Psenulus gibbus, Taylor & Barthélémy & Chi & Guénard, 2020

Taylor, Christopher K., Barthelemy, Christophe, Chi, Roy Cheung Shun & Guenard, Benoit, 2020, Review of Psenulus species (Hymenoptera, Psenidae) in the Hong Kong SAR, with description of three new species, Journal of Hymenoptera Research 79, pp. 169-211 : 169

publication ID	https://dx.doi.org/10.3897/jhr.79.55832
publication LSID	lsid:zoobank.org:pub:9AF2643B-484E-4367-845E-20772317FCFF
persistent identifier	https://treatment.plazi.org/id/D331DAB3-DF24-494C-95A7-8B5E8E003FF6
taxon LSID	lsid:zoobank.org:act:D331DAB3-DF24-494C-95A7-8B5E8E003FF6
treatment provided by	Journal of Hymenoptera Research by Pensoft
scientific name	Psenulus gibbus
status	sp. nov.

Treatment

Psenulus gibbus sp. nov.

Figs 4D-4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11 , 12 View Figure 12 , 13 View Figure 13 , 14 View Figure 14 , 15 View Figure 15 , 16 View Figure 16 , 17D View Figure 17 , 18G, H View Figure 18 , 19G, H View Figure 19 , 20D View Figure 20 , 21D View Figure 21

Diagnosis.

Based on a dorsally broadened interantennal carina (Figs 6D View Figure 6 , 7D View Figure 7 ), bidentate clypeus (Figs 20D View Figure 20 , 21D View Figure 21 ), short prescutal sutures (Figs 10D View Figure 10 , 11D View Figure 11 ), hind tibia lacking basal spines (Figs 18G View Figure 18 , 19G View Figure 19 ), and a well-defined pygidial plate, this species may be placed in the P. quadridentatus species group of van Lith (1962). The specimen resembles Psenulus compactus van Lith, 1962 (from Sumatra) but differs in the broadened excavation of the interantennal carina being less extensive (not extending below the antennal sockets), the subantennal carina being absent, and the mesosoma being less densely punctate. Psenulus gibbus sp. nov., superficially resembles P. ephippius sp. nov. but is readily differentiated by the yellow legs (Figs 4D View Figure 4 , 5D View Figure 5 ) and the reticulate dorsal surface of the propodeum (Figs 14D View Figure 14 , 15D View Figure 15 ) in the former and dark/brown legs (Figs 4C View Figure 4 , 5C View Figure 5 ) and polished dorsal surface of the propodeum (Figs 14C View Figure 14 , 15C View Figure 15 ) in the latter.

Material examined.

Holotype: China, Hong Kong • ♀; Mang Kung Wo ; 22°22'06"N, 114°15'12"E; 60 m a.s.l.; 23 Mar.-06 Apr. 2018; C. Barthélémy leg.; Malaise trap, ref.: M405CHy4; CAS GoogleMaps . Paratypes: China, Hong Kong • 1 ♀; ibid.; 11-25 Apr. 2020; ibid; ref.: M483CHy2; CBC GoogleMaps • 1 ♀; ibid.; 25 Apr. 2020 - 09 May 2020; ibid; ref.: M485CHy5 GoogleMaps • 2♀ 4♂; ibid.; 09 Mar. 2020; same collector; hand net, refs: 0708AHy1, 0708AHy2A, 2B and 2C; CAS and CBC GoogleMaps • 1 ♀; ibid.; 10 Mar. 2020; ibid.; ref.: 0709AHy1; CBC GoogleMaps • 1♀ 1♂; ibid.; 13 Mar. 2020; ibid..; refs: 0710AHy1 and 0710AHy2; CBC GoogleMaps .

Standard ratios.

Male (n = 4): L = 5.9-6.9 mm (mean = 6.3 mm); CR = 1.24-1.27 (mean = 1.26); OOR = 0.48-0.76 (mean = 0.64); FLR = 1.08-1.19 (mean = 1.14); FRR = 0.66-0.74 (mean = 0.71); MR = 1.41-1.59 (mean = 1.50); OMR = 0.82-0.92 (mean = 0.88); PR = 0.35-0.62 (mean = 0.49); PFR = 1.15-1.30 (mean = 1.20). Female (n = 6): L = 6.8-8.4 mm (mean = 7.55 mm); CR = 1.32-1.4 (mean = 1.36); OOR = 0.62-0.75 (mean = 0.67); FLR = 1.28-1.57 (mean = 1.44); FRR = 0.65-0.79 (mean = 0.73); MR = 1.30-1.64 (mean = 1.44); OMR = 0.82-0.93 (mean = 0.86); PR = 0.4-0.88 (mean = 0.66); PFR = 1.13-1.28 (mean = 1.18).

Description.

Male: Antenna with tyloids on F1 to F11. Ventral margin of clypeus with two rounded teeth separated by a rounded emargination (Fig. 21D View Figure 21 ), remainder of the ventral margin straight for half of width, terminated on last third with a rounded lobe intersecting eye margin; dorsal margin concave on the central third of transverse width of clypeus, remainder reaching ventral margin along a shallow convex line. Subantennal carina well developed nearly reaching toruli (Fig. 7D View Figure 7 ); interantennal carina dorsally moderately broadened and slightly excavated on its basal part only (Fig. 9D View Figure 9 ). Mesosoma with very small largely interspaced punctures bearing numerous long and fine appressed setae; mesoscutum with the same texture (Fig. 11D View Figure 11 ); prescutal sutures extending beyond anterior level of tegula; episternal sulcus broadly foveolate (Fig. 13D View Figure 13 ), mesopleural suture simple; propodeal enclosure well defined with large fovea (Fig. 15D View Figure 15 ). Propodeum laterally and posteriorly weakly reticulate with long appressed setae, dorsal half polished with very small and largely interspaced punctures (Fig. 15D View Figure 15 ). Petiole subcylindrical, T1 low (Fig. 5D View Figure 5 ). Hind tibia without denticles dorsobasally (Fig. 19G View Figure 19 ). Pygidial plate simple (Fig. 17D View Figure 17 ). Fore wing (Fig. 19H View Figure 19 ) with first recurrent vein more or less interstitial with first and second submarginal cells, second recurrent vein meeting third submarginal cell at about 1/5 (0.18 ×) of cell length from base.

Head entirely black with appressed silvery pubescence (Figs 7D View Figure 7 , 9D View Figure 9 ); antenna with scape mostly yellow, venter of pedicel and venter of flagellum of a lighter brown, dorsum of pedicel and remainder of flagellum dark brown; mandible black on the apical third, the remainder yellow. Mesosoma entirely black (Fig. 7D View Figure 7 ) but pronotal lobe and tegulae dark yellow/red. Trochanter, femurs, tibiae and tarsus yellow/orange, coxae black. Petiole black, remainder of metasoma mostly reddish but T2-T5 and S3-S7 with large dark brown/black areas (Fig. 7D View Figure 7 ).

Female: Ventral margin of clypeus with two relatively sharp teeth separated by a sub-triangular emargination (Fig. 20D View Figure 20 ), remainder of the ventral margin straight for half of width, terminated on last third with a blunt lobe intersecting eye margin; dorsal margin flattened for central third of transverse width of clypeus, remainder reaching ventral margin along a shallow convex line. Subantennal carina absent (Fig. 6D View Figure 6 ); interantennal carina dorsally broadened and deeply excavated (Fig. 8D View Figure 8 ); Mesosoma with very small largely interspaced punctures bearing numerous long and fine appressed setae; mesoscutum with the same texture (Fig. 11D View Figure 11 ); prescutal sutures short, not extending beyond anterior level of tegula (Fig. 10D View Figure 10 ) episternal sulcus broadly foveolate (Fig. 13D View Figure 13 ), mesopleural suture simple; propodeal enclosure well defined with large fovea (Fig. 15D View Figure 15 ). Propodeum laterally and posteriorly weakly reticulate with long appressed setae, dorsal half polished with very small and largely interspaced punctures (Fig. 15D View Figure 15 ). Hind tibia with a cluster of 7-9 short brown denticles dorsobasally, but no spines (Fig. 18G View Figure 18 ). Petiole subcylindrical, T1 low (Fig. 5D View Figure 5 ). Pygidial plate with faint ventrolateral carinae extended basally (Fig. 16D View Figure 16 ). Fore wing (Fig. 18H View Figure 18 ) with second recurrent vein meeting third submarginal cell at about 1/5 (0.22 ×) of cell length from base.

Etymology.

Specific name derived from the prominent hump [= Psenulus gibbus in Latin] formed by the interantennal ridge, extending below the antennal sockets and ending at middle of toruli.

Notes.

By its marked differences with the other known Psenulus of similar coloration as detailed in the diagnosis section, we have concluded that this is in fact a new species to science.

The first collection of this species occurred in 2019 and thus far the distribution of this species is limited to a single location in Mang Kung Wo, which is the sampled site with the highest anthropogenic disturbance. In March 2020 a series of seven specimens (four males and three females) were collected by hand net. Nonetheless, this species is one of the least common Psenulus encountered in Hong Kong. With the limitations presented above, knowledge about its activity period is limited to March (W11-W13) and April (W15-W17).