Stethorus keralicus Kapur, 1961

Stethorus keralicus Kapur

( Figs 9a–l View FIGURE 9 , 10a–h View FIGURE 10 )

Stethorus keralicus Kapur, 1961: 35 .

Stethorus curvus Hoàng, 1985: 28 . Synonymized by Poorani 2017: 596.

Diagnosis. Length: 0.85–0.90 mm; width: 0.70–0.80 mm. Form elongate oval and narrowed at both ends; dorsum convex; head and pronotum sparsely but uniformly pubescent; elytra with a mixture of long setae mainly confined to the anterior half and lateral margins, and very short, erect setae on disc and in the posterior half ( Figs 9a View FIGURE 9 , 10h View FIGURE 10 ). Dorsum black; ventral side black except mouthparts and antenna yellowish-testaceous, legs brownish testaceous except all coxae black, tibiae and tarsi yellowish-testaceous. Antenna 10-segmented ( Fig. 9b View FIGURE 9 ). Prosternal process broad and quadrate ( Fig. 9c, d View FIGURE 9 ). Elytral punctures large, thimble-like, and widely separated. Abdominal ventrites with yellowish pubescence, noticeably longer on ventrites 5 and 6. Abdominal postcoxal lines ( Fig. 9e–g View FIGURE 9 ) complete, shallowly semicircular, reaching up to middle of ventrite 1, with punctures confined to the anterior half of the enclosed area. Male genitalia ( Fig. 9h–j View FIGURE 9 ) with penis guide strongly curved ( Fig. 9h View FIGURE 9 ), penis as illustrated ( Fig. 9i, j View FIGURE 9 ). Female genitalia with spermatheca large and globular with a short neck ( Fig. 9k, l View FIGURE 9 ).

Life stages. Life stages as illustrated in Fig. 10a–h View FIGURE 10 .

Material examined. INDIA: Tamil Nadu: Podavur, NRCB Research Farm , N10°47'20.16" E078°34'29.88", 20.xi.19, 13.vi.25, 16.ix.25, feeding on Raoiella indica on banana, R. Thanigairaj, 25 ex. (ICAR-NRCB) GoogleMaps .

Distribution. India ( Gujarat, Karnataka, Kerala, Tamil Nadu); Vietnam.

Biology. Collected in association with Raoiella indica on arecanut, banana, coconut, date palm, and jamun (personal observations, label data).

Barcode sequence. A barcode sequence of the material collected on banana is deposited in GenBank (accession number OR739411.1).

Notes. This is the smallest Indian species of Stethorus that can be readily identified by characteristic elytral pubescence and punctation, 10-segmented antenna, and the much broader prosternal process, and the genitalia of both sexes are also diagnostic. Kapur (1961) mentioned that the male genitalia in S. keralicus lacks a sipho (‘penis’), but it is present and extremely hard to take out of the strongly curved penis guide. The spermatheca is large, globular or pot-shaped, with a narrow neck, and is diagnostic. Due to these unusual characters, it is an outlier in Stethorus as it does not truly belong in either of the two subgenera and the larvae also appear to be distinctive. Vidya et al. (2022) also recovered S. keralicus in a distinct clade separate from other Stethorus spp. in their phylogenetic analysis of Stethorini of southern India and stated it was genetically the most distant species. It is a specific predator of R. indica on banana and various palms, particularly coconut.