Nigidius dawnae Gravely 1915: 427

Paulsen, M. J., 2018, Revision of the obesus species group of the stag beetle genus Nigidius MacLeay (Coleoptera: Lucanidae: Lucaninae: Figulini), Insecta Mundi 2018 (624), pp. 1-13 : 7-9

Nigidius dawnae Gravely 1915: 427

Nigidius larssoni de Lisle 1973: 797 , new synonymy.

Type material. Male* lectotype of Nigidius dawnae ( NHM; Fig. 4 ) labeled: a) red-bordered circular “Type”; b) “ Misty Hollow , / W. side of / Dawna Hills / c. 2200 ft. / 22-30.XI.11. / (along right margin) F.H. Gravely ”; c) “ Andrewes / Bequest. / B.M. 1922-221”; d) handwritten “ Nigidius (male symbol) / dawnae Gravely ”; e) “ BMNH (E) / #607167”. Female paralectotype ( NHM) labeled: a) yellow-bordered circular “Co- / type”; b) “ Misty Hollow / to Sukli / 2100-2500 ft. / 22-29.XI.11. / (along right margin) F.H. Gravely ”; c) as type; d) as type, except (female symbol); e) “BMNH(E) / #607168”. Male paralectotype ( NHM) labeled: a) green-bordered circular “Co- / type”; b) as type; c) as type; d) as type above, except (female symbol) [sic]; e) “BMNH(E) / #607169” . Type locality: “Lower Burma … - near Misty Hollow and Sukli ”. [*The 15 mm lectotype was not dissected to determine sex, but the shape of the basal mandibular tooth is consistent with a moderately sized male.]

Holotype female of Nigidius larssoni ( ZMUC) labeled: a) “ Zoologisk Museum , København. / Loc. [Doi Sutep, N. Thailand / 1100 m] / Dat.: [17-6-1958] / Leg.: [B. Degenbøl] / Det. [Pr. 492] Journ. [4259]”; b) “[Holotypus / Nigidius / larssoni ] / M.O. de Lisle det. 197[2]”; c) red paper, “TYPE”; d) “zmuc / 00020974”; e) “ Nigidius / dawnae / Gravely / det. M.J. Paulsen 2015”. Type locality: “Doi Sutep, N. Thailand ”.

Additional material examined ( Fig. 14 ). LAOS: OUDOMXAY: Ban Tong (7, CASC) . MYANMAR: KAYIN: Dawna Hills (2, MJPC ). THAILAND: CHIANG MAI: Chiang Dao (1, MJPC). CHIANG RAI: Wiang Pa Pao (2, MJPC). KANCHANABURI: Thong Pha Phoom/Phu Yae (1, MJPC). TAK: Umphang Village (450, NHM).

Diagnosis. Nigidius dawnae has male genitalia that are most similar to N. obesus , with a sinuous flagellum bearing a small lobe near the apex ( Fig. 11 ). The flagellum is unique in having a greatly reduced lateral area that is enlarged in the remaining species (forming a large, lateral lobe in the Indonesian species). The elytral intervals are more irregularly punctate than in N. obesus , and the basal mandibular tooth of males is much broader than in N. obesus .

Remarks. The distribution of N. dawnae specimens examined is shown in Fig. 14 . Gravely’s concept of Tenasserim included the Dawna Hills, so it cannot be assumed that the specimen labeled simply “Tenasserim” is from Tanintharyi state farther south, which is the current, more restricted interpretation of Tenasserim. A small series of N. dawnae from CASC are labeled as being from Ban Tong, Laos. A cursory general search online for the locality resulted in eleven such place-names. Burton (1978) attempted to reconcile the labels of the collector in question, Vitalis de Salvaza, which he noted were overly specific to localized place-names and for the most part untraceable. He indicated that de Salvaza collected in Panghai, Laos on 8.v.1920, which is about one month after the Ban Tong specimens’ date of 9.iv.1920. Panghai is in Sainyabuli province less than 14 km from Chiang Rai province of Thailand, where N. dawnae is known to occur. A further complication is that Beuk (1999) lists a BMNH specimen label of “ Thailand, Ban Tong, 9.iv.1920, R. V. de Salvaza”, giving the exact date but with a different country, perhaps due to the differently defined boundaries of the time. I have found no other instance of a Vitalis de Salvaza label attributed to Thailand, and he seems to have collected most frequently in present-day Laos. The most likely Ban Tong locality is at 19°57′53″N, 100°57′18″E, in Oudomxay Province not far removed (~ 45 km) from Chiang Rai, Thailand or Panghai, Laos. This locality has been indicated on the map with a question mark. Regardless, the specimens from Laos constitute a new country record. Specimens examined are from April – July and December.

Figures

Figure 14. Distribution of obesus group species: N. obesus (triangles), N. dawnae (squares), N. gravelyi Paulsen, n. sp. (diamonds), N. helleri (circles).

Figures 3–4. Nigidius dawnae Gravely. 3) Major male, dorsal habitus. 4) Lectotype male with labels.

Figures 10–13. Male genitalia of obesus group species. 10) N. obesus. 11) N. dawnae, arrow indicates small apical lobe. 12) N. gravelyi Paulsen, n. sp. 13) N. helleri, arrow indicates large lateral lobe.