Monday, February 24, 2025

[Entomology • 2025] Dichodontus fluctus • A remarkable New Species of the Genus Dichodontus Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae) from Thailand and Myanmar, with Discussions on Some Sundaic Species


Dichodontus fluctus 
Geshev, Pathomwattananurak & Jiaranaisakul, 2025 


Highlights
• A new species of Dichodontus is described from Thailand and Myanmar.
D. punctipennis is newly recorded from Thailand, and D. grandis is newly recorded from Thailand and Myanmar.
• Rediscovery of paralectotypes of two species are provided, and type material of some species are illustration for the first time.
• Misidentification of a species is identified and discussed.

Abstract
Dichodontus fluctus Geshev, Pathomwattananurak & Jiaranaisakul, new species from Thailand and Myanmar is described and illustrated. Lectotypes and newly identified paralectotypes of Dichodontus punctipennis Arrow, 1937 and Dichodontus grandis Ritsema, 1882, as well as the holotype and a female paratype of Dichodontus crassus Silvestre, 2001 are illustrated. D. punctipennis is newly recorded from Thailand, and D. grandis is recorded from Thailand and Myanmar for the first time. Additionally, previous record of D. crassus from Thailand is discussed and omitted from the distribution.
 
Keywords: Taxonomy, New Taxa, Oryctini, Indochina, Sundaland, Oriental Region

 Habitus comparisons between Dichodontus fluctus Geshev, Pathomwattananurak & Jiaranaisakul, new species and Dichodontus punctipennis Arrow, 1937 in oblique view.
A–D, D. fluctus (A, holotype; B–D, paratypes); E–H, D. punctipennis;
A–C, E–G, male; D, H, female; Similarly-developed, same-sex individuals compared in the same row.

 Habitus of Dichodontus fluctus Geshev, Pathomwattananurak & Jiaranaisakul, new species.
A–B, holotype; C, male paratype (Myanmar);
D–E, female paratype (Thailand); F, male paratype (Thailand);
A, C, D, F, dorsal view; B, E, ventral view.

Dichodontus fluctus Geshev, Pathomwattananurak & Jiaranaisakul, new species

Etymology. This new species is named for its interesting pronotal morphology, with the thoracic hump widely and anteriorly produced and the shiny anterior depression with rather constant curvature in well-developed males forming a shape similar to a large wave together. The name “fluctus” means “wave”.

 
Georgi A. Geshev, Wuttipon Pathomwattananurak and Kawin Jiaranaisakul. 2025. A remarkable New Species of the Genus Dichodontus Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae) from Thailand and Myanmar, with Discussions on Some Sundaic Species. Journal of Asia-Pacific Entomology.  28, 102381. DOI: doi.org/10.1016/j.aspen.2025.102381