Oxelytrum discicolle (Brullé, 1836), Brulle, 1836

Mullins, Patricia L., Riley, Edward G. & Oswald, John D., 2013, Identification, distribution, and adult phenology of the carrion beetles (Coleoptera: Silphidae) of Texas, Zootaxa 3666 (2), pp. 221-251 : 237-238

Oxelytrum discicolle (Brullé, 1836)

Silpha discicollis Brullé, 1836: 75 (see Peck and Miller (1993) for synonymy).

Davis (1980) reported Oxelytrum discicolle from Texas based on four specimens deposited in the Museum für Naturkunde (Berlin, Germany) that are labeled “Texas, Willacy County, Lyford, VI-69,” collector unknown. Oxelytrum discicolle is a wide-ranging Neotropical species for which Peck and Anderson (1985) examined more than 3,000 specimens as part of their treatment of Latin American Silphidae . Its range in Latin America includes much of South and Central America and most of Mexico. The known Mexican records nearest to Texas are all from mountainous areas in southern Tamaulipas (west of Gomez Farias and Encino, ca. 210 km south of the Texas border) and Nuevo Leon (Chipinque Mesa, west of Linares, etc., approximately 145 km from the Texas border). Peck and Anderson cited the Lyford, Texas, record of Davis, stating that it was the only known United States record for the species. Peck and Kaulbars (1987), after compiling records from 37,000 specimens from more than 56 collections and from other sources, reiterated that the Lyford record was the only record of O. discicolle known from the United States. We have not been able to confirm the presence of this species in Texas, despite additional collecting efforts in the southern part of the state.

Lyford, Texas, is in Willacy County, just south of Raymondville and about 65 kilometers northwest of Brownsville. It is situated at the northern edge of the Rio Grande plain, the former Rio Grande delta. It is a locality almost never seen on beetle specimen records, either in collections or in the “specimens examined” sections of taxonomic works. The few beetle records that we are aware of that were supposedly collected at “Lyford Texas” are all suspected of being in error. The stag beetle, Lucanus (Pseudolucanus) capreolus (Linnaeus) is listed from Lyford, Texas, on a website (Maes [no date], Lucanidae of the World Catalogue). This conspicuous species occurs across much of the eastern United States and in Texas is only confirmed from the eastern-most section of the state (Riley & Wolfe 2003). Certain longhorn beetles ( Cerambycidae ) originally from the Russell Dunn collection are known from specimens labeled as being from Raymondville or Lyford, Texas, but these species are otherwise not known to be part of the Lower Rio Grande Valley longhorn beetle fauna (Daniel Heffern, personal communication, 2007). The Lower Rio Grande Valley area of Texas is arguably one of the most intensively collected regions in the United States for longhorn beetles. A single specimen of the mecopteran Panorpa speciosa Carpenter is known from Texas [Florida State Collection of Arthropods]. It was among papered material recently processed from envelopes. Its original envelope was stamped “Lyford Texas” with a date written in ball-point pen “ May 1965.” The nearest confirmed locality for this species is in central Arkansas (L. Somma, personal communication, 2009).

The locality of Lyford, Texas, is, however, associated with a dealer in biological specimens. A Mr. D. G. Ford is known to have lived in Lyford and he and his wife supplied biological specimens to supply houses during the 1960’s. According to correspondence from Mr. Russell Dunn of Sedona, Arizona (personal communication from Russell Dunn to Daniel Heffern, 2007), they obtained many of their frog and lizard specimens in Mexico. Dunn reports that specimens would be bulk stored in barrels of alcohol then shipped off to purchasers, so there were problems with exact collection dates. Ford sent insect specimens bulked in alcohol to Dunn that were reportedly collected at light in their yard in Lyford. However, Dunn notes, “... they knew they were sending stuff to a youngster and they obviously were not taking me serious, so they may have been throwing in other stuff they got from God knows where.”

In the absence of data to the contrary, the Lyford, Texas, record for Oxelytrum discicolle is here considered a labeling error based on the following: 1) the lack of confirming Texas collection records beyond the four original specimens labeled “Texas: Willacy County, Lyford, VI-69 ” with no collector; 2) the sizable disjunction between the Texas record and the nearest confirmed locality for this species; 3) the known existence of other suspect insect records from Lyford, Texas; and 4) the knowledge that a dealer in biological specimens lived in Lyford during the 1960s, that he often traveled to Mexico (where Oxelytrum is common) to acquire specimens, and that he practiced poor specimen labeling. A plausible scenario has Mr. Ford collecting these specimens in Mexico, then selling them in bulk with other insect specimens to a buyer who simply labeled the entire lot as being from Lyford, Texas.