Dactylispa adinae Kato, 2025

Kato, Makoto & Imada, Yume, 2025, Diversity and host plant utilization of leaf-mining beetles of Chrysomeloidea (Coleoptera) in Japan, ZooKeys 1238, pp. 209-268 : 209-268

Dactylispa adinae Kato sp. nov.

Fig. 18 I – W

Type locality.

Japan: Miyazaki Pref., Nichinan, Inohae.

Type material.

Holotype: • ♂, Inohae , Nichinan, Miyazaki Pref. (31.728°N, 131.369°E, 85 m above sea level), 18-VII-2018 (as larva on Adina pilulifera collected by M. Kato), emerged on 1-VIII-2018 ( NSMT -I-C-200360 ) . Paratypes: • 1 ♂ 2 ♀ same as holotype, emerged on 31-VII – 6-VIII-2018 ( NSMT -I-C-200361 –200363) ; 1 ♀ Kaeda-keikoku , Miyazaki, Miyazaki Pref., 11-IV-2021 (as larva on Adina pilulifera by M. Kato), emerged on 26-V-2021 ( NSMT -I-C-200365 ) .

Additional material examined.

• 1 ♂ 1 ♀ same as holotype, emerged on 3–14-VIII-2021 ; • 1 ♂ Kaeda-keikoku , Miyazaki, Miyazaki Pref., 11-IV-2021 (as larva on Adina pilulifera ), emerged on 31-V-2021 .

Diagnosis.

This newly identified species exhibits a rectangular, flattened morphology (length: 4.6–4.7 mm), characterized by black, spiny pronotum and elytra, as well as a dull yellow ventral surface. The pronotum bears a pair of dull yellow trifurcate anterior spines and three pairs of dull yellow long spines oriented horizontally. Similarly, the elytron exhibits numerous long and short spines along margins and interstices I, II, IV, VI, and VIII. The male genitalia feature an aedeagus resembling a spatula in dorsal view, appearing almost parallel-sided and uncurved in lateral view. The larvae mine the leaves of Rubiaceae , particularly Adina pilulifera . This species resembles Dactylispa nigrodiscalis Gressitt, 1938 , a Chinese species. However, it is differentiated from the latter by the widely separated anterior trifurcate spines of the prothorax and the basally separated first and second lateral spines on the prothorax.

Description.

Male (Fig. 18 I – Q ). Habitus. The body is 4.6–4.7 mm in length (excluding spines) and is mostly black on the dorsal surface and dull yellow on the ventral surface and head (Fig. 18 I, J ). The pronotum is black except for dull yellow margins, spines, and a medial linear area before the posterior margin. The elytra are largely black except for dull yellow margins in the middle.

Head. The head is broader than the anterior margin of the prothorax, narrowing behind the eyes and with a black, smooth, and shining occiput. The frons is yellowish-brown and rugose, with a small projection between antennal insertions (Fig. 18 M , arrow). The antennae are moderately long, approximately three-quarters of the body length. The segments do not feature spines and are covered with fine short hairs. Segment 1 is the longest among the 11 segments and is slightly curved outward. Segments 1 and 2 are dark brown, whereas segments 3–11 are yellowish brown. Segments 5–11 are slightly thicker than segments 3–4 (Fig. 18 I ). The proportional lengths of antennomeres 1–11 are as follows: 1: 0.3: 0.5: 0.5: 0.6: 0.6: 0.6: 0.6: 0.6: 0.6: 0.9.

Thorax. The pronotum is transverse, measuring 1.6 - fold as wide as long, with rounded sides that are prominently produced and flattened medially (Fig. 18 I ). A pair of dull yellow trifurcate spines appears at the anterior margin of the pronotum (Fig. 18 K, M ). The two anterior projections share a long common stem and point upward, whereas the posterior projection points diagonally upward and backward, with black apexes. The lateral margin of the pronotum features three long, dull yellow spines pointed horizontally, with the anterior two being longer than the posterior one and located basally on a common stem. The apexes of the anterior two projections are black (Fig. 18 N ). The base of the disc features a transverse impression. The disc is granulated and covered with large punctures between the lateral spines, with a dull yellow, impunctate, longitudinal linear depression before the posterior margin along the median line.

The scutellum is finely granulose and broad but narrow and subangulate posteriorly. The elytra are largely parallel-sided and broadly rounded posteriorly, with distinct rounded punctures on the surface (Fig. 18 I ) that are largely black. However, the lateral margins in the middle and apical regions (including spines) are dull yellow. The base of the elytron is wider than the pronotum, with the sides and disc bearing numerous long spines. The lateral margin of the elytron is flattened on each side, featuring 15 or 16 compressed spines, with alternating long and short spines. Each long spine is as long as the first segment of the antenna and slightly curved backward. The apical margin is covered with seven or eight short spines. The elytral interstices are covered with long and short spines (Fig. 18 K, O ): interspace I with two short spines, interspace II with four long spines, interspace IV with nine spines of which the fifth and seventh are long, interspace VI with nine spines of which the fifth and seventh are short, and interspace VIII with four spines of which the first and third are long. Punctuation is regular and coarse, with the distance between punctures being smaller than the puncture diameter. The legs are dull yellow and slender.

Abdomen. The abdomen is dull yellow.

Genitalia. The aedeagus has a spatula-like appearance in dorsal view, with a poorly sclerotized basal region (Fig. 18 P, Q ). It measures 3 - fold longer than its width, appearing almost parallel-sided and narrowed to a rounded apex. It is almost uncurved in lateral view. There are V-shaped phallobase apodeme rings around and keeling the median lobe.

Female. The body of females is larger than that of males, measuring 4.7–5.1 mm in length.

Genitalia. The spermatheca is J-shaped and swollen (Fig. 18 R ). The cornu is gradually narrowed toward the blunt apex. The ductus spermatheca is thin, exceedingly elongated, and regularly and tightly coiled.

Pupa. The body is pale brown, elongated, and flattened dorsoventrally (Fig. 18 S ). Abdominal segments I – IV feature acuminate bifurcated lateral processes at the apical region, with the ventral process smaller than the dorsal process. The processes of segment IV are significantly enlarged, and the ventral process is particularly thick and projecting diagonally backward, with a hooked tip. Segments V – VII feature bifurcated processes, with greater bifurcation of the ventral processes. Segments VIII and IX are fused, exhibiting two blunt processes apically.

Distribution.

Around Obi, Southern Miyazaki Prefecture, Japan.

Host plants.

Rubiaceae : Adina pilulifera (Lam.) .

Leaf mine.

Full-depth, linear-blotch mine on mature leaf, often transitioning into a radiate mine (Fig. 18 T – W ). The larvae create holes that penetrate the upper and lower layers of the leaf, with frass being discharged outside through the holes. Holes form intermittent lines along the sides of the mine. Larvae sometimes exit the mine and move to another leaf to construct a new mine. Fully grown larvae pupate in the pupation chamber located nearly at the center of the mine, typically on the midrib. The upper layer of the leaf around the chamber remains undamaged and green.

Etymology.

The species name refers to the genus name of the host plant, Adina.

Japanese name.

Obi-togehamushi.

Remarks.

Dactylispa exhibits considerable diversity in China ( Chen et al. 1961; Chen and Tan 1964). This newly discovered species resembles Dactylispa nigrodiscalis , a Chinese species, in terms of its habitus, presence of trifurcate anterior spines on the prothorax, arrangement of spines on the elytra ( Gressitt 1938), and association with the host plant family ( Rubiaceae ). However, it is differentiated from the latter by the presence of a pair of anterior trifurcate spines of the prothorax that are widely separated from each other, with the distance between spines being subequal to the width of the occiput but less than three-quarters of the width in the latter. The first and second lateral spines on the prothorax of the newly identified species branch basally, whereas in D. nigrodiscalis , the first and second lateral spines on the prothorax share common stems. Moreover, the former is associated with Adina pilulifera as the host plant species, whereas the latter is associated with Metadina trichotoma , Mussaenda pubescens , and Uncaria rhynchophylla ( Yang et al. 2023) . Given that D. nigrodiscalis belongs to the subgenus Triplispa ( Zhang et al. 2021) , this new species is considered a member of Triplispa .

This newly discovered species resembles Dactylispa issikii Chûjô, 1938 in terms of the presence of trifurcate anterior spines on the prothorax. However, it is distinguished from the latter by the presence of yellow spines on the prothorax compared to black in the latter, the presence of a yellow area on the pronotum and elytron compared to a black pronotum and elytron in the latter, completely yellow sternum compared to a dark brown sternum in the latter, more and shorter lateral spines on the elytron, and association with the host plant family Rubiaceae compared to Poaceae in the latter.

Although the new species is similar to Dactylispa higoniae in terms of habitus, it is distinguished from the latter by the presence of trifurcate anterior spines on the prothorax compared to bifurcate spines in the latter, yellow propleuron and sternum compared to their dark brown color in the latter except along the longitudinal suture, and association with the host plant family Rubiaceae compared to Lamiaceae for the latter.

Figures

Figure 18. Adult morphology, male genitalia, and leaf mines of two Dactylispa species A – H D. higoniae I – W D. adinae sp. nov. A – L dorsal (A, I), ventral (B, J), lateral (C, K), frontal (D, L) views of adults M lateral view of prothorax N dorsal view of prothorax O arrangement of spines on interstices I – VIII of left elytra (yellow circles denote spines on interstices, size of circle indicates length of spine) E, F, P – Q aedeagus in male genitalia (E, P ventral, F, Q lateral) R spermatheca and ductus spermatheca in female genitalia S ventral view of pupal exuvia G, H, T – W leaf mines. Host plants G, H Callicarpa mollis T – W Adina pilulifera at Inohae, Nichinan, Miyazaki Pref. An arrow in W indicates pupation chamber.