Acasta glans   Lamarck,  1818 (Barnacle)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Arthropoda
Class: Maxillopoda
Order:Sessilia
Family:Archaeobalanidae

Description
Color: Pale dirty reddish

The surface is generally studded with small calcareous points. The parietes of the carino-lateral compartments are about one fourth of the width of the parietes of the lateral compartments.
Scuta: Slightly narrow, thick and convex. Strongly striated in longitudinal lines. The articular ridge is very feebly developed.
Terga: In full grown specimens, the spur is half the width of the whole valve, and is truncated; its basal edge being parallel to the basal margin of the valve. The articular ridge and crests for the depressors muscles are very feebly developed.
Internal structure of the parietes: The inner surface of the parietes is quite smooth, without even a trace of ribs or teeth. But the most important character is that the internal lateral margins on both sides of each compartment, from the sheath to the basis, project inwards and form a rim; so that when the shell is viewed from within, the six sutures are seen to be strengthened by six double columns.
Basis: This is moderately cup-formed. The edge, in order to meet the basal points of the inwardly projecting lateral margins of the six compartments has six knob-like teeth. These are placed at unequal distances, for two on each side stand near each other, owing to the narrowness of the carino-lateral compartments. The degree of their development varies extremely; when most developed, as in the specimen figured, each tooth is bifid and a little hollowed out, so as to receive the points of the two inwardly projecting margins which form each suture. Ridges, more or less prominent, running from each of the six marginal teeth, extend towards the centre of the cup. These six teeth cannot be seen from the outside. The edge of the cup is rarely crenated; but I have seen two instances in which this was the case.
Cirri: In the first pair, the rami are not quite unequal; the longer ramus being about twice as long as the shorter. In the third pair, there are some very minute, thick, upwardly-pointing spines. In the fourth pair, the spines are a little more crowded, with, longer dorsal tufts, than in the sixth pair; and they are mingled with some very minute, thick, upwardly pointing spines. In young individuals, there are only three pairs of main spines on the segments of the sixth pair, instead of four parts.


Synonym (s)
Acasta glans Lamarck 1818
Acasta glans Darwin 1854
Acasta glans Hoek 1913
Acasta glans Nilsson-Cantell 1938a
Acasta glans Utinomi 1969

Common Name (s)
Economic Importance and Threats

Ecology

Biogeography


• Orissa, Ganjam Coast INDIA (Record: 2006)
• Madras Presidency INDIA (Record: 2006)

Literature Source(s)
  • 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 - http://www.marinespecies.org

Page last updated on:2012-05-22

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