Marine Polychaete Annelids of Easter Island

Abstract

This study increases the number of species of marine polychaete annelids known t o occur at Easter Island from 11 t o 60, of which 43 are identified t o species. Nearly goo/, of these occur in the tropical Indo-West Pacific region, but 60(1/n are of circumtropical distribution. The strong Indo-West Pacific zoogeographic affinity is consistent with other taxa of Easter Island inshore marinc animals for which data are available, the fishes, corals, and gastropod molluscs.Polychaete species composition and abundance were determined in substrate samples from two types of microhabitat in a tidepool. A sample of 290 ml of sand and 70 ml of algae contained 1,779 specimens of 41 species of polychaetes (species diversity H' = 2.57). A basalt boulder of surface area 340 cinZ contained a polychaete assemblage of 864 specimens of 35 species (H' = 2.49).Population density of the latter sample is equivalent t o 25,400 polychaetes/m2. Of the 49 species present in the two samples, 34 were identified t o species. Although 27 species (55%) were common to both samples, similarity as measured by C,, which weighs differences in relative abundance, was only 24%. More than half of all polychaetes present in the two samples belonged t o the family Syllidae; they comprised 65% of the individuals in the sand-algae sample and 350/, in the boulder sample. Spirorbinae predominated numerically in the boulder sample (40%). Chaetopteridae and Spionidae (8%) were thc next most abundant families in t h e sand-algae sample.

Guía y claves para el reconocimiento de las subfamilias, géneros y especies de Syllidae registradas a lo largo de la costa de Chile, archipiélago Juan Fernández e isla de Pascua (Annelida: Phyllodocida: Syllidae)

“…Localidad de registro en isla de Pascua: entre bahía Hanga-Roa y Hanga-Piko, en poza de marea (Kohn & Lloyd, 1973 Género Parapionosyllis Fauvel, 1923Parapionosyllis Fauvel, 1923 26. Parapionosyllis brevicirra Day, 1954 Parapionosyllis brevicirra Day, 1954: 16, fig.…”

“…Taltal; El Quisco (33°23' S), S de Algarrobo; desembocadura de la quebrada de Córdova (33°26' S), N de El Tabo (HartmannSchröder, 1965). Isla de Pascua, entre HangaRoa y Hanga-Piko, en poza de marea (Kohn & Lloyd, 1973).…”

“…Distribución: océano Atlántico Norte y Sur; mar Mediterráneo; mar Negro; mar Rojo; costa de California; México occidental (Kohn & Lloyd, 1973); Argentina (puerto Madryn, golfo Nuevo) (Hartmann-Schröder, 1962); Chile: desde Iquique (20°12' S) hasta la quebrada de Córdova (33º26' S) e isla de Pascua. Muy probablemente la cita de esta especie en isla de Pascua se refiere a otra especie diferente.…”

“…Localidad de registro en isla de Pascua: entre bahía Hanga-Roa y Hanga-Piko, en poza de marea (Kohn & Lloyd, 1973).…”

“…Branchiosyllis verruculosa: Licher, 1999 Localidad tipo: Australia sudoccidental. Referencia para isla de Pascua: Syllis (Typosyllis) verruculosa: Kohn & Lloyd, 1973, p. 695. Localidad de registro en isla de Pascua: entre bahía Hanga-Roa y Hanga-Piko, en poza de marea (Kohn & Lloyd, 1973). Distribución: Zanzíbar (Monro, 1939); Australia (Augener, 1913;San Martín et al 2008 (Grube, 1855), pero posiblemente se trate de otra especie, ya que la verdadera H. spongicola parece estar restringida a las costas europeas y del Mediterráneo, a pesar de haber sido citada en todo el mundo (Lattig et al 2007).…”