Tubicolous polychaete worms (Annelida) from Bahía de Chamela Islands Sanctuary, Mexico, with the description of a new bamboo worm

Fanworms: Yesterday, Today and Tomorrow

Sabellida Levinsen, 1883 is a large morphologically uniform group of sedentary annelids commonly known as fanworms. These annelids live in tubes made either of calcareous carbonate or mucus with agglutinated sediment. They share the presence of an anterior crown consisting of radioles and the division of the body into thorax and abdomen marked by a chaetal and fecal groove inversion. This study synthesises the current state of knowledge about the diversity of fanworms in the broad sense (morphological, ecological, species richness), the species occurrences in the different biogeographic regions, highlights latest surveys, provides guidelines for identification of members of each group, and describe novel methodologies for species delimitation. As some members of this group are well-known introduced pests, we address information about these species and their current invasive status. In addition, an overview of the current evolutionary hypothesis and history of the classification of members of Sabellida is presented. The main aim of this review is to highlight the knowledge gaps to stimulate research in those directions.

Sclerozoan and fouling sabellid worms (Annelida: Sabellidae) from Mexico with the establishment of two new species

Background

The sabellid genera Anamobaea Krøyer, 1856 and Notaulax Tauber, 1879 are two of the most attractive polychaete worms in coral reefs. Anamobaea is represented by two Caribbean species and Notaulax with 24 species from around the world, six of them previously known to tropical America. During examination of fouling biota and sclerozoans from Mexico, Anamobaeaorstedii Krøyer, 1856 was found in coral reefs from the southern Gulf of Mexico and three species of Notaulax were identified to the Mexican Pacific, two of them being new species to science.

New information

Anamobaeaorstedii Krøyer, 1856 is first reported as sclerozoan of dead coral from the southern Gulf of Mexico. An amendment to the generic diagnosis of Anamobaea is provided, based on the presence of a higher number of skeletal cells than previously recorded; height, shape and exposition of the anterior peristomial ring; the non-fusion of dorsal collar margins to faecal groove; shape of collar chaetiger and abdominal chaetae and distribution and shape of radiolar ocelli. Notaulaxcalifornica (Treadwell, 1906) is reported as fouling in buoys and docks from the Gulf of California. Two new species of Notaulax are described: the former was found in hull and dock fouling from La Paz (Gulf of California) and the second one as sclerozoan of oysters from a dock fouling in Acapulco (south Mexican Pacific). In addition, reproductive features are described for the first time for A.orstedii which is a simultaneous hermaphrodite with female and males gametes found within the same segments of abdominal region. Oocytes develop synchronously and sperm morphology (spherical nucleus and rounded acrosome, four spherical mitochondria and a long free flagellum) suggest an adaptation to broadcast spawning and external fertilisation. Species of Notaulax here examined were gonochoric, with gametes distributed in abdominal segments.