Acasta porata     (Barnacle)
Organism information awaits expert curation
Class: Maxillopoda

Color: Shell white

Shell globular, compartments poorly calcified, brittle and easily broken. Parietes of carinolateral very narrow not reaching basal cup. Compartments fenestrated by longitudinally arranged minute pores through which tissue of host penetrates into its internal cavity. Inner lamina below sheath longitudinally rubbed, pores situated between adjoining ribs. Radii and alae oblique with distinct horizontal lines. Basis cup-formed quadrilateral, bottom pointed, deep and poreless, margin crenated, outer surface with distinct circular growth lines. Scutum triangular, occludent margin straight toothed, longer than tergal margin, apex produced, externally upper 2/3 of valve with a slight longitudinal furrow, horizontal ridges prominent and distinctly crenated with few minute hairs on inferior edges of ridges; articular ridge moderate; articular furrow narrow and shallow; adductor ridge obsolete; pits for adductor and depressor muscles shallow but distinct. Tergum apex produced, spur transversely pointed separated from basi-scutal angle by a distinct narrow space, spur fasciole shallow extending up to apex of valve but becoming indistinct on apical part; articular ridge short limited only to apical 1/3 of valve; articular furrow distinct but shallow towards basal margin; crests for depressor muscles indistinct or obsolete.

The numbers of segments of the cirri:
1)Left row:
anterior ramus: 15-I; 11-II; 14-III, 15-IV; 17-V, 22- VI and
posterior ramus: 8-I; 8-II; 11-III, 18-IV; 22-V, 23-VI
2)Right row:
anterior ramus: 17-I; 11-II; 15-III; 14-IV; 22-V; 25-VI and
posterior ramus: 7-I; 9-II; 11-III, 20-IV; 25-V; 23-VI

In Cirrus I, anterior ramus almost twice longer than posterior ramus, highly setose. Cirrus II anterior ramus a little longer than posterior ramus, pinnate setae seated on protuberant part of segment. Cirri IV to VI posterior rami longer than anterior rami, intermediate segments bear 2 pairs of sub-equal setae; in Cirrus IV segments 1-6 of anterior ramus armed with 1-4 downward curving hook-like teeth in addition to 2 pairs of subequal setae; upper segment of protopodite armed with 8-10 claw-like teeth on its frontal margin. Mouth parts: Labrum with a deep central notch, crest hairy with 1 or 2 teeth. Palpus club-shaped margin setose. Mandible with 4 teeth, 4th tooth minute, 2nd, 3rd, and 4th teeth bifid, inferior angle with 2 or 3 pointed spines. Inner maxilla with straight cutting edge bearing 8 spines, 2 uppermost and 2 lowermost spines larger than intermediate spines, inferior angle rounded with few minute straight setae. Outer maxilla bilobed, upper lobe larger and elongated, apex more or less produced, frontal margin setose, lower lobe small, inner margin with few minute hairs. Penis long, gradually tapering, distinctly annulated, distal and hairy. Basi-dorsal point present and prominent.

Synonym (s)
Acasta porata Nilsson-Cantell, 1921
Acasta porata Broch, 1931
Acasta porata Nilsson-Cantell, 1938a
Acasta porata Rosell, 1972

Common Name (s)
Economic Importance and Threats



• Tamil Nadu, Chennai Coast INDIA
• Tamil Nadu, Kilakarai INDIA

Literature Source(s)
  • NillssonCantell, CA (1938) Cirripedes from the Indian Ocean in the collection of the Indian Museum, Calcutta Memoirs of the Indian Museum The Manager of Publications, Delhi 13 29587 Available at - NIO, RC, Kochi
  • Fernando, SA (2006) Monograph on Indian Barnacles Ocean science and technology Cell, Kochi 9-199 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

Page last updated on:2010-06-29

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