Cercyon floridanus Horn, 1890,

Arriaga-Varela, Emmanuel, Seidel, Matthias, Deler-Hernandez, Albert, Viktor Senderov, & Fikacek, Martin, 2017, A review of the Cercyon Leach (Coleoptera, Hydrophilidae, Sphaeridiinae) of the Greater Antilles, ZooKeys 681, pp. 39-93: 52

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Cercyon floridanus Horn, 1890


Cercyon floridanus Horn, 1890  Figures 2 d–f, 7 a–d, 16a

Cercyon floridanus  Horn, 1890: 303.

Cercyon floridanuus  Smetana ( Thomas et al. 2013: 33 lapsus calami)

Figures in Flickr.


Type locality.

Florida (without specific locality).

Greater Antillean specimens studied.

CAYMAN ISLANDS: Grand Cayman: blacklight trap, vi.1992, leg. blacklight trap (1 male; FSCA), blacklight trap, vi.1992, lgt. P. Fitzgerald (1: FSCA); Queen Elizabeth Botanic Garden, blacklight trap, 28.v.2009, leg. Thomas, Turnbow & Ball (1: FSCA); Georgetown, blacklight, 30.iii.1973. E.J. Gerberg (1: FSCA).

Published Greater Antillean records.

GRAND CAYMAN: 3 km W Colliers, 19°21'N, 81°07'W ( Thomas et al. 2013).


Body size 2.35-2.70 mm; dorsal surface of head (Fig. 2d) completely black, pronotum black sometimes with undefined piceous areas at lateral margins; elytra black (Figs 2d, f), with large rather sharply-defined yellowish to reddish-yellow lateroapical areas reaching apex lateralmost interval, medial ridge of prosternum anteriorly very weakly projected ventrally; mesoventral plate (Fig. 7d) very wide, ca. 1.9 × as long as wide; metaventrite (Fig. 7d) without femoral lines, with broad raised pentagonal area (about 0.67 × as long as wide) with large, deep and semicircular punctures; first abdominal ventrite without spiniform process in both sexes; apex of fifth ventrite without triangularly bulged projection at apex in both sexes; aedeagus (Fig. 7a) with parameres slightly shorter than phallobase, sinuately widened and bearing long setae at apex; median lobe widest at midlegth, narrowing to very finely truncate apex, without spines. For complete description see Smetana (1978).

Cercyon floridanus  is part of the C. tristis  group according to Smetana (1978) It resembles members of the C. gimmeli  species group, C. sklodowskae  sp. n. and C. praetextatus  . Besides of the features of the aedeagus (Fig. 7 a–c), it can be easily distinguished from them by the distinctly by the smallersize (2.35-2.70 mm), wider mesoventral plate (1.9 × as long as wide in C. floridanus  , 3.3 –5.8× as long as wide in the other species). Besides that, females of C. floridanus  lack the triangular projection on the apex of the fifth abdominal ventrite (present in C. sklodowskae  ), has a very small process of mid-prosternal ridge (large in C. gimmeli  species group), and almost straight metatibia (curved in C. gimmeli  species group).


Cercyon floridanus  is distributed in the southeastern USA, mainly in Florida, but rare records are also known from Georgia, Louisiana and Mississippi ( Smetana 1978). In the Greater Antilles it is only known from Cayman Islands, from where it was first reported by Thomas et al. (2013) under the name " C. floridanuus  Smetana" (Fig. 16a).