Xray Conchology

By Harry G. Lee

     Over the years, several shell enthusiasts have applied Xray techniques to allow a better understanding of the structure of molluscan shells, but the following account may be one of the few in which shells were captured on film from a characteristic niche, but were invisible to the naked eye.

     At least a few of us are familiar with the "stove-pipe shell," a long irregular to nearly rectilinear shelly tube which may reach six feet in length. Over the course of my shelling experience, various luminaries have written accounts of this natural history object with widely variant degrees of veracity. Some popular articles attribute their tube to a giant gastropod "worm-snail" (example Vermicularia or Vermetidae), others to a worm (?Annelida). In fact, the author of the scientific name, Serpula polythalamia Linnaeus, 1767 placed it in a genus with an Annelid worm, and in 1758 thought it was conspecific with a Vermetid (wormsnail).

Author's son (185.4 cm.) with specimen described herein.

Author's son (185.4 cm.) with specimen described herein.

     For many years a solitary, intact, alcohol-preserved specimen of this creature, collected in the Solomon Islands, reposed in London's British Museum (Natural History). Almost 30 years ago Dr. Ruth Turner broke it apart and extracted the animal. In 1966 she reported her findings in an extensive monograph on shipworms - the benchmark work on the group. The anatomic features allowed her to hypothesize that Kuphus was the most primitive of the shipworms. She learned that the habitat was the mud of mangrove swamps in the torrid S. W. Pacific. Because of the lack of ridges on the anterior margin of the valves, she deduced that the animal was incapable of burrowing in wood. Based of these perspectives, she hypothesized that the ancestral shipworm was probably a mud-dwelling burrower more akin the Kuphus and any other surviving stock.

     Dr. Turner didn't describe the tube of Kuphus exhaustively. Let me tell you what I have observed. Until recently very few intact specimens were available to collectors. This year two Sanibel shell dealers Larry Strange and Al Deynzer, have gotten "good" specimens of this natural history object from the Philippines. An intact specimen in my collection measures 40 inches in length. It slowly tapers from the 4 1/2 inch diameter closed rounded anterior end to a septate open posterior end which is subovate and about 1 1/2 inches across (See illustration). It is through this pair of openings that the animal extends its inhalant and excurrent siphons - each of which shares the aperture with a specialized set of "pallets" (like all other shipworms) used to close the openings in the tube when the siphons have withdrawn - as with an environmental threat.

     One of the fun things related to "shell" study is getting new perspectives on the critters. The accompanying photos (See below) shows a view of my Kuphus tube (much reduced) By shaking and twisting the specimen, I was able to position the shells (trapped inside after the shipworm' s demise) in various poses. I'll let Dr. Turner reconstruct the 3D appearance of these shells, which measure slightly over 1 inch in maximum length.

Xray of anterior end of Kuphus

Xray of anterior end of Kuphus

 

Reference: Turner, R. D. (1966) A Survey & Illustrated catalog Teredinidae (Mollusca: Bivalvia) Museum of Comp. Zoology, Cambridge.

Back