Dacus (Mellesis) danumensis Doorenweerd, 2025

Doorenweerd, Camiel, Chung, Arthur Y. C., Mustapeng, Andi Maryani A. & Rubinoff, Daniel, 2025, The Dacini fruit flies of Borneo: an annotated checklist with 89 species including three new to science (Tephritidae, Dacinae), ZooKeys 1240, pp. 305-325 : 305-325

Dacus (Mellesis) danumensis Doorenweerd sp. nov.

Fig. 4

Type material.

Holotype. Male. “ Malaysia: Sabah: Danum valley Tembaling waterfall trail . WGS 84 4.9534, 117.8062 3–5. xii. 2018 Zingerone trap. Leg. D. Rubinoff & C. Doorenweerd. DNA sample ms 08931. ” Deposited at the University of Hawaii Insect Museum reg. no. UHIM.ms 08931 .

Differential diagnosis.

The combination of an elongate and petiolate (‘ wasp-like’) abdomen, a uniquely shaped postsutural medial yellow vitta that is almost equally wide as long, the wing with a costal band that reaches up to vein R 4 + 5 and does not expand apically, and the absence of an anal streak, is unique within Dacini . The most closely related species based on COI sequence data is Dacus sinensis Wang , from which D. danumensis can be morphologically distinguished by having a medial postsutural yellow vitta, which is absent in D. sinensis .

Molecular diagnostics.

Dacus danumensis COI - 5 P 3 P sequences are most similar to sequences of D. sinensis at 8.6 % minimum pairwise difference ( Doorenweerd et al. 2024 b).

Description.

Male. Head (Fig. 4 B ). Fulvous with two waterdrop-shaped black facial spots in the antennal furrows and a black band connecting both compound eyes across the occiput. Antennae dark fulvous. Combined length of antennal segments greater than the height of the head Thorax (Fig. 4 A, C ). Scutum and pleural areas completely black. Yellow markings: postpronotal lobes; notopleura and adjacent presutural area; medial postsutural roughly waterdrop-shaped vitta; mesopleural stripe approx. the width of the notopleuron, anterior margin slightly convex; anatergite, katatergite; scutellum. Setae: one pair scutellar; prescutellar setae absent; one pair intra-alar; one pair posterior supra-alar; one pair anterior supra-alar; two pair notopleural; four scapular. Abdomen (Fig. 4 A, C, D, F ). Abdomen shape petiolate with narrow and elongated segment I; terga fused; pecten present on tergum III; posterior lobe of the male surstylus short (Fig. 4 F ); abdominal sternum V with a narrow concavity on the posterior margin. Tergum I black with yellow posterior band; tergum II yellow with a black T-shape; tergum III with a second black T-shape that covers most of the segment and a medial black line that continuous from tergum II down to the posterior of tergum V; lateral black bands on tergum IV and V. Ceromata yellow and indistinct. Legs (Fig. 4 C ). Fore tibia with dark mark on the outer surface that covers most of the tibial length; mid tibia with dark marks on the outer and inner surface that extend from one-third the distal end; hind tibia with distal quarter black. All other leg segments yellow to fulvous. Wings (Fig. 4 E ). Wing length 4.9 mm. Cells bc and c clear, faint tint in cell sc. Costal band reaches up to vein R 4 + 5, slightly crosses R 4 + 5 apically. Anal streak absent, supernumerary lobe not pronounced. Female. Unknown.

Male lure. Zingerone.

Host plant.

Unknown.

Etymology.

The species epithet danumensis is a noun in apposition that refers to the type locality; the Danum Valley Conservation Area in Sabah, Malaysia.

Comments.

This species was included as ‘ Dacus spnMalaysia 01 ’ in the DNA barcoding study of Doorenweerd et al. (2024 b). Placement in subgenus Mellesis is based on lacking prescutellar setae, a slight concavity on the posterior margin of sternum V and its elongate and petiolate abdomen shape.

Figures

Figure 4. Holotype male of Dacus danumensis sp. n., UHIM. ms 08931 A dorsal view B anterior view of the head C lateral view D dorso-anterior view of the abdomen showing the ceromata E right wing, dissected and slide mounted F detail image of the genitalia showing the surstylus length.