Haidomyrmex cerberus Dlussky, 1996

Guo, Yuanyuan, Shih, Chungkun, Zhuo, De, Ren, Dong, Zhao, Yunyun & Gao, Taiping, 2021, The first queen-worker association for Cretaceous Formicidae: the winged caste of Haidomyrmex cerberus, ZooKeys 1048, pp. 69-78 : 69

Haidomyrmex cerberus Dlussky, 1996

Figs 1 , 2 , 3

Specimens examined.

CNU-HYM-MA2015011, an alate queen, and CNU-HYM-MA2015010, a dealate queen, both housed in Capital Normal University, Beijing, (CNUB). Holotype NHM.In.20182, in Natural History Museum , London, UK.

Diagnosis.

Alate and dealate queens. Antenna with scape distinctly longer than pedicel and the two following flagellomeres combined, FII (second flagellomere) longer than each of the other flagellomeres. Labrum with two long setae curved upward. Mandibles long, internal surface of curved portion with a row of longitudinal serrations on the apical quarter; apical portion tapered to a blunt tip, external margin of apex each with a short erect and suberect seta. Maxillary palps distinctly elongate, formed of 6 segments; labial palps relatively short, formed of 4 segments. Propleuron well developed, with dorsal portion exposed and visible dorsally.

Description of alate and dealate queens.

Based on CNU-HYM-MA2015011, alate queen, with differential characters from CNU-HYM-MA2015010, dealate queen in square brackets.

Head: Vertex broad, evenly rounded, in lateral view approximately as high as long, shaped as an upside-down isosceles triangle; with sparsely thin erect setae [vertex in lateral view severely shrunken, glabrous]. No ocelli. Compound eyes situated high on head capsule, in lateral view ovoid and strongly convex [reniform and weakly convex]. Antennae inserted between compound eyes and flanking clypeal lobe, bases exposed and frontal lobes absent. Antenna geniculate, formed of 12 segments; scape ca. 8 times as long as pedicel [ca. 6 times], FI (first flagellomere) ca. 1.3 times as long as pedicel [ca. 1.2 times]; FII ca. 3 times as long as pedicel. Apex of scape slightly broadened, its margin bearing short and erect setae; FI with a long and curved seta on median ventral surface. Clypeal process a small lobe moderately protruding between bases of antennae, with short peg-like denticles above and longer, dense, stiff spine-like setae arranged in longitudinal rows on ventral half. Ventral surface of clypeus with one visible pair of long, fine trigger hairs [trigger hairs invisible]. Labrum with two long setae curved upward. Mandible long, scythe-shaped, internal surface of curved portion with 1-2 short setae near apex and a row of longitudinal serrations on apical quarter; apical portion tapered to a blunt tip, apex reaching clypeal lobe and each with one short, erect and suberect seta; ventral corner between basal and curved portion bearing a triangular blade, apparently symmetrical and with a single tooth; ventral margin of corner with sparsely fine setae from base to apex, becoming gradually shorter and thinner [with dense fine setae from base to one third of external surface of curved portion]. Maxillary palp exposed length 0.53, with 4 visible segments [length 0.86, with 6 obvious segments]. Labial palp is invisible [length 0.30, with 4 segments].

Mesosoma: Long, slender, with sparsely thin erect setae [no visible setae]. Neck narrow and short, pronounced in lateral view. Propleuron well developed and visible in lateral view. Pronotum well developed, convex in anterior two thirds, gradually flattened in posterior third, extending laterally to anterior level of procoxa. Sulcus between pronotum and propleuron and between pronotum and mesonotum present, complete. Mesoscutum shorter than pronotum, mesoscutal dorsal outline slightly convex, with parapsidal furrows converging posteriorly to reach anterior mesonotal margin. Mesoscutellum posteriorly expanded, dorsal and posterior mesoscutellar surfaces concave. Dorsal level of metanotum and propodeum nearly at same level; propodeum slightly lower in elevation and dorsal surface gradually sloping posteriorly [metanotum and propodeum gradually sloping posteriorly]. Metapleural gland opening oval-shaped, slightly depressed. Legs long. Length of procoxa: 1.24 [0.70]; mesocoxa: 1.03 [0.38]; metacoxa:1.32 [0.47]; protrochanter: 0.20 [0.17]; meso- and metatrochanters: 0.27 [0.20]; profemur: 1.65 [1.17]; meso- and metafemora: ca. 1.78 [1.40]; protibia: 1.23 [0.94]; mesotibia: 1.32 [1.25]; metatibia: 1.92 [1.47]. Protibia apex with one large pectinate spur and two short spine-like setae, pecten of probasitarsus with fine hairs of uniform length. Mesotibia with two simple spurs, metatibia with one large pectinate spur and one short simple spur. Protarsus length 1.80 [1.40]; mesotarsus incompletely preserved, part of tarsomeres absent [complete, length 2.09]; metatarsus length 2.65 [2.55]. Ventral surface of tarsomeres with fine setulae and apex of tarsomeres I-V with two pairs of fine, long setae. Pretarsal claws with distinct subapical teeth; arolium small.

Metasoma: Petiole ca. 2.5 times as long as height [ca. 2.2 times], petiolar tergite a broadly convex node, with anterior surface approximately twice as long as posterior surface, with short anterior peduncle; small subpetiolar process projecting ventrally as a small triangle. Gaster with five segments, gastral segments I and II (abdominal segments III and IV) ca. 0.50 of total gaster length. Pygidium and hypopygium setulose. Sting very well developed.

Right forewing: Venation almost complete, anterior margin slightly folded. Cell 1R1C/SMC1 hexagonal; cell 1MC/DC1 with five sides, Rsf2 and Rsf3 distinguished, Rsf4 very short, almost as long as Mf2; (M+Cu)1 branched into (M+Cu)2 and cu-a; (M+Cu)2 short, nearly half of Rsf1; Rs+M almost as long as Mf1 and almost parallel to Cuf1; Mf2 present to juncture of Rs+M and 1m-cu; cross-vein 2rs-m slightly oblique. Nearly whole right hind wing folded over itself. (M+Cu)2 nearly as long as cross-vein cu-a; Mf1 aligned with Mf2 [wings not preserved].

Measurements

(in mm). (CNU-HYM-MA2015011, alate queen), [CNU-HYM-MA2015010, dealate queen]. BL (7.75) [6.31]; HL (1.15) [1.17]; Hh (1.24) [0.96]; EL (0.24) [0.28]; length of antennomeres (total 4.41, scape 1.12, pedicel 0.13, FI 0.18, FII 0.39, FIII 0.34, FIV 0.33, FV 0.31, FVI 0.32, FVII 0.34, FVIII 0.33, FIX 0.29, FX 0.30) [total 3.91, scape 0.75, pedicel 0.12, FI 0.15, FII 0.39, FIII 0.35, FIV 0.33, FV 0.28, FVI 0.31, FVII 0.31, FVIII 0.30, FIX 0.28, FX 0.33]; ML (0.98) [0.64]; WL (3.01) [2.45]; PL (0.79) [0.51]; PH (0.31) [0.23]; GL (2.78) [2.24].

Remarks.

Assignment of these two new specimens to H. cerberus is based on most of the characters used by Barden and Grimaldi (2012) and Cao et al. (2020a). This species is most similar to H. scimitarus , but the two new specimens could be assigned to H. cerberus by having 1) a slightly longer scape, longer than the pedicel and the two following flagellomeres combined (vs. scape visibly shorter in H. scimitarus ); 2) labrum with two long setae curved upward (vs. labrum with four fine setae); 3) ventral corner of mandible between basal and curved portion with a triangular blade, apparently symmetrical and with a single tooth (vs. 3-4 fine mesal teeth on left mandible, 2-3 slightly larger teeth on right mandible); and 4) head with sparse thin and erect setae (vs. glabrous in H. scimitarus ).

Figures

Figure 1. Haidomyrmex cerberus, alate queen specimen CNU-HYM-MA 2015011 A photo of right lateral habitus B line drawing of habitus C photo of head in lateral view D photo of mesosoma in lateral view E photo of right forewing venation F line drawing of right forewing and right hind wing. Scale bars: 1 mm (A, B); 0.25 mm (C-F).

Figure 2. Haidomyrmex cerberus, dealate queen specimen CNU-HYM-MA 2015010 A photo of right lateral habitus B line drawing of habitus. Scale bars: 1 mm.

Figure 3. Haidomyrmex cerberus, specimens CNU-HYM-MA 2015010 (A-C) and CNU-HYM-MA 2015011 (D-F) A photo of left lateral habitus B photo of protibial apex and associated tarsus C photo of petiole in lateral view D photo of clypeal lobe in lateral view E photo of petiole in lateral view F photo of left lateral habitus. Scale bars: 1 mm (A, F); 0.25 mm (B-E).