Scirtidae, Fleming, 1821

Epler, J. H., 2009, More new distribution records for Florida water beetles (Coleoptera: Dytiscidae, Elmidae, Hydrophilidae, Scirtidae), with additional notes on Scirtes oblongus Guérin-Méneville, Insecta Mundi 2009 (87), pp. 1-4 : 3

Scirtidae

Sarabandus robustus (LeConte) . A single male specimen of this large scirtid was found in a tray of unsorted material in the FSCA: Alachua Co., Paynes Prairie State Preserve, Malaise trap in swamp, 10- iv-1999, leg. Randall W. Lundgren. This is the first, and southernmost, record for this genus and species from Florida. Ciegler (2003) had previously recorded it from Myrtle Beach in South Carolina.

Scirtes oblongus Guérin-Méneville. Champion (1897) considered there to be two forms of this species: the “pallid form” ( Fig. 1 ) originally described by Guérin-Méneville (1861: 546) and a vittate form ( Fig. 2 ) described and illustrated by Champion (1897: 609 and Plate 26, figs. 28, 28a). I follow Champion (1897) in considering these as two forms of a single species. Florida records for the immaculate form include: one female, Osceola Co., Lake Gentry boat ramp, 12-v-2007, leg. D.R. Denson; one female, Palm Beach Co., Delray Beach, Country Lake, mercury vapor light, 1-vi-1993, leg. Vince Golia. Florida records for the vittate form include: one specimen, Highlands Co., Lake Placid, Archbold Biological Station, mercury vapor light, 4-vi-1994, leg. Vince Golia; one specimen, Palm Beach Co., Delray Beach, Country Lake, mercury vapor light, 4-vi-1993, leg. Vince Golia; one male, Palm Beach Co., Lake Worth, Harbour Greens Drive, mercury vapor light, 21-vi-2007, leg. Vince Golia. Originally described from Mexico (Yucatan) and also recorded from Mexico (Vera Cruz and Yucatan) and Guatemala ( Champion 1897); these are the first records for this species from the United States and the Nearctic.

There is also material of this species from the Cayman Islands in the FSCA. Through the kindness of Warren Steiner (National Museum of Natural History, Smithsonian Institution, Washington, D.C.), I have examined material from Cuba identified as Ora sexlineata (Chevrolat) . I am considering S. oblongus to be a senior synonym of Scirtes sexlineatus Chevrolat and S. interruptus Chevrolat ( Chevrolat 1870: 69) , both placed by Pic (1914: 40) in Ora .

I have also examined specimens from Cuba, Mexico and Costa Rica of a third form ( Fig. 3 ) in which the vittae are coalesced into a single broad dark stripe on each elytron, with a thin light sutural stripe and light outer margin; there are also intermediates between the vittate and this broadly striped form. Male genitalia of the vittate form ( Fig. 5 ) and broadly striped form are similar; only females of the immaculate form were available and thus are not comparable.

Guérin-Méneville’s original description mentions three weak costae on each elytron. These costae are more evident on the immaculate form and the broadly striped form; they are very weak or absent on most of the vittate forms.

Its elongate shape is unusual for a Scirtes , which are usually more broadly oval. In general habitus, this species resembles an Ora or, at a quick glance, a chrysomelid. In his description of S. sexlineatus, Chevrolat (1870: 69) noted “... ressemblant beaucoup à certaines Alticites du genre Oedionychis .”

As in species of Ora , S. oblongus also has a large laminate prosternal process that reaches the apices of the fore coxae, and the pronotum and elytra are moderately explanate laterally. The hind coxae ( Fig. 4 ) are more typical for a Scirtes ; they are not contiguous but are narrowly separated and opposed along their entire inner margin, with the base of the trochanter partially hidden by the posteroventral margin of coxae (the trochanter base is fully exposed in Ora species ).

Figures

Figure 1-5. Scirtes oblongus. 1) Immaculate form, Palm Beach County, FL. 2) Vittate form, Highlands County, FL. 3) Broadly striped form, Vera Cruz, Mexico. 4) Hind coxae, vittate form, Palm Beach County, (margins emphasized). 5) Male genitalia, Havana, Cuba.