Homalictus atritergus, Dorey & Schwarz & Stevens, 2019

Dorey, James B., Schwarz, Michael P. & Stevens, Mark I., 2019, Review of the bee genus Homalictus Cockerell (Hymenoptera: Halictidae) from Fiji with description of nine new species, Zootaxa 4674 (1), pp. 1-46 : 18-21

Homalictus atritergus sp. nov.

( Figs 11–12 )

Material examined. Holotype ♂: 17FJ140 (SAMA 32-036172), 17/4/17, 10:45 AM, 1,328 m asl, -17.614762, 178.018284, JB Biddle, JB Dorey, CS Matthews & RK Schober, peak of Mt. Tomanivi , general sweep of grasses and flowers.

Allotype ♀: 17FJ135 (SAMA 32-036173), Mt. Tomanivi , Fiji, -17.614762, 178.018284, 17.04.2017, 10:45 AM, 1,328 m asl, JB Dorey, JB Biddle, CS Matthews, RS Schober, HG 17JB33, peak of Mt. Tomanivi, cleared patch of grass, no flowers, general sweep, sunny, light breeze.

Paratypes 2 ♂: 17FJ133 (SAMA 32-036174), 17/4/17, 10:45 AM, 1,328 m asl, -17.614762, 178.018284, JB Biddle, JB Dorey, CS Matthews & RK Schober, peak of Mt. Tomanivi , cleared patch of grass, no flowers, general sweep, sunny, light breeze . 17FJ148 (SAMA 32-036175), 17/4/17, 10:45 AM, 1,328 m asl, -17.614762, 178.018284, JB Biddle, JB Dorey, CS Matthews & RK Schober, cleared patch of grass with no flowers at top of Mt. Tomanivi, sunny and a light breeze. General sweep of grasses and flowers; and 2 ♀, 17FJ125 (SAMA 32-036176) and 17FJ126 (SAMA 32-036177), 17/4/17, 10:45 AM, 1,328 m asl, -17.614762, 178.018284, JB Biddle, JB Dorey, CS Matthews & RK Schober, cleared patch of grass with no flowers at top of Mt. Tomanivi , sunny and a light breeze. General sweep of grasses and flowers .

Other material examined. 1 ♂: 17FJ105, 18/4/17, 12:31 PM, 1,289 m asl, -17.615347, 178.017228, JB Bid- dle, JB Dorey & RK Schober, Mt. Tomanivi ; open area along ridge between peaks, sun out, low wind, clear weather grassy open area . 2 ♀: 17FJ98 and 17FJ99, 18/4/17, 12:31 PM, 1,289 m asl, -17.615347, 178.017228, JB Biddle, JB Dorey & RK Schober, Mt. Tomanivi ; open area along ridge between peaks, sun out, low wind, clear weather grassy open area .

Diagnosis. Males: Supraclypeal area mostly finely colliculate ( Fig. 1 f-g) and T1 black or nearly so ( Fig. 11 ac).

Females: In combination: Supraclypeal area mostly finely colliculate ( Fig. 1 f–g), scutum reddish, posterior margin of scutum abought straight, pygidial plate smooth ( Fig. 11j ) and posterior margin of propodeum does not form a triangular pattern ( Fig. 11f ).

Description. Males: Measurements: UID 0.7–0.88 mm. LID 0.55–0.69 mm. AOD 0.2–0.5 mm. IAD 0.12–0.16 mm. OAD 0.36–0.44 mm. IOD 0.2–0.27 mm. OOD 0.21–2.7 mm. GW 0.22–0.25 mm. EW 0.3–0.39 mm. BL 4.1–4.7 mm. ML 0.09–0.13 mm. SL 0.21–0.26 mm. FL 4.18–4.23 mm.

Colouration: Clypeus golden green and metallic can be partly iridescent. Supraclypeal area golden green and metallic. Frons golden. Paraocular area golden green and metallic can be partly iridescent. Scutum golden green and metallic, can have some orange and appear reddish. Scutellum and propodeum dorsally golden green and metallic. Metasoma T1 black or nearly so, T2 onwards dark green or green, dark along posterior edges.

Sculpturing: Paraocular area colliculate, longitudinal striae posteriorly and proximally above antennal socket. Frons longitudinal and rarely diagonal striae posteriorly and anterior striae messy. Supraclypeal area mostly finely colliculate. Clypeus finely colliculate. Vertex punctures fine, close and sparse. Scutum anteriorly and posteriorly finely or moderately colliculate; medially finely colliculate. Scutellum punctation open and sparse. Propodeum; dorsally strong striae, weak medial anterior groove coarsely strigate-rugose; laterally fine to moderately colliculate and some striae anteriorly, dorsally and can meet; posteriorly finely colliculate, transverse striae medially and ventrally and proximally.

Morphology: Scape extends to or below anterior margin of medial ocellus. Interantennal distance about equal to diameter of socket. Labrum simple. Clypeus not depressed medially. Area posterior of vertex with strong and close striae. Posterior margin of Scutum shape mostly straight or convex. Gonostylus short and broad, dorsoapical crest of gonocoxite moderate with proximal hooks.

Females: Measurements: UID 0.73–0.77 mm. LID 0.72–0.74 mm. AOD 0.25–0.26 mm. IAD 0.11– 0.11 mm. OAD 0.41–0.49 mm. IOD 0.18–0.21 mm. OOD 0.2–0.22 mm. GW 0.24–0.33 mm. EW 0.32–0.4 mm. BL 5.55–6.48 mm. ML 0.14–0.16 mm. SL 0.3–0.36 mm. FL 4.37–4.63 mm.

Colouration: Clypeus anteriorly black; posteriorly golden green and metallic. Whole clypeus partly iridescent. Supraclypeal area, frons, paraocular area golden green and metallic. Scutum golden green and metallic, partly metallic orange and pink, and can appear reddish. Scutellum golden green and metallic, can be golden, partly metallic orange, pink pink or blue. Propodeum dorsally golden green and metallic. Metasoma T1 black or nearly so, T2 onwards black to dark green, dark along posterior edges and some iridescent purple.

Sculpturing: Paraocular area some messy striae below antennal sockets and colliculate, longitudinal striae posteriorly and proximally above antennal socket. Frons mostly longitudinal striae and anterior striae messy. Supraclypeal area mostly finely colliculate, rarely some messy striae posteriorly. Clypeus finely colliculate. Vertex punctures fine and close, open and/or sparse and rarely minute and open. Scutum anteriorly finely colliculate and lineolate; medially and posteriorly finely colliculate. Scutellum punctation close and open. Propodeum; dorsally linear pattern present or absent, some posterior transverse striae, weak medial anterior groove and coarsely strigaterugose; laterally finely colliculate, some striae anteriorly and dorsally and some striae ventrally; posteriorly finely colliculate, transverse striae dorsally, medially and ventrally and proximally and striae originating ventrally and medially almost forms circles with dorsal striae. Pygidial plate open fine punctures medially and few minute sparse punctures.

Morphology: Scape extends to above vertex. Interantennal distance about equal to diameter of socket. Labrum with two medial projections parallel from one another. Clypeus not depressed medially. Area posterior of vertex with strong and close striae. Posterior margin of scutum shape mostly straight.

Comments. Given the very limited geographical and elevational distribution of H. atritergus it is likely to be threatened by future climate warming.

Distribution. Homalictus atritergus has only been sampled from Mt. Tomanivi on the largest island, Viti Levu ( Fig. 12 ). Collections of H. atritergus have only been made between 1,289 m asl and 1,328 m asl, and the latter is the highest elevation in Fiji.

Etymology. T1 of both males and females of H. atritergus are black. The name H. atritergus is derived from the Latin adjective atri meaning ‘dark’ (genitive case of ‘ater’) and the noun tergus meaning ‘back’ or ‘rear’.

Figures

FIGURE 1. Propodeum dorsally showing (a) coarsely, (b) moderately and (c) finely strigate-rugose sculpturing. Fovea along anterior inner margin of eye (d) present and (h) absent. Supraclypeal area showing (e) mostly moderately, (f) mostly finely and (g) entirely finely sculpturing.

FIGURE 11. Homalictus atritergus sp. nov. male (a) dorsal habitus, (b) lateral habitus, (c) dorso posterior, (d) anteriorly frontal face and (e) ventral genitalia. Female (f) dorsal habitus, (g) lateral habitus, (h) dorso posterior, (i) anteriorly frontal face and (j) pygidial plate.

FIGURE 12. Collection map of Homalictus atritergus sp. nov. from specimens with identity confirmed by mtDNA COI gene. Sample size is 17.