Questinae Hartman, 1966b

Blake, James A., 2021, New species and records of Orbiniidae (Annelida, Polychaeta) from continental shelf and slope depths of the Western North Atlantic Ocean, Zootaxa 4930 (1), pp. 1-123 : 109-110

Subfamily Questinae Hartman, 1966b . New status

Diagnosis. Same as genus Questa (below).

Remarks. It is now generally agreed that Questa belongs in the Orbiniidae rather than as a stand-alone family (Read & Fauchald 2020b). Based on molecular data by Bleidorn (2005), Bleidorn et al. (2009), and Rousset et al. (2007), two species of Questa formed a separate clade within the Orbiniidae . While the serrated and/or camerated capillaries and furcate setae are similar to those found in other species of Orbiniidae , Questa species have unique setal and reproductive characteristics that differ from other orbiniids. The reproductive characteristics of Questa have been shown to exhibit similarity to oligochaetes in being sexually dimorphic with males having distinct cuplike dorsal folds believed to serve as male copulatory organs and females with seminal receptacles and similar gland-like epidermal areas similar to a clitellum ( Giere & Riser 1981; Giere et al. 2008). However, the bidentate hooks or crotchets found in all species of Questa are similar to those of some deep-sea species of Paraonidae , genus Levinseni a. At present Questa species are not assigned to either of the two orbiniid subfamilies. Based on unique morphology and supported by molecular data, I propose that Hartman′s family Questidae be revalidated as a sub- family within the Orbiniidae .

Genus Questa Hartman, 1966b

Type species: Questa caudicirrata Hartman, 1966b , by monotypy.

Diagnosis. (Emended) Body elongate, threadlike, up to 10 mm long with 45–65 setigerous segments; body segments cylindrical in cross section; setigerous segments with 2–3 intersegmental annulations in anterior setigers, up to 7–8 in middle segments, decreasing posteriorly. Prostomium conical, tapering to narrow rounded tip; nuchal organs paired slits on posterior lateral margins. Peristomium typically with 2–3 asetigerous rings, with dorsal surfaces smooth, entire; ventrally forming anterior and posterior lips of mouth. Thoracic and abdominal regions only vaguely identified by shorter, wider segments anteriorly and longer, narrower segments posteriorly. Paired branchiae present dorsally in posterior segments or entirely absent. All parapodia biramous, composed of low mounds bearing noto- and neurosetae; setae serrated or weakly camerated capillaries and bidentate hooks with geniculate shafts in both rami; furcate setae present or absent in notopodia. Pygidium with 0, 2, or 4 anal cirri. In mature males segments 13–14 (15) with elevated cup-like or slit-like dorsal fold. Mature females of almost all species with more-or- less papillated glandular epidermis in anterior segments. Extension and shape of papillation on females species-specific, but also depending on stage of maturity. Egg region (mostly segments 12–13) of mature females slightly swollen due to formation of 2–3 large eggs.

Remarks. In addition to the external morphology highlighted in the Diagnosis, species of Questa have been discovered to have reproductive morphology that bears some similarity to that of oligochaetes. Both sexes have gonads limited to a few anterior segments that exhibit external genitalia ( Giere & Riser 1981). Females have a glandular epidermis on a few anterior segments that resembles the clitellum of oligochaetes ( Bleidorn & Helm 2019). The males have sperm sacs in segments 10–12 that connect to gonopores opening externally into an inflated dorsal fold on setiger 13 that is an unusual cup-like structure.

Reproductive behavior has not been observed, but Giere & Riser (1981), working with Questa trifurcata , hypothesized that males attach their cup-like dorsal fold to the spermathecal segments of females. The worms would then separate after the spermathecae are filled. Afterwards, the female would secrete a cocoon containing fertilized eggs. A cocoon of Q. trifurcata found and cultured by Giere & Riser (1981) contained a single embryo that hatched with seven setigers after a month. The juvenile was identified as Q. trifurcata due to the setae, which in addition to the capillaries and characteristic hooks included a furcate seta.

Ten species of Questa are known globally; a single species, Q. trifurcata , occurs along the eastern U.S. from Maine to New Jersey (Hobson 1970; Giere & Riser 1981; Giere & Erséus 1998). This species was collected on Georges Bank during the benthic monitoring program performed for MMS in the 1980s. The specimens recorded here constitute a range extension of the species from nearshore intertidal and subtidal depths to the outer continental shelf.