My first exposure to this species occurred in the insect taxonomy class last year, when a student brought in a beetle that looked somewhat like a cross between a buprestid and a pistol round dusted with clumped sugar. I knew exactly what family it was as I had collected a few at light traps in Costa Rica. I was surprised to hear she collected this beetle in the slightly less exotic locale of her apartment complex in Cary, NC. It was a turtle beetle, Chelonariidae. An immediate perusal of American Beetles (Ivie 2002) revealed that she was lucky indeed.

Chelonarium lecontei is the only North American representative of Chelonariidae, the turtle beetles, a small family containing 3 genera. Chelonarium is found throughout the tropics, Pseudochelonarium is from Southeast Asia, and monotypic Brounia is restricted to New Zealand (Ivie 2002). True to the common name, the legs and antennae of all chelonariids are strongly retractile. When a turtle beetle is fully retracted into its bullet or seed shaped habitus, it takes some care to even realize one is looking at a beetle. The antennae fit into grooves between the coxae. Preserved specimens are usually retracted; the heads are visible in 3 or 4 of the 40 specimens in the NCSU collection. We have a decent holding as C. lecontei is considered “extremely rare” (Coats & Selander 1979) to “at least rare in collections” (Tuff 1975).

The retractile position of the legs does not lend them much dorsoventral flexibility. So, does flipping a turtle beetle onto its back render it helpless, a mirror of the old rumor about doing the same to a true turtle? Other beetles have highly specialized methods for righting themselves, such as the clicking mechanism in elateroid beetles. Males of Chelonarium lecontei flip themselves over by exserting their genitalia, opening their elytra, and pushing their head against the ground. See Coats & Selander 1979 for illustrations and discussion. Females are more rarely collected, and there are no published accounts of how they right themselves.

Though the family is very morphologically unusual, its phylogenetic position is fairly well resolved. It is clearly a member of the byrrhoid and dryopoid group of beetles. It was previously a subfamily of Byrrhidae. The parsimony analysis in Hunt et al (2007) placed it near Ptilodactylidae, and other analytical methods in that paper place Chelonariidae close to or within Elmidae.

Chelonarium lecontei was described by Thomson in 1867 in honor of the prolific 19th century coleopterist John Lawrence LeConte, whom Wikipedia hyperbolically designates “the most important American entomologist of the 19th century.” Chelonarium Fabricius 1801 is a reference to the genus Chelonia, a well known group of vertebrate turtles.

The family is easy to diagnose because it is pseudotetramerous, and has retractile appendages. Chelonarium has a strongly carinate pronotum anteriorly. For more information check American Beetles (Ivie 2002) or Delta Elateriformia (Lawrence et al 2005). The species is shiny, dark reddish to black, and has small tufts of whitish setae. The male genitalia are diagnostic however the genus severely needs revision.

Adults can be most reliably collected at UV or Hg lights at night. Two specimens at the NCSU collection were hand collected off trees at night. Ivie (2002) suggests flight intercept traps and beating vegetation at night as two other collecting methods, though none of our specimens were collected this way.

The life history of Chelonarium lecontei larvae is not known. Other species of Chelonarium are generalist saprophages in various environments, such as leaf litter and under bark. A few species are likely myrmecophilous, though the larvae so far found in ant waste piles appear to be facultative (Ivie 2002). Some older references claim that the larvae are aquatic or semiaquatic but this not true (Spangler 1980).

Chelonarium lecontei adults are rare visitors to lights in damp forest environments. The one specimen I personally have collected was at a bathroom light at a campsite in Uwharrie National forest, near Charlotte. It was stuck in a spider web, alive, and the spider seemed to be uninterested in it, though this may have been due to size moreso than the beetle’s defenses. The larvae are not well known but sifting leaf litter or moss may reveal more about them.

The species is found in the southeastern US, from Florida to Texas in the west, and North Carolina in the north. Raleigh may be at the northernmost edge of its range. None of the specimens in our museum are known from north of Raleigh. The NCSU insect museum also holds three specimens of Chelonarium punctatum and 25 undetermined Neotropical Chelonarium.

• Coats, J. R. and R, B. Selander. 1979. Notes on Chelonarium lecontei Thomson (Coleoptera: Chelonariidae), including Description of an Unusual Righting Behavior.
  The Coleopterists Bulletin Vol. 33, No. 1 (Mar., 1979), pp. 57-59 http://www.jstor.org/stable/4000158?seq=1
• Hunt, T., J. Bergsten, Z. Levkanicova, A. Papadopoulou, O. St John, R. Wild, P. M. Hammond, D. Ahrens, M. Balke, M.S. Caterino, J. Gómez-Zurita, I. Ribera, T. G. Barraclough, M. Bocakova, L. Bocak, and A. P. Vogler. 2007. A comprehensive phylogeny of beetles reveals the evolutionary origins of a super-radiation. Science 318: 1913-1916.
  http://www.bio-nica.info/biblioteca/Hunt2007BeetlesPhylogeny.pdf
• Ivie, M. A. 2002. Family 50. Chelonariidae. pp. 139-141 in Arnett, R.H., Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). American Beetles. Volume 2. Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press LLC, Boca Raton, FL.
• Lawrence, J.F., Hastings, A.M., Dallwitz, M.J., Paine, T.A., and Zurcher, E.J. 2000 onwards. Elateriformia (Coleoptera): descriptions, illustrations, identification, and information retrieval for families and subfamilies. Version: 9th October 2005. http://delta-intkey.com
• Spangler, P. J. 1980. Chelonariid Larva, Aquatic or Not? Coleopterists Bulletin 34(1):105-114
• Tuff, D. W. 1975. New Distributional Record for Chelonarium lecontei Thomson (Coleoptera: Chelonariidae). The Southwestern Naturalist, Vol. 19, No. 4 (Jan. 20, 1975), pp. 437-439
  http://www.jstor.org/stable/3670402?seq=1