First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family

Abstract

The family Longosomatidae Hartman, 1944 (Annelida: Polychaeta) is newly reported for Icelandic waters. The diversity, taxonomy and ecology of this poorly-known monogeneric family are reviewed based on material collected during the BIOICE project. Two species of the genus Heterospio are recorded and redescribed: Heterospio longissima Ehlers, 1874 sensu Hartman (1965) and Heterospio reducta Laubier, Picard and Ramos, 1972-73. Several body structures of high taxonomic relevance in the genus are reviewed and discussed.

A new species of Heterospio (Annelida, Longosomatidae) from the Indian Ocean

“…Intraspecific variation is also reported whenever recorded (e.g., segment size, branchiae arrangement). For the delimitation of body segments we follow Parapar et al (2014); these authors propose that chaetae are located on the anterior border of segments and therefore the length of a segment should be considered as the distance from the chaetal bundle (or ring) to the chaetal bundle of the next chaetiger. For comparative purposes, one specimen collected by Rosenfeldt (1989) off the Sudanese coast in the Red Sea was also studied.…”

“…Following Parapar et al (2014), the terms "thorax" and "abdomen" are not used in the diagnosis due to the lack of a clear criterion about their limits. The presence of nuchal organs on the prostomium was included in the diagnosis.…”

“…The presence of nuchal organs on the prostomium was included in the diagnosis. The range of 7−9 short anterior chaetigers provided by Borowski (1994) is modified to 6−8, following Parapar et al (2014). Peristomial palps were qualified as "easily deciduous" because they are not reported in most descriptions.…”

“…This species was subsequently reported in numerous localities in the same ocean and in the Sea of Japan (see fig. 8 in Parapar et al 2014). In the Indian Ocean the only records of the genus correspond to one specimen of H. longissima off the coast of Sudan, Red Sea (Rosenfeldt 1989;Türkay 1996;Wehe & Fiege 2002), and two specimens off the Indian and Pakistani coast of the Arabian Sea (Hartman 1974;Wehe & Fiege 2002;Rao 2005;Kazmi & Naushaba 2013) (Fig.…”

“…According to Rouse (2001) their elongated body is characterized by an anterior region composed by 7-9 short segments and provided with 3-8 pairs of branchial filaments, a post-branchial region composed of elongate segments and a bulbous posterior region with terminal pygidium. The length of the first elongated segments, number of pairs of branchiae and chaetal types are the main taxonomic characters used to differentiate between species (e.g., Wu & Chen 1966;Laubier et al 1973;Wilson 2000;Bochert & Zettler 2009;Parapar et al 2014).…”