Heptodonta arrowi W. Horn, 1900

Görn, Sebastian, 2020, Revision of the Oriental tiger beetle genus Heptodonta Hope, 1838 (Coleoptera: Cicindelidae), Zootaxa 4875 (1), pp. 1-62 : 34-35

Heptodonta arrowi W. Horn, 1900

Figs. 3, 88–98, 155

Heptodonta Arrowi W. Horn, 1900: 362 .

Odontochila (“group” Heptodonta ) Arrowi. W. Horn, 1910: 204.

Heptodonta arrowi . Fowler, 1912: 313.

Odontochila (Heptodonta) Arrowi. W. Horn, 1926: 124 .

Type locality. Burma: N. Chin Hills .

Type material. Lectotype (designated here): ♂ in BMNH, labelled: “Type / H.T.” [round with red frame, printed] // “N. Chin Hills. / Burma. / 94–4.” [with yellow line, printed] // “ Heptodonta Arrowi / W. Horn” [with black line, handwritten] // “Named by / Dr. W. Horn. / G.J.A.” [printed]. Paralectotype: 1 ♂ in SDEI: “N. Chin Hills. / Burma. / 94–4.” [with yellow line, printed] // “Britisch.Mus.” [printed] // “Type! / Dr. W. Horn” [with black frame, printed] // “ Syntypus ” [red, printed] // “Coll. W. Horn / DEI Eberswalde” [printed] // “Arrowi / mihi” [yellow with black frame, handwritten] // “arrowi / Horn” [yellow with black frame, handwritten] // “SDEI Coleoptera / # 301569” [printed]. All type specimens labelled: “ LECTOTYPE (or PARALECTOTYPE respectively) / Heptodonta / Arrowi / W. Horn, 1900 / design. Sebastian Görn 2020” [red, printed] // “ Heptodonta / arrowi / W. Horn, 1900 / det. Sebastian Görn 2020” [printed].

Diagnosis. Small slender species with distinctive labral shape. Resembling H. horii sp. nov., but distinguishable by robust, blunt aedeagal apex, club-shaped spine row within aedeagal inner sac, usually laterally more dilated elytral and pronotal shape, coarser pronotal striation ( Fig. 3), and pronounced third labral teeth. There might be some confusion with exceptionally small individuals of H. pulchella , H. eugenia , or H. vermifera , but those species do not have a trapezoidal labrum and their elytra do not have slightly reduced microsculpture and dense, shallowly fused punctures, as in H. arrowi . The violet mesepisternum separates H. arrowi from H. pulchella and H. vermifera , and the dense anteapical punctures on the elytra from H. eugenia . The elytral surface resembles that of H. posticalis , but with different labral shape and total body length under 11.5 mm.

Redescription. Body size: Length 9.1–11.3 mm (without labrum), width 2.7–3.5 mm ( Figs. 88–89, 95–96).

Dorsal surface of head metallic reddish-bronze, copper or green, with extended green, yellowish or blue areas. Frons irregularly transverse grooved. Vertex with coarse wrinkled longitudinal grooves and in transition to orbital plates with coarse rather straight converging lines. Orbital plates with pronounced striae, that are wrinkled anterior, and with two setae on each side. Occiput with wrinkled transverse grooves, frequently anteromedian irregularly rugose. Genae glabrous and considerably grooved, from anterior to posterior yellow, green, blue, and violet, occasionally lacking yellow colouration. Clypeus glabrous, green and blue with some copper lustre. Labrum testaceous to dark-testaceous, frequently with a dark median colouration, with four setae, five apical teeth, and one lateral tooth on each side, male labrum trapezoidal (0.73–0.80 mm long, 1.28–1.43 mm wide, Fig. 90) with slightly reduced apical teeth, female labrum semicircular-trapezoidal (1.00– 1.13 mm long, 1.53–1.63 mm wide, Fig. 91) with three acute median teeth and slightly reduced third apical teeth. Mandibles testaceous in females and pale testaceous in males, with rufous-testaceous to dark-brown coloured teeth and female mandibular apex, male mandibles exceptionally broad. Labial and maxillary palpi testaceous, terminal palpomeres in females entirely dark-brown and in males apically or entirely dark-brown, seldom pre-terminal maxillary palpomeres dark-testaceous. Antennae slender, extending back over the first half of the elytra in males, dark-brown to metallic black, but first five antennomeres frequently dark-testaceous, scape with a single apical seta, antennomeres 3–4 with few scattered setae, antennomeres 5–11 finely and evenly pubescent, terminal antennomere occasionally dilated.

Thorax entirely glabrous. Pronotum ( Fig. 3) metallic green with expanded reddish-bronze areas on anterior lobe, posterior lobe, and disc, plus bluish-green to blue areas especially on posterior sulcus and lateral margins, approximately as long (1.78–2.15 mm) as wide (1.75–2.08 mm), narrow to moderate median line blue, coarse transverse grooves wrinkled on disc, pronounced anterior and posterior sulci, posterior lobe almost as wide as anterior, lateral margins of median lobe rather convex. Proepisternum and mesepisternum violet, metepisternum, sterna and epimera bluish-green with some greenish lustre, occasionally proepisternum and mesepisternum with blue or green lustre, or metepisternum, sterna and epimera with some violet colouration.

Elytra elongate, length 5.5–7.0 mm, slightly dilated laterally to almost parallel in males and conspicuously dilated in females, maximal width at the middle, metallic green with extended reddish-bronze central area, or less frequently metallic bluish-green with gently bronze lustre in combination with bluish areas ( Fig. 95), lateral margin violet, reduced (but still visible) microsculpture, juxtahumeral, discal, and apical impression slightly pronounced, basodiscal convexity moderate, posterior gibbosity lacking or gently pronounced, dense punctures slightly deeper anteriorly and forming shallowly fused transverse grooves.

Legs elongated, procoxae and mesocoxae testaceous with gently dark-testaceous and iridescent green colouration, metacoxae metallic blue to green and with testaceous posterior apex, pro- and mesocoxae anterior, metacoxae laterally densely covered with long white setae, mesocoxae posteriorly with few white setae. Trochanters testaceous. Femora testaceous with dark-brown distal apices, dark colouration dorsally slightly extended. Tibiae proximally testaceous and distally dark-brown. Tarsi dark-brown or dark-testaceous with dark-brown distal apex, slender. Claws testaceous.

Abdominal sternites glabrous (apart from few long setae at posterior margins), dark-brown with bluish reflections on first five sternites, occasionally with violet-golden reflections or dark-testaceous margin of anal sternite ( Fig. 92).

Aedeagus angled, length 2.18–2.33 mm, medioventrally slightly convex or straight, apex slightly pointed ventrally, blunt tip with short moderate to steep dorsal ascent, anterodorsal rather straight ascending, hump-shaped dorsal curvature peaked posteriorly, aedeagal base steeply sloping. Inner sac in right lateral aspect with rather straight apical-anteromedian spine row that is broadened anteriorly, in left lateral aspect inner sac median with diagonal, anterodorsal, wide flabellate sclerite ( Figs. 93–94).

Variability. Aedeagal apex blunt, but variable in angle. Large variation in dorsal colouration from reddishgreen to bluish-green.

Distribution. Western and central MYANMAR (Bago Region, Chin State, Magway Region, Sagaing Region).

Additional material examined. 12 specimens. MYANMAR : Magway Region, 10km W Ainggyi, Pyon Village , 30.–31.V.2018 ( JWCW, SGCH) ; Sagaing Region, Maharmyaine Wildlife Sanctuary, near Thet keg yin, Sa Yoe, 31.V.2016 ( JWCW) ; Sagaing Region, Chatthin Wildlife Sanctuary, Sanmyaung Camp , 30.V.2016 ( JWCW, SGCH) ; Sagaing Region, Maharmyaine Wildlife Sanctuary, Thek Kegyin , 6.VI.2014 ( CKCE, SMNS) ; Bago Region, Tharrawaddy ( BMNH) .

Biology. Occurs in secondary forests along hollowed paths on vertical banks ( Fig. 155).

Remarks. Only a few records are known for this species ( Horn 1900, 1910, 1926; Fowler 1912; Heynes-Wood & Dover 1928; Wiesner 1992; Cassola & Klícha 2002). While four populations of examined material are located in northwestern Myanmar, a single female was collected in the Irrawaddy Delta region. Although the coarse pronotal striation and pronounced third labral teeth indicate the correct identification of that female, the definite distribution in this region needs to be verified, due to the comparatively elongated shape of this speciemn’s labrum, pronotum, and elytra.