Teretrius (Neoteretrius) dispar, Lackner & Vienna, 2017

Lackner, Tomáš & Vienna, Pierpaolo, 2017, Histeridae of Socotra (Coleoptera: Histeroidea), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57, pp. 55-76: 66-71

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http://doi.org/ 10.1515/aemnp-2017-0107

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scientific name

Teretrius (Neoteretrius) dispar

sp. nov.

Teretrius (Neoteretrius) dispar   sp. nov.

( Figs 24–39 View Figs 24–25 View Figs 26–31 View Figs 32–37 View Figs 38–39 )

Type material. HOLOTYPE: J, side-mounted on a triangular mounting card, genitalia extracted, dismembered and glued to the same mounting card as the specimen, with the following printed labels: ‘ YEMEN, SOCOTRA ISLAND / Aloove area , ALOOVE vill.env. / Jatropha unicostata shrubland / with Boswelia elongatatrees / 19.-20.vi.2012 / 12°31.2’N, 54°07.4’E, 221 m’; followed by: ‘SOCOTRA expedition 2012 / J. Bezděk, J. Hájek, V. Hula / P. Kment, I. Malenovský, / J. Niedobová & L. Purchart leg.’; followed by: ‘ Teretrius (Neoteretrius)   / dispar sp.nov. / HOLO- TYPE / Det. T. Lackner & P. / Vienna 2017’ (red label) ( NMPC) GoogleMaps   . PARATYPES: YEMEN: SOCOTRA: 19 JJ 16 ♀♀ and 8 unsexed spec., with the identical labels as those of holotype (5JJ 5♀♀ in TLCM, 14 JJ 11 ♀♀ in NMPC; 8 spec. in PVCV)   ; 1 J, ‘ YEMEN, SOCOTRA Island / Aloove area , HASSAN vill. env. / 12°31.2’N, 54°07.4’E, 221 m GoogleMaps   /

Jiří Hájek leg. 9.-10.xi.2010 ’ [printed] ( NMPC)   ; 3 JJ 1 ♀, ‘ YEMEN, SOCOTRA Island, / wadi Ayhaft , / 12°36.5’N, 53°58.9’E, 200 m, / L. Purchart leg., 7.-8.xi.2010 ’ [printed] ( NMPC) GoogleMaps   ; 1 J, ‘ Yemen, Soqotra Is. / 24–26/xi.2003 / WADI AYHAFT, 190m / N 12°36’38’’E 53°58’49’’ / ( GPS), David Král lgt.’ [printed]   ; followed by: ‘ YEMEN – SOQOTRA 2003 / Expedition   ; Jan Farkač , Petr Kabátek & David Král’ [printed] ( NMPC)   ; 1 J 3 ♀♀, ‘ YEMEN, SOCOTRA / Aloove area , HASSAN vill./ env. 221 m / 12°31.2’N, 54°07.4’E 9- / 10.xi. 2010 P.Hlaváč’ [printed] ( TLCM) GoogleMaps   .

Description. Body ( Figs 24–25 View Figs 24–25 ). length PEL = 2.9–3.2 mm; APW: 0.8–1.0 mm; PPW = 1.5–1.7 mm; EW = 1.6–1.8 mm; EL = 1.5–1.8 mm. Body short and stout, cylindrical, strongly convex. Cuticle black, shining, pronotum and elytra entirely punctate, punctures separated by 1–3 times their diameter. Body appendages light to chestnut brown.

Head. Frons ( Fig. 26 View Figs 26–31 ) flattened to slightly convex, punctate, punctures separated by 2–3 times their diameter; frontal and supraorbital striae absent. Clypeus flattened, broad, its punctation similar to that of frons. Labrum inwardly arcuate, with dense tuft of long amber setae; mandibles laterally expanded ( Fig. 27 View Figs 26–31 ), their dorsal surface with prominent stout projection (‘horn’), punctate. Antennal club ( Fig. 28 View Figs 26–31 ) circular, flattened, its circumference with several rows of tiny setae; rest of club asetose.

Pronotal sides parallel on their basal 5/6, thence convergent anteriorly, apical angles obtuse. Marginal pronotal stria complete, weakened behind head, laterally carinate.

Elytral epipleuron laterally with impunctate band; marginal epipleural and marginal elytral striae either absent or indiscernible. Dorsal elytral striae completely absent; elytral humeri with glabrous oval ‘mirror’; rest of elytra densely punctate.

Propygidium pentagonal, punctate; pygidium slightly convex, evenly punctate, punctures of both propygidium and pygidium similar to those of elytra, but somewhat finer.

Anterior margin of prosternum ( Fig. 29 View Figs 26–31 ) slightly inwardly arcuate; marginal prosternal stria present anteriorly, complete; lateral prosternal striae strongly carinate, apically almost reaching marginal prosternal stria. Carinal prosternal striae subparallel to slightly divergent apically, not reaching anterior margin of prosternum (stopping just short of it). Entire disc of prosternum with scattered deep punctures separated by several times their diameter.

Anterior margin of mesoventrite ( Fig. 29 View Figs 26–31 ) strongly projected; marginal mesoventral stria almost complete, not reaching mesoventral base laterally; disc of mesoventrite with sparse punctures; meso-metaventral stria absent. Metaventrite sparsely punctate, punctures most prominent along basal margin; lateral metaventral stria well developed, slightly carinate, curved outwardly and reaching mesepimeron. Metanepisternum narrow, with scattered punctures. Abdominal ventrite I without lateral striae; disc with denser and more prominent punctation than that of metaventrite.

Protibia ( Fig. 30 View Figs 26–31 ) on outer margin with approximately ten densely set denticles; denticle 2 and 3 separated by a ‘gap’; protibial spur long and thick; protibial groove deep; terminal protarsomere approximately as long as protarsomeres I–IV together. Mesotibia on outer margin with six denticles, denticles 3–6 situated atop triangular ‘teeth’; metatibia ( Fig. 31 View Figs 26–31 ) longer and more slender than mesotibia, outer margin adorned with three shorter, widely spaced denticles; both terminal tarsomeres approximately as long as the preceding four together.

Male genitalia. Sternite VIII ( Figs 32–34 View Figs 32–37 ) separated into two halves medially, without setae apically; tergite VIII apically outwardly arcuate, with scattered pores. Sternite IX (spiculum gastrale) in form of irregularly shaped circle ( Fig. 35 View Figs 32–37 ), tergite IX ( Figs 35–36 View Figs 32–37 ) ventrally deeply emarginate medially, dorsally separated into two halves medially; tergite X ( Figs 35–36 View Figs 32–37 ) triangular. Phallobase ( Fig. 37 View Figs 32–37 ) butterfly-shaped, situated beneath basally fused parameres; parameres ( Fig. 37 View Figs 32–37 ) separated in their apical two-thirds, their apices adorned with microscopic setae; median lobe ( Fig. 37 View Figs 32–37 ) spoon-like, long and narrow.

Variability. Elytra in several specimens dark brown.

Female. Similar to male in habitus; mandibles simple, stout. Genitalia: disc of gonocoxite ( Fig. 38 View Figs 38–39 ) densely setose; apex quadrilobed; gonostylus short, narrow, bearing two long setae apically. Median sclerite ( Fig. 38 View Figs 38–39 ) triangular, resembling bull’s skull; spermatheca ( Fig. 39 View Figs 38–39 ) globular.

Differential diagnosis. This new species is rather large for the subgenus Neoteretrius   and can be characterised by the following: mesoventrite without meso-metaventral stria, anterior margin of prosternum almost straight, weakly inwardly arcuate; carinal prosternal striae subparallel to weakly divergent anteriorly, outer margin of protibia with approximately 10 denticles. Teretrius dispar   sp. nov. can be placed in the key of BICKHARDT (1921) (the only existing key to identify the members of Teretrius Erichson, 1834   , which according to KANAAR (2008) requires revision) before species T. (N.) antelatus Lewis, 1914   from the Democratic Republic of Congo and Nigeria. Although we are not familiar with this species, it appears to differ from the newly described T. (N.) dispar   in the dorsal punctation, smaller body size, the structure of the prosternal striae, as well as in other, minor characters. However, the most distinctive character of the newly described species is found on the mandibles, which are unusually large, strongly bent, wide at base and in JJ furnished with a well developed, inwardly turned acute horn. A sexually dimorphic species, the ♀♀ are devoid of such a horn.

Etymology. The specific epithet of the new species is Latin adjective meaning ‘different’. We chose this name to point out the sexual dimorphism between the two sexes, where the male is adorned with mandibular ‘horns’ whereas the female is without them.

Collection circumstances. The specimens of the type series were mostly collected under bark of dead Boswellia elongata Balf.   f. trees (J. Hájek, pers. comm.), see also KNÍŽEK (2012a,b).

Distribution. Endemic to Socotra Island.


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