Cercyon sklodowskae, Arriaga-Varela, Emmanuel, Seidel, Matthias, Deler-Hernandez, Albert, Viktor Senderov, & Fikacek, Martin, 2017

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: 48-52

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scientific name

Cercyon sklodowskae

sp. n.

Cercyon sklodowskae  sp. n. Figures 2 a–c, 5 m–p, 10 a– 10, 1, 15c

Figures in Flickr.


Type locality.

Jamaica, Saint Thomas Parish, Corn Puss Gap, 6.44 km N of Bath. 640 m a.s.l.

Type material.

Holotype (male): "JAM., St. Thomas, Corn Puu Gap [sic!, = Corn Puss Gap], 2100', 4mi. N, Bath, 3-8.VIII.1974, S. Peck, dung" ( CNC). Paratypes: JAMAICA: St. Thomas: same data as the holotype (1 female: CNC; 1 female: NMPC); "JAM., St. Thomas, Corn Puss Gap, 2100", 4mi. N, Bath, 3.viii.74, S. Peck, DT16-20" (1 male: CNC); "JAM., St. Thomas P. Portland Gap, 5500',17.XII.72-1.I.73, S&J Peck, cloud for., dung&carrion tr." (1 male, 1 female: CNC); "JAM., St. Thomas P., Portland Gap, 17.XII.72-1.II.73, S & J Peck (1 female: CNC); "JAM., St. Thomas, below Port. Gap, 1-5.VIII.1974, 4500", S. Peck, dung trap 12" (1 female: CNC).


Cercyon sklodowskae  sp. n. can be easily differentiated from other Greater-Antilles Cercyon  species by the following combination of characters: body size 3.1-3.5 mm; dorsal surface of head black with yellowish anterolateral margins of clypeus; pronotum black with sharply defined yellowish areas at lateral margins (Fig. 2c); elytra (Fig. 2a) black, with large apical spot covering posterior third; medial ridge of prosternum anteriorly forming a small rounded to weakly pointed projection (Fig. 10c); mesoventral plate (Fig. 10f) narrow, ca. 5.8 × as long as wide; metaventrite (Fig. 10g) without femoral lines, with narrow raised pentagonal area, 1.2 × as long as wide; first abdominal ventrite without spiniform process in both sexes (Fig. 10h); apex of fifth abdominal ventrite with a triangular projection in females (Fig. 10i); aedeagus with very short parameres (Fig. 5m), median lobe (Fig. 5o) covered with spines in apical third.

C. sklodowskae  may be confused with C. praetextatus  (Say) and Cercyon floridanus  Horn and the members of C. gimmeli  species group. It can be distinguished from C. praetextatus  and C. floridanus  by the head with widely yellowish clypeal margin and yellow coloration of elytra expanded basally (clypeus black and basal part of elytra only narrowly yellow in C. praetextatus  and C. floridanus  ) and by much narrower mesoventral plate (5.8 × as long as wide in C. sklodowskae  , 1.9 × as long as wide in C. floridanus  and 3.3 × in C. praetextatus  ). It differs from members of C. gimmeli  group by the mesoventral plate reaching anterior part of metaventrite (not reaching anterior margin in C. gimmeli  group), only a small rounded process of median prosternal ridge (large rounded knob in C. gimmeli  group), straight metatibia (slightly curved outside in C. gimmeli  group), and last abdominal ventrite in females forming a triangular projection (without projection in C. gimmeli  group). It differs from all these species by the morphology of male genitalia; by the apically spinose median lobe it resembles C. armatipenis  , but differs from it by parameres much shorter than phallobase.


Body. (Fig. 2 a–c) 3.10-3.45 mm long (length of holotype: 3.29 mm); long oval, 1.8 –1.9× as long as wide, widest at basal fourth of elytra; moderately convex, 2.8 –3.0× as long as high, (height of holotype: 1.1 mm). Coloration. Dorsal surface of head blackish to pitchy black, clypeus with wide rather sharply defined yellowish area along anterolateral margins, slightly broader at sides. Ventral surface of head dark brown, almost black on sides. Antennae, mentum and mouthparts dark brown. Pronotum blackish to pitchy black, with narrowly brownish lateral margins, broader at anterolateral corners (Fig. 2c). Prosternum and hypomeron black, with darker anterolateral margins. Elytron (Fig. 2a) black, with large, pale, rather sharply defined apical spot covering posterior quarter of elytral interval 1 and gradually larger portion on subsequent intervals up to posterior three–quarters on interval 9, lateralmost interval completely yellowish to dark brown; apical spot slightly darker (yellowish-brown) posteriorly, with lighter brown spots at least along its anterior border. Ventral surface of mesothorax (Fig. 2b) blackish to pitchy black. Metepisternum dark brown. Metaventrite black with darker anteromedial part and anterior margins. Abdomen black, posteromedial margins and anterolateral corners of ventrites darker. Legs dark brown.

Head. Clypeus with moderately dense and shallow punctation consisting of crescent-shaped punctures intermixed with denser, slightly smaller and rather transverse punctures; interstices without microsculpture. Anterior margin of clypeus with a narrow bead. Frontoclypeal suture conspicuous as a zone without punctation, vanishing mesally. Frons with punctation similar to that on clypeus, punctures sparser on sides; interstices without microsculpture. Eyes rather small; interocular distance about 6 × the width of one eye in dorsal view. Labrum membranous, nearly completely concealed under clypeus, only with narrowly exposed sinuate anterior margin. Mentum (Fig. 10a) subtrapezoid, widest at posterior fourth, about 2.1 × wider than long, 1.4 × wider at widest part than at anterior margin, concave in anterior half, strongly emarginated anteromesally; surface glabrous, punctures rather small, shallow and sparse, almost vanishing anteromesally, interstices without microsculpture. Antenna with 9 antennomeres, scapus ca. 1.9 × as long antennomeres 2-6 combined; antennal club moderately elongate, about twice as long as wide, about as 1.2 × as long as scapus; antennomere 9 acuminate at apex.

Prothorax. Pronotum transverse, widest at base 2.1 –2.2× wider than long; 1.6 –1.7× wider at base than between front angles, 1.7 × wider than head including eyes, as convex as the elytra in lateral view. Punctation (Fig. 10b) moderately dense and shallow, consisting of crescent-shaped punctures intermixed with denser, slightly smaller and rather transverse punctures; punctures slightly feebler on sides. Prosternum strongly tectiform medially, medial ridge (Fig. 10c) weakly thickened anteriad, forming a small rounded to slightly pointed process. Antennal grooves distinct, with lateral margin curved, slightly feebler anteriad.

Pterothorax. Scutellar shield 1.25 × as long as wide, sparsely punctured. Elytra widest at anterior fifth, 2.7 –3.0× as long as pronotum, 1.2 × as wide as pronotum, surface (Fig. 10d) glabrous, with 10 series of punctures; series 6, 8 and 9 not reaching elytral base, serial punctures of same size in all series; intervals moderately convex; interval punctation composed by crescent-shaped punctures intermixed with denser, slightly smaller and rather transverse punctures in all intervals. Humeral bulge indistinct. Mesoventral plate (Fig. 10f) narrowly elongate, ca. 5.8 × as long as wide, widest in anterior two-fifths, more strongly narrowing towards anterior apex which is pointed, posterior tip rounded, slightly overlapping over anterior portion of metaventrite; surface with a few sparse coarse punctures. Metaventrite (Fig. 10g) with narrow raised pentagonal area, 1.2 × longer than wide, glabrous, weakly and sparsely punctuate, punctures with fine setae at least along margins of the elevation; bare elevated area reaching anterior margin of metaventrite; punctures absent at two slightly elongate areas in the center; femoral lines absent; lateral parts of metaventrite densely covered by short pubescence.

Legs. Femora with sparse rather shallow punctures ventrally, interstices with weak microsculpture consisting of longitudinal lines; tibial grooves distinct. Tibiae with rather small lateral spines. Metatibiae moderately narrow and elongate, straight, 0.3 –0.4× as long as elytra, 5.3 × as long as wide. Metatarsus long, 0.9 × as long as metatibia, with short rather stout setae ventrally.

Abdomen. With five ventrites, first abdominal ventrite (Fig. 10h) about as long as the second and third ventrites combined, with distinct median longitudinal carina narrowing posteriad, not projecting posteriorly in both sexes; fifth ventrite with acuminate apex, weakly bulged in males and with a triangularly bulged apical projection in females (Fig. 10i).

Genitalia. Sternite 9 (Fig. 5p) asymmetrical basally, median process narrow, ca. as long as lateral struts, acuminate at apex, without subapical setae. Phallobase (Fig. 5m) almost twice as long as parameres, asymmetrically narrowing at base, base narrowly rounded and hooked. Parameres continuously narrowing apically, apex pointed, with two minute setae. Median lobe (Fig. 5n) widest in apical third, slightly narrowing towards base, continuously narrowing in apical third; apex (Fig. 5o) acuminate with rounded tip, apical part with numerous spines directed backwards; gonopore moderately large, subapical; basal portion with dorsal plate narrow and simply bifid basally.


We dedicate this species to the eminent physicist and chemist Marie Skłodowska-Curie, on whose honor the Marie Skłodowska-Curie actions program of the European Union, funding this research, is named.


Jamaica: Saint Thomas (Fig. 15b).


The specimens were collected on dung and using dung and carrion-baited traps in cloud forests.