Orbinia (Polychaeta: Orbiniidae) from the Brazilian coast: two new species and two new records

Abstract

Representatives of the Family Orbiniidae are very common in marine sediments and are found in both shallow and deep waters. Currently, 26 species and 10 genera have been recorded along the Brazilian coast. The specimens examined in this study were collected at depths ranging from 25 to 400 m in the Campos Basin (20-24ºS; 39-42ºW), Rio de Janeiro, in the summer and winter of 2008 and 2009. We describe two new species, Orbinia sagitta n. sp. and Orbinia camposiensis n. sp., and record the occurrences of Orbinia johnsoni (Moore, 1909), which was originally described in California, and Orbinia oligopapillata (López, Cladera & San Martin, 2006), which was previously described from the Pacific coasts of Panama. We provide a key for all the species of Orbinia recorded in the Campos Basin.

The Early Branching Group of Orbiniida Sensu Struck et al., 2015: Parergodrilidae and Orbiniidae

“…Unlike other orbiniids discussed here the last row is situated behind the papilla of postchaetal lamellae (Figure 7B). A similar pattern is found in thoracic neuropodia of Orbinia camposiensis Leão and Santos, 2016 [107]. It differs by a longer first secondary row which is bent frontally under the main rows and a reduced posterior secondary row with two capillaries only (Figure 7C).…”

“…Another example of ambiguous attribution of a species to a genus is Naineris setosa (Verrill, 1900) [106], a large orbiniid with a Naineris-like rounded prostomium bearing only camerated capillaries in the thoracic neuropodia, the diagnostic character of Leitoscoloplos. Furthermore, Orbinia sagitta Leão and Santos, 2016 [107] was erroneously placed into Orbinia lacking subpodal lobes and having Leodamas-like uncini, being similar to Leodamas sinensis Sun, Sui and Li, 2018 [86] (authors' observations).…”

Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America

“…To date, 20 species and subspecies of Orbinia sensu stricto are known with two new species recently described from offshore Brazil (Leão & Santos 2016). Most have branchiae from setiger 5-7, while a small group of three species have branchiae from setiger 8 or more posteriorly.…”

Description of Scoloplos maranhensis sp. nov. (Orbiniidae, Annelida) from tropical Brazilian mangrove

“…Descriptions were based on external morphology, mostly from anterior and median part of the body where most of the diagnostic characters are found. Descriptions followed the classical taxonomic style, following the terminology adopted by Leão & Santos (2016). In addition, the description included body length, always relating to the number of segments.…”

“…Orbiniids are excavators and deposit feeders, with a worldwide distribution occurring from intertidal to abyssal depths (Bleidorn, 2005;López et al, 2006;Solís-Weiss et al, 2009;Dean & Blake, 2015). Currently, two subfamilies are recognized Orbiniinae and Microrbiniinae (Díaz et al, 2012), encompassing 19 genera and more than 150 species, 26 of which have been recorded from Brazil (Blake, 2000;Rouse & Pleijel, 2001;Leão & Santos, 2016).…”