastrop, 2025

Bick, Andreas & Bastrop, Ralf, 2025, Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida), Zootaxa 5661 (1), pp. 1-58 : 7-9

Manayunkiinae subfam. nov.

This new subfamily is proposed for three genera, Echinofabricia Huang, Fitzhugh, & Rouse, 2011 , Manayunkia Leidy, 1859 and Monroika Hartman, 1951 . Brandtika Jones, 1974 is considered here as a junior synonym of Monroika (see Bick & Armendáriz 2021, Remarks and Discussion).

Type genus: Manayunkia Leidy, 1859

Diagnosis (apomorphies in italics). Small-bodied, hemisessile polychaetes with eight thoracic and two, three or four abdominal chaetigers. Three pairs of pectinated radioles, i.e., radioles asymetrically branched; absence of an acellular branchial skeleton; radiolar lobes completely separated from one another. Unbranched vascularized ventral filamentous appendages and branchial hearts. Dorsal lips well developed. Ventral lips or lip-like processes absent. Anterior margin of anterior peristomial ring developed as a membranous collar with wide ventral lobe, narrowly separated mid-dorsally; ciliated band ventrally on posterior margin of anterior peristomial ring. Peristomial eyes present, pygidial eyes present or absent. Spermiogenesis in thoracic chaetigers 6–8, dorsal sperm duct present. Females with darkly pigmented spermathecae; brood chamber and transitional chaetae or transitional uncini may be present in females.

Remarks. There are several characters that are only found in two or three other genera within the Sabellida . These are for example, asymmetrical branching pattern of the radioles, absence of an acellular branchial skeleton, presence of a ciliated band ventrally at the posterior margin on the anterior peristomial ring, presence of transitional chaetae or uncini on last three neuropodia of the thorax, and perhaps also presence of a brood chamber in females. These genera are Manayunkia , Monroika and perhaps also Echinofabricia . Fitzhugh (1989) described the surface of radioles and vascularized ventral filamentous appendages in Manayunkia and in Genus A (now: Echinofabricia ) as minutely wrinkled. The lack of a distinct supporting tissue (=branchial skeleton) is most likely responsible for the fact that the branches of the radiolar crown contract during fixation. A wrinkled surface of the radioles and unbranched vascularised ventral filamentous appendages was also described in Monroika ( Bick & Armendáriz 2021) .

Currently, little is known about the branching of the radiolar crown of Echinofabricia , and there is no description of transitional chaetae or transitional uncini and a brood chamber in this genus. But the asymmetrical branching of the radiolar crown and the lack of a true branchial skeleton are assumed to be ancestral characters. In fact, Manayunkia and Echinofabricia are in a plesiomorphic position in the phylogenetic tree of Fabriciidae ( Huang et al. 2011) . This position is confirmed by the genetic analyses in this paper (see Genetic account).

Bick & Armendáriz (2021) already concluded that Brandtika could be a younger synonym of Monroika . Here, Brandtika is synonymized with Monroika , since in addition to presence of pseudo-spatulate chaetae, the presence of transitional chaetae, the presence of a large central tooth on abdominal uncini and the number of abdominal chaetigers also support the assignment of Brandtika to Monroika .