Xylosandrus declivigranulatus, (Schedl, 1936)

Smith, Sarah M., Urvois, Teddy, Roques, Alain & Cognato, Anthony I., 2022, Figs. 22 - 27 in Taxonomic and Distributional Notes on the Genus Scymnus Kugelann, 1794 (Coleoptera: Coccinellidae) in Mexico, The Coleopterists Bulletin 76 (3), pp. 367-374 : 371-373

XYLOSANDRUS DECLIVIGRANULATUS ( Schedl, 1936) , status restored Figs. 2–5

Xyleborus declivigranulatus Schedl 1936: 30 . Xylosandrus declivigranulatus ( Schedl, 1936) :

Wood 1977 (as a synonym of X. crassiusculus ).

Diagnosis. This species can be distinguished from other Xylosandrus species by the following combination of characters: 2.1 mm long (n = 3); 2.0× as long as wide; elytral disc gradually curving toward declivity, elytra rounded; posterolateral margins of elytra carinate to interstriae 7; declivital face with six striae; interstriae and striae granulate, interstrial granules strongly confused, strial granules subseriate, declivity appearing dull, with erect hairlike setae longer than the width of two interstriae; pronotum as long as wide, pronotum in dorsal view rounded (type 1) and lateral view basic (type 0), summit at midpoint, basal 1/2 smooth, shiny, sparsely, minutely punctate; and dense mycangial tuft on the pronotal base.

The species can be distinguished from X. crassiusculus by the following combination of characters ( X. declivigranulatus given first): 2.1 mm long vs. 2.3–2.9 mm long ( Smith et al. 2020); 2.0× as long as wide vs. 2.17–2.42× as long as wide ( Smith et al. 2020); pronotum as long as wide vs. 0.73–0.93 times as long as wide; declivity densely granulate, granules spaced by less than one diameter of a granule, surface of declivital face difficult to discern between granules, granules comparatively larger vs. declivity sparsely to moderately granulate, granules spaced 2–5 diameters of a granule, surface of declivital face apparent, granules comparative smaller, often minute.

Type Specimens Examined. Lectotype. [ Malaysia]: Malay Peninsula, Selangor, Kepong , 16.V.1933, A. B. Walton, ex Dipterocarpus baudi (NHMW) ;

2) Dorsal habitus; 3) Lateral habitus; 4) Elytral declivity; 5) Head anterior.

paralectotype as lectotype, except: F . M . S. 1934, F. G . Browne [Bukit lagong Forest Reserve, 6. VI.1934, F. G. Browne] ( FRI) ; paralectotype as lectotype, except: 16. V .1933, A . B . Walton ( NHMUK) .

Non-Type Specimens Examined. Malaysia: Selangor, F. E. S . Serdang , 19.II.1954, I. J . Wyatt (2, NHMUK) ; Selangor, Bukit Lagong For. Res. Kepong , 9. VI .1934, F. G . Browne , ex in wood of felled Sandoricum sp. (2, NHMUK) ; Selangor, Univ. Pertanian , C. I. E. A15664 (1, NHMUK) ; Kelatan, Pulai Chondong , 11. I .1947, F. G . Browne ex. Shorea sp. (1, NHMUK); [Sabah], British North Borneo, 1919, F . Baker (1, NHMUK) . Thailand: Phatthalung Province, Srinagarindra District , Khao Banthat Wildlife Sanctuary, vi.2105, S . Steininger (3, DNA voucher labeled SAX40, MSUC) .

Distribution. West Malaysia (Selangor), East Malaysia (Sabah), and Thailand (Phatthalung) (new record).

Hosts. Dipterocarpus baudi Korth. ( Dipterocarpaceae ) and Sandoricum Rumph. ex Cav. species ( Meliaceae ) ( Schedl 1936).

Remarks. The X. declivigranulatus lectotype and images of a paralectotype were compared to images of the lectotype and two paralectotypes (ZMMU) of Phloeotrogus crassiusculus Motschulsky, 1866 by SMS and AIC and were found not to be conspecific.

Schedl (1936) described X. declivigranulatus for three specimens from Selangor, Malaysia and distinguished it from the closely allied Sumatran species Xyleborus semigranosus Blandford, 1896 (now a synonym of X. crassiusculus ) by the smaller size, stouter form, and more abruptly convex declivity. Schedl (1959) produced a checklist of the Scolytidae of Ceylon and placed X. semigranosus , X. declivigranulatus , and the African species Xyleborus okoumeensis Schedl, 1935 in synonymy with the Japanese species Xyleborus semiopacus Eichhoff, 1878 without comment. Later, Wood (1969) placed X. semiopacus in synonymy with X. crassiusculus . Despite the designation of X. declivigranulatus as a synonym, Browne (1961) continued to recognize the species as a smaller variety of X. semiopacus in Malaysia and noted that it could be distinguished by its smaller body length of 1.9–2.2 mm; our specimens were 2.1 mm. We did not observe any differences in the slope of the elytral declivity.

Figures

Figs. 2–5. Xylosandrus declivigranulatus female, 2.1 mm, collected from Phatthalung Province, Thailand (MSUC).