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Barnacles of the genus Chelonibia differ from all other barnacles that settle on sea turtles by having eight wall plates (Darwin 1854; Ross & Newman 1967). This may not be obvious from a cursory examination of the outer surface of their wall. However, as Darwin (1854) noted, “by slight violence” the broad rostral plate is rendered into three pieces. The remaining derived turtle barnacles, or platylepadids, are commonly much smaller, often inconspicuous and have only six wall plates. These settle predominantly on the skin, usually in great numbers, where they are often found deeply embedded (i.e. Platylepas sp.). At least two species of platylepadids are known to settle and evidently thrive in the mouth, tongue and gullet of sea turtles (i.e. Stomatolepas sp.), clearly an unusual environment for any barnacle (Green 1998; Pilsbry 1910; Wells 1966).

The authorship of Chelonibia testudinaria is attributed to Linnaeus, seemingly by default. Darwin (1854: 393) believed “It is impossible to feel sure which of the three species of the genus Linnaeus had in view, when describing his Lepas testudinaria; but as Spengler has well discriminated the following species under the specific name of caretta, and Ranzani the third species under patula, the present name may, without question, be retained for ...” C. testudinaria, but which one?

Taxonomists inherently prefer to delimit species so that there is no question as to what is in hand. Nonetheless, through no great fault of Linnaeus, the description of testudinaria is somewhat incomplete because we do not know the species name of the host turtle and especially the locality from which his specimens were collected. Noteworthy, Linnaeus’ barnacles in the collections of the Linnaean Society of London are of dubious authenticity (Ross 1963), and it appears many of them had been substituted for “newer, bigger or shinier ones”, not an uncommon practice in the field of “conchcology” in the late 1700’s and early 1800’s. This conundrum poses a dilemma for taxonomists. Because all large white barnacles on the carapace of a sea turtle are simply reported as “testudinaria” it has been assumed, ipso facto, it has a worldwide distribution in warm waters.

Although the jury has not returned with a verdict we do know, from the few collections available to us, based on preliminary morphological evidence, there is more than one species hiding behind the name “testudinaria”. To simply conclude the barnacle in hand is testudinaria has not been provident. Moreover, it has proven detrimental to resolving the status of testudinaria on a worldwide basis. Although taxonomic “splitters” normally win 2 to 1 or better, morphological studies are enticing harbingers for DNA analyses, both of which may discriminate genetically isolated populations.

Over the next year or so we will be undertaking studies to confirm the major question of whether or not there is one or more species of “testudinaria”. Workers in any and all parts of the world interested in having their specimens of “testudinaria” or any other turtle barnacles identified, which we strongly encourage, are welcome to submit them to us (A. Ross). Preferably they should be preserved in 95% ethanol or air dried for DNA analyses, but specimens in 70% ethanol are also acceptable. And, we promise not to charge for our services nor do we guarantee to return the specimens.

One of the intriguing questions we will address and hope to answer is simply, does Kemp’s ridley host the same species of “testudinaria” as does the olive ridley, both of which occur in separate regions of the Caribbean western-Atlantic? Also, can turtle barnacles, in general, serve as indicators of different populations of sea turtles?

DARWIN, C. 1854. A monograph on the sublass Cirripedia, with figures of all the species. The Balanidae (or sessile cirripedes); the Verrucidae, etc., etc., etc. Ray Society, London. 684 pp.

FRICK, M. G. & C. K. SLAY. 2000. Caretta caretta (loggerhead sea turtle) epizoans. Herpetological Review 31(2): 102-103.

GREEN, D. 1998. Epizoites of Galapagos green turtles. In: R. Byles & Y. Fernandez (compilers). Proceedings of the sixteenth annual symposium on sea turtle biology and conservation. NOAA Technical Memorandum NMFS-SEFSC-412, p. 63.

PILSBRY, H.A. 1910. Stomatoloepas, a barnacle commensal in the throat of the loggerhead turtle. American Naturalist 44: 304-306.

REES, E. I. S. & G. WALKER. 1993. A record of the turtle barnacle Chelonobia [sic] testudinaria (L.) in the Irish Sea. Porcupine Newsletter 5(8): 189.

ROSS, A. 1963. Chelonibia in the Neogene of Florida. Quarterly Journal of the Florida Academy of Sciences 26(3): 221-233.

ROSS, A. & W. A. NEWMAN. 1967. Eocene Balanidae of Florida, including a new genus and species with a unique plan of “turtle-barnacle” organization. American Museum Novitates 2288: 1-21.

WELLS, H. A. 1966. Barnacles of the northeastern Gulf of Mexico. Quarterly Journal of the Florida Academy of Sciences 29(2): 81-95.