Hylesinus macmahoni ( Stebbing, 1909 )

Buhroo, Abdul Ahad, 2024, A taxonomic monograph of subfamily Scolytinae (Coleoptera: Curculionidae) in the Western Himalaya, Zootaxa 5533 (1), pp. 1-82 : 33-34

24. Hylesinus macmahoni ( Stebbing, 1909)

( Figure 31 )

= Sphaerotrypes macmahoni Stebbing, 1909

= alternans Schedl, 1959a

= fraxinoides Schedl, 1959b ( Leperisinus )

This species is diagnosed by the following morphological characters: ♂ frons broadly impressed above epistomal margin; surface finely reticulate, with close punctures of irregular shape and size and dense stout setae, except on median smooth, impunctate area; vertex convex, finely reticulate and with minute punctures; eyes elongate and entire; antennal scape long, funicle with seven segments, club conical with three distinct sutures; pronotum 1.53× as wide as long, widest at base, lateral sides rounded and gradually incurved from the base, with distinct anterolateral constriction; anterior margin sub rounded; surface rugosely punctate, punctures more prominent, shallow and irregular towards basal half; asperities of different sizes on lateral margins more prominent anteriorly; scale-like setae on pronotal surface, somewhat longer laterally and recumbent towards basal margin; elytra 1.94× as long as pronotum, slightly longer than broad (1.06×); lateral sides sub parallel on basal two-fifth gradually narrowing posteriorly with broadly rounded apex; basal margin each with 12–13 transverse crenulations; striae impressed and narrow with somewhat indistinct punctures; interstriae much wider than striae; interstrial vestiture with three to four rows of scale-like setae, scales blunt at apex; pale scales form a wide band from postero-lateral part of elytra to scutellum, with a further pale area on elytral declivity; rows of tuberculations visible on interstriae more prominent towards elytral base; declivity convex, moderately steep with 2 nd interstriae somewhat depressed; body length: 2.74–2.77 mm, 1.74× as long as wide.

Females are distinct from males in having somewhat flat and feebly impressed frons.

Remarks: Hylesinus macmahoni is very similar to H. tupolevi Stark, 1936 in the elytral coloration, but the setae on the elytra in H. tupolevi are rather sharply pointed whereas, in H. macmahoni the setae are blunt. The species is also very similar to H. cingulatus Blandford, 1894 but differs from it mostly in the elytral setae, which are very short, somewhat rounded and blunt in H. cingulatus .

Material examined: New records: India: 3 ♂ ′s, 1 ♀. Kashmir , Uri, Salamabad (34° 05.186′ N, 074° 01.765′ E, 4415 ft.), A.A. Buhroo, 30.09.2017 ( KUIC). Jammu, Ramban, Govindpora (33° 07.053′ N, 075° 18.967′ E, 5420 ft.), A.A. Buhroo, 10.05.2018 ( KUIC) .

Distribution: India: Jammu and Kashmir. Pakistan

Hosts: Fraxinus excelsior , F. floribunda , Olea europaea ( Oleaceae ).

Phylogenetic assessment:

A phylogenetic analysis of Hylesinus macmahoni , H. varius ( Fabricius, 1775) , H. crenatus ( Fabricius, 1787) , H. fraxini ( Panzer, 1799) and H. wachtli orni Fuchs, 1906 , together with the out-group Hylurgus ligniperda ( Fabricius, 1787) resulted in the formation of clades with bootstrap values more than 90% ( Fig. 32 ). Hylesinus macmahoni was separately monophyletic within the group with well-supported sister clades and its haplotypes were displayed in a single clade with a high bootstrap value. The haplotypes of Hylesinus macmahoni have a nucleotide difference of 2.2%. The interspecific nucleotide divergence ranged 14.71–14.90% between Hylesinus macmahoni and H. varius , 13.4–14% between H. macmahoni and H. fraxini , 12.3–14.6% between H. macmahoni and H. wachtli and 14.7– 16% between H. macmahoni and H. crenatus . The consensus tree, however, demonstrated that H. fraxini and H. varius formed a single cluster with 98% bootstrap value, which also supports the synonymy of H. fraxini under H. varius being morphologically similar species.

Figures

FIGURE 31. Hylesinus macmahoni. Male: dorsal view A, lateral view B, frons C; female: frons D.

FIGURE 32. A phylogenetic tree obtained from the NJ for the COX-1 genes of H. macmahoni (in blue) and related species. Numbers at the branches represent bootstrap values.