Cronion Bergroth, 1891

Rédei, Dávid, 2017, Taxonomic corrections on Cronion (Hemiptera: Heteroptera: Plataspidae), Zootaxa 4362 (4), pp. 584-588 : 584-585

Cronion Bergroth, 1891

Poseidon Vollenhoven, 1864: 30 . Type species by monotypy: Poseidon malayanus Vollenhoven, 1865 . Junior homonym of Poseidon Girard, 1852 (Nemertea).

Cronion Bergroth, 1891: 214 . New name for Poseidon Vollenhoven, 1864 .

Triodocoris Miller, 1955: 579 . Type species by original designation: Triodocoris cinctus Miller, 1955 (= Poseidon malayanus Vollenhoven, 1864 ). New subjective synonym.

Poseidon : Vollenhoven (1865: 63) (intended original description), Stål (1876: 6) (catalogue), Atkinson (1887: 25) (English translation of original description), Lethierry & Severin (1893: 3) (catalogue).

Cronion : Kirkaldy (1909: 322, 373) (catalogue).

Diagnosis. Medium-sized (10–15 mm) plataspids with weakly convex dorsum and flat venter; head strongly broadened and flattened, interocellar distance much shorter than distance between ocellus and ipsilateral eye, shape strikingly sexually dimorphic: mandibular plates forming a pair of long, anteriorly directed horn-like anteocular processes laterally and a pair of elongate, porrect processes submedially, submedian processes long adjacent anteriad of clypeus and together form a long, porrect projection in the midline (³), or simple, spade-shaped, with mandibular plates narrowly adjacent anteriad of clypeus (♀); antennal insertions far removed from eye, situated at about equal distance from eye and buccula. The unique, peculiarly modified head of the male is diagnostic for this genus.

Diversity and distribution. The single included species occurs in the Malay Peninsula.

Remarks. The preliminary report on Poseidon and Poseidon (now Cronion) malayanus ( Vollenhoven 1864) is very short, but still it contains a few remarks on diagnostic characters (“drietandige kop” = tripartite head) purported to differentiate Poseidon from related genera, therefore it is accepted as satisfying the criteria of availability for names published before 1931 ( ICZN 1999, Art. 12) and it is recognized as the first work to publish these names in an available way.

The subjective synonymy of Poseidon (now Cronion) malayanus , the type species of Poseidon by monotypy and of Cronion by an objective synonymy with Poseidon , and Triodocoris cinctus , the type species of Triodocoris by original designation, as proposed below, renders Triodocoris as a subjective junior synonym of both Poseidon and Cronion .

Taxonomic placement. The phylogeny of Plataspidae is unresolved, no higher classification universally applicable for the world fauna exists, and nearly half of the described genera have never been or cannot be placed into any of the two formally proposed subfamilies ( Rider et al. 2017). Cronion has also remained unplaced within Plataspidae . The combination of a weakly convex dorsum, flat venter, ventrally directed posterior aperture of genital capsule (³) and ovipositor (♀), the greatly broadened head with small, transverse eyes placed strongly laterally, ocelli far removed from the mesal margins of the compound eyes, and antennal insertion placed far from the compound eyes make it evident that Cronion is closely related to Brachyplatys Boisduval, 1835 , therefore it is formally placed into the subfamily Plataspinae in a narrow sense, corresponding with the Brachyplatys group of authors ( Jessop 1983, Rider et al. 2017).