Lepas

Abstract: The development of barnacles has occupied the attention of numerous workers since 1830, when J. V. Thompson discovered that nauplii appeared in their development. This similarity in development with Crustacea led to the transfer of the class Cirripedia from the phylum Mollusca, where it had been classified by Linnaeus, Cuvier, and others, to the phylum Arthropoda. In 1843 Burmeister made an important contribution when he found that in Lepas the larvae passed through two totally different stages, the nauplius and the cypris. He had received what he termed a " ball of Lepas" on which the cypris stages had just attached and the adults were dismissing the newly hatched nauplii. He thus missed the intermediate stages in the developmental series. In 1875 Dr. R. von Willemoes-Suhm studied the life history of Lepas fascicularis while making a cruise from Japan to Sandwich with the Challenger expedition. Concerning this subject he wrote: "My object is to give an idea of the whole development of one Lepas as accurately as possible which seems never to have been done as yet as our knowledge consists of fragments collected mostly in the same way in which Burmeister gained his information." Dr. von \Villemoes-Suhm (1875) found that six different nauplius stages and one cypris stage appeared in the development of Lepas fascicularis, a pedunculate barnacle of the suborder Lepadomorpha. His report, owing to his untimely death, was published by a co-worker. No mention was made of the transformation of the cypris stage into the adult form. No records of a complete study of the development of an operculate barnacle in the suborder Balanomorpha have been found as yet, nor has any other study of another species of barnacle approached the degree of completeness attained by von Willemoes-Suhm. This investigation takes up the life history of Balatns crenatus Bruguiere of the suborder Balanomorpha, from the newly-hatched nauplius to the adult form. Eight nauplius stages and one cypris stage were found. This study was undertaken upon the suggestion of Dr. Harold Heath of Hopkins Marine Station, Pacific Grove, California, and carried on at Stanford University during the academic years of 1928-29 and

Abstract: There is much concern about the potential for invasive species to enter the only marine region left with no known exotics - the Southern Ocean. Attention has focused on planktonic larval travel, shipping (ballast water and hull fouling) and marine debris as transport mechanisms. There is, however, another source of transport for biota across the Polar Frontal Zone - hitchhiking on megafauna, such as seals. In this study we report the frequency and burden of barnacles Lepaa australis attached to Antarctic fur seals Arctocephalus gazella coming ashore to breed at Bird Island, South Georgia. In the austral summers of 2001/2002, 2002/2003 and 2003/2004, female fur seals with barnacles attached arrived at Bird Island in late November/early December and peaked in mid-December. About 4 % of female fur seals carried barnacles, with the mean burden being - 10 barnacles. Pedunculate barnacles seem, therefore, to be entering the Southern Ocean in large numbers every year in the South Georgia region and probably elsewhere. We also found adult barnacles attached to a macaroni penguin and (perhaps the furthest and fastest travelling marine larvae) young stages (cyprids) on the leg ring of a wandering albatross. Barnacle plates provide a hard substratum to which other fouling marine organisms can attach, and thus travel as secondary hitch-hikers. We found polychaete worms (Spirorbidae) and a bryozoan colony (Ceneporella antarctica) encrusting a stalked barnacle attached to a pycnogonan (Collosendeis scotti). We suggest that fouling hitch-hiking barnacles (on migrating megafauna) offer a considerable natural mechanism for potential colonisers of Antarctic waters, This is of particular importance at the current time given the context of strong regional warming in the Scotia Arc-Antarctic Peninsula region.

Abstract: The phylogeny of select Thoracican barnacles was estimated from 18S rDNA sequences. Six new sequences were included, Semibalanus cariosus, Tamiosoma aquila, Balanus glandula, Balanus nubilus, Megabalanus californicus, and Pollicipes polymerus. These were combined with previously published sequences from Genbank. Our maximum likelihood analysis of the data is congruent with previous morphological analyses but differs from the earlier analyses based on 18S sequences, especially in the position of Ibla. We also obtained greater resolution with a gene often considered too slowly evolving to be useful at higher taxonomic levels. Sessile barnacles appear to be monophyletic, but pedunculate barnacles may not be, with the Scapelloidea being the sister taxa to the sessile ones. The Balanidae also appears to be monophyletic, while the enigmatic Heterolepidae is strongly associated with the pedunculate barnacles Lepas and Octolasmus.

Abstract: INFORMATION on the rate of growth of all species of Lepas is scanty. Stanley Kemp, in a letter to J. F. Anton1, quotes three sources, the first of which, referring to an unspecified Lepas, gives an increase in capitulum length of about 1 mm. a day; the second and third, referring to L. anserifera, give increases of 8 mm. in 8 days, 21 mm. in 40 days and 25 mm. in 107 days. In all cases these are minimum rates since they refer to ships and to a buoy known to be free of barnacles at one date and supporting barnacles of quoted size at another, the moment of settling being unknown.