Ceroptres ensiger ( Walsh, 1864 ), 1865

Lobato-Vila, Irene & Pujade-Villar, Juli, 2019, Revision of world Ceroptresini (Hymenoptera: Cynipidae) with the description of a new genus and five new species, Zootaxa 4685 (1), pp. 1-67 : 27-28

Ceroptres ensiger ( Walsh, 1864) status verified and comb. nov.

( Figures 3h , 6 c–e)

Amblynotus ensiger Walsh, 1864 . Proc. Ent. Soc. Phila. 2: 487, 496. Type material: MCZ.

Type material (examined). LECTOTYPE (♀) with the following labels: ‘729’ (white label, handwritten) / ‘Rock Island Dr. B. D. Walsh’ (white label, handwritten) / ‘Osten-Sacken Coll.’ (white label) / ‘Type 13979’ (red label) / ‘729 Ceroptres (Amblynotus) ensiger Walsh ♀ ’ (white label, handwritten) / ‘ MCZ Image Database’ (white label) / ‘MCZ-ENT 00013979’ (white label, QR code) / ‘ Lectotype ♀ Amblynotus ensiger Walsh, 1864 , IL-V desig-2019’ (red label) / ‘ Ceroptres ensiger (Walsh) Osten-Sacken, 1865 , IL-V det. 2019’ (white label).

Diagnosis. This species can be easily separated from the rest of the Ceroptres species by having a mesopleuron that is anteriorly alutaceous ( Fig. 6d ) (mesopleuron totally smooth and shiny in the rest of species except in C. cerri , which has the mesopleuron anteriorly conspicuously striated, Fig. 11b ) and a slightly pronounced medial ridge in the depressed area delimited by the two vertical carinae on the lower face (see the diagnosis of C. cornigera ).

Redescription. Female. Length. Body length 2.5 mm (n=1).

Color ( Figs 3h , 6 c–e). Dark brown to black. Head, mesosoma and metasoma dark brown to black. Tegulae dark yellow. Hypopygium yellowish. Antennae and legs yellow (scape, pedicel and a few terminal ones brownish according to the original description), metacoxae dusky at base. Wings hyaline, veins pale.

Head. In anterior view ( Fig. 3h ) trapezoid-shaped, about 1.2 times as wide as high, genae slightly expanded behind compound eyes. Face with long and moderately dense pubescence, lower face with short striae radiating from sides of clypeus, not reaching the toruli nor the ventral margin of compound eyes; medially without striae; vertical carinae incomplete, narrow, running from inner ventral margin of the toruli 1/2 of the lower face length and delimiting a depressed area that is slightly bulged medially, forming a slightly pronounced medial ridge. Clypeus distinct, not projected over mandibles. Malar space 0.5 times as long as height of compound eye. Anterior tentorial pits visible; pleurostomal sulcus absent, epistomal sulcus slightly impressed. Transfacial line about as long as height of compound eye. Toruli situated mid-height of compound eye; distance between torulus and compound eye about as long as diameter of the toruli; distance between the toruli clearly shorter than diameter of the toruli. Front coriaceous with small scarce piliferous punctures; without frontal carinae. Head in dorsal view ( Fig. 6e ) is about 2.1 times as wide as long. Vertex coriaceous with small scarce piliferous punctures. POL:OOL:LOL = 15:6:7 and diameter of lateral ocelli, 4. Occiput coriaceous with small scarce piliferous punctures.

Antennae. 12-segmented according to the original description (the lectotype has antennae broken, Fig. 6c ); pubescence dense and short. Scape plus pedicel about 1.2 times as long as F1; pedicel 1.2 times as long as wide; F1 about as long as F2, F2 and F3 subequal. According to the original description, F10 is fully equal to F8+9 and it occasionally has indications of a connate medial suture on F10.

Mesosoma. About 1.3 times as long as high in lateral view ( Fig. 6c ), including nucha, with short and not dense pubescence. Ratio of length of pronotum medially/laterally: 0.44. Dorsal part of pronotal plate complete, with two distinct but small widely spaced foveae. Lateral pronotum alutaceous and with some weak discontinuous transversal elements, without lateral carina. Mesoscutum ( Fig. 6e ) 1.2 times as wide as long, strongly coriaceous with weak discontinuous transversal elements, somewhat punctate posteriorly; anterior grooves weakly impressed, extending at most 1/3 of the mesoscutal length. Notauli almost complete, narrow and shallow, but faint before reaching the pronotal margin. Parapsidal grooves shallow, surpassing tegulae. Median groove narrow and shallow, visible at most in the posterior 1/3 of the mesoscutum. Mesoscutellum ( Fig. 6e ) rounded, about as long as wide, densely but weakly wrinkled, more strongly wrinkled laterally and posteriorly, interspaces strongly coriaceous; circumscutellar carina absent; scutellar foveae ovate, narrow, shallow, not well defined posteriorly, weakly sculptured and separated by a narrow carina. Mesopleuron ( Fig. 6d ) almost totally smooth and shiny, but with an alutaceous sculpture anteriorly and medially; little pubescent basally. Metapleural sulcus reaching about 4/5 parts of the mesopleural height. Propodeum pubescent and smooth; propodeal carinae straight and parallel, somewhat branched posteriorly. Nucha weakly sculptured dorsally and laterally, not sulcate.

Legs. Tarsal claws bidentate, with a basal lobe.

Wings. Forewings pubescent with short marginal setae, slightly shorter than body length. Radial cell closed, almost 2.5 times as long as wide; areolet not well defined, anterior and basal veins inconspicuous. Rs+M inconspicuous. Basal cell with sparsely spaced setae.

Metasoma ( Fig. 6c ). About as long as head plus mesosoma and longer than high in lateral view. First metasomal tergum crescent-shaped and smooth. Second metasomal tergum short and free, almost 0.3 times as long as the metasomal length and with a dense hair patch anterolaterally. Third metasomal tergum without micropunctures or just with an inconspicuous posterodorsal patch, not dorsodistally incised; subsequent terga very finely punctate. Prominent part of the hypopygial spine about 2.0 times as long as wide and slightly projected.

Male. Not examined (presumably lost). According to the original description, males differ from females by measuring between 1.5–1.7 mm long and by having 15-segmented antennae, with F9–F11 subequal.

Distribution. USA. Rock Island, state of Illinois ( Walsh, 1864; Burks 1979).

Biology. Reared from leaf petiole galls of Andricus quercuspetiolicola (Bassett, 1863) on Quercus bicolor Willd. (= Q. prinus var. bicolor (Willd.) Spach 1841 ) ( Quercus section ) ( Walsh 1864).

Remarks. Amblynotus ensiger was originally described from 6♂ and 12♀ ( Walsh 1864: 497). We only located and examined 1♀ deposited in MCZ.

Amblynotus ensiger was synonymized with Ceroptres petiolicola ( Osten-Sacken, 1861) by Osten-Sacken (1865: 369). After examining the type material of both species, we conclude that they are, indeed, Ceroptres , but that they are not synonymous since they show some important morphological differences, especially regarding the number of antennal segments in females (12 in C. ensiger and 13 in C. petiolicola ) and the mesopleural sculpture (anteriorly with an alutaceous sculpture in A. ensiger and totally smooth and shiny in C. petiolicola ). In accordance with these morphological differences, we conclude that Amblynotus ensiger should be considered as a valid species within Ceroptres : Ceroptres ensiger ( Walsh, 1864) status verified and comb. nov.

Figures

FIGURE 3. Female faces of valid species of Ceroptres: a) C. catesbaei (type); b) C. cerri; c) C. clavicornis; d) C. confertus (type); e) C. cornigera (type); f) detail of the median ridge in the lower face of C. cornigera; g) head of C. cornigera in dorsal view; h) C. ensiger; i) C. frondosae (type); j) detail of the median ridge in the lower face of C. frondosae; k) head of C. frondosae in dorsal view.

FIGURE 6. a) Ceroptres cornigera lateral and b) dorsal habitus (type); c) C. ensiger lateral habitus, d) detail of mesopleuron and e) dorsal habitus (type); f) C. frondosae lateral and g) dorsal habitus (type); h) head and mesosoma of C. kovalevi in lateral view, i) lateral metasoma and j) head and mesosoma in dorsal view (type).

FIGURE 11. Ceroptres cerri a) head in anterior view, b) mesosoma in lateral view and c) metasoma in lateral view; C. clavicornis d) head in anterior view, e) mesosoma in lateral view and f) metasoma in lateral view.