Leitoscoloplos Day 1977

Genus Leitoscoloplos Day, 1977

Type-species: Haploscoloplos bifurcatus Hartman, 1957, designated by Day 1977.

Diagnosis. Prostomium pointed, conical; peristomium typically with one achaetous ring, but with additional superficial annulae on some species. Branchiae lacking, or present from posterior thoracic, transitional, or abdominal setiger. Posterior thoracic setigers with 0–2 postsetal lobes and 0–2 subpodial lobes; abdominal setigers with 0–4 subpodial papillae; stomach papillae rare, interramal cirri present or absent. Thoracic neurosetae including only capillaries. Without abdominal neuropodial spines, with 2–3 imbedded aciculae present or absent.

Remarks. Day (1977) determined that the type species of Haploscoloplos Monro, 1933a (H. cylindrifer (Ehlers, 1904)) possessed an anterior row of short hooks in the thoracic neuropodia in addition to capillaries and thus belonged to the genus Scoloplos. He examined a specimen from near Christchurch, NZ; South Island, New Zealand, near the type locality of the species. He therefore proposed a new genus, Leitoscoloplos to include those remaining species formerly assigned to Haploscoloplos. Most of the known species of Leitoscoloplos were summarized by Mackie (1987). Those species have been reconsidered as part of this study. Several new species, new combinations, and new synonymies are proposed from the materials examined as part of this study and are listed below.

An assessment of branchial distribution suggests that Leitoscoloplos can be divided into five groups of species. Geographically, species within these groups also have some affiliation to their distribution globally. For example, the two abranchiate species in Group A are deep-sea abyssal species; the three species in Group C occur only along the Atlantic and Gulf coasts of North America, and all 11 species in groups D and E occur in the southern hemisphere of which seven occur in the Southern Ocean. The 11 species in Group B are the most ubiquitous, occurring widely over the world’s oceans.

This study suggests that previous records of certain widely recorded species need to be reevaluated. For example, the record of Haploscoloplos kerguelensis from the eastern Mediterranean by Ramos (1976) is most certainly an undescribed species (see Discussion of L. kerguelensis below). Similar identifications of Haploscoloplos or Leitoscoloplos kerguelensis from Asia also need to be reconsidered (see below). One undescribed deep-sea species of Leitoscoloplos was recently identified from offshore Brunei Darussalam in the South China Sea (Blake unpublished).

According to this revision, Leitoscoloplos species are categorized as follows: