Indomias cretaceus (Faust)

Y, R A M A M U Rt H & Ayri, Shaloo, 2010, Revision of the genus Indomias Marshall (Coleoptera, Curculionidae, Entiminae, Tanymecini) from India, Zootaxa 2357, pp. 1-49 : 29-30

6. Indomias cretaceus (Faust)

(figs. 2, 28, 53, 86, 137, 154, 165, 189, 190 and 191)

Sympiezomias cretaceus Faust, 1897: 340 ; Marshall, 1916: 167; 1941: 350 [SMTD]

Description: Colour uniformly black, chalky white or pale green vestiture, without pollinose lateral stripe on elytra. Head convex, as long as rostrum, with scattered deep punctations; frons as broad as rostrum at anterior margin. Rostrum transverse, plain dorsally, 1.1x as broad as long, anterior margin 0.87x as broad as posterior margin; median furrow uniformly broad throughout, distinct up to anterior margin; lateral carinae distinct; scrobes broadest at middle, narrowed and pointed anteriorly, rounded posteriorly, space between scrobes as much as space between eyes. Eyes oval and dorsolateral (figs. 2 and 28). Antennae reddish brown; scape gradually broadened; funicle with first segment 1.1x as long as second, third and fourth equal bead like, fifth and sixth equal; club conical, entire surface densely hairy (fig. 53). Prothorax 1.1x as broad as long, its breadth at middle 1.1x as that of posterior margin; sides rounded throughout and strongly narrowed anteriorly; anterior margin 0.87x as that of posterior margin, truncate dorsally and oblique laterally, posterior margin subtruncate; upper surface with coarse, confluent punctations and interspaces granulate. Legs with hind tibial apex without any dense golden yellow hairs. Elytra ovate, basal margin strongly raised with acute external angle, humeral fold prominent, not impressed on declivity, with acute external basal angle; apices rounded in male, separately pointed but not truly mucronate in female; stria deeply punctatostriate; intervals slightly convex, with short, elongate scales; dorsal outline much convex, deepest near the middle and gradually sloping behind; ratio of length between basal margin to posterior declivity and from posterior declivity to apex 0.9:1; elytral vestiture with predominant reddish scales, ovate with 7–8 ridges (fig. 86). Venter with elongate scales on the first two ventrites, short and flattened, as compared to I. decipiens .

Male genitalia: Aedeagus with median lobe, short, broad, broadest at junction with apophyses, apex pointed, length: breadth ratio 5.8:1, apophyses short, only 0.5x as long as median lobe, apices broadly rounded (figs. 189–190). Tegmen with dorsal piece 3x as broad as the basal piece; parameres very short, with pointed apices; manubrium moderately long, 0.57x as long as the median lobe, it is bent throughout its length, apex bluntly rounded (fig. 191). Spiculum gastrale with shaft as long as median lobe, slender at middle, broad at either ends, apex bent acutely and rectangular; basal prongs subequal with rounded apices (fig. 165).

Female genitalia: Spermatheca with proximal arm swollen, 3x as broad and 0.64x as long as the distal arm, angle between the arms obtuse; nodulus globular, ramus cuboidal, 3.4x as broad as nodulus; cornu narrowing towards smoothly rounded apex (fig. 137). Spiculum ventrale with shaft moderately long, uniformly thick, its apex bluntly rounded; basal plate 0.33x as long as shaft spatulate, longer than broad (1:0.7), with basal half rectangular, apical half subconical, apex blunt with tuft of hairs (fig. 154).

Length: male, 6–6.5 mm; female, 8.5–9.5 mm. Breadth: male, 2.5–3.0 mm; female, 3.25–3.60 mm.

Specimens examined: 2 male, INDIA: Tamil Nadu: Gudalur: Nilgirii Hills: 3500 ft, 1949, without collector's name; 1 female, Karnataka: Bangalore: 26.VIII.1913, Coll. T.B. F., on mulberry; Nilgirii Hills, without date and collector's name; 1 male, Coimbatore; Bailur forest, 23–28.XI.1913, Coll. Ramakrishna; Nilgirii Hills: Adderley: 3000 ft, 26.IV.1915, Coll. G.R. Dutt; Karnataka: Bangalore, 24.VI.1908, Coll. T.V.R.; Karnataka: Bangalore: VI.1906, Coll. T.V.R.; Kerala: Malabar: Dhony forests: 26.V.1922, Coll. Ramakrishna; 6 specimens, Karnataka: Bangalore: PDBC, 3.VII.1998, Coll. J. Poorani, on redgram; 6 specimens, Karnataka: Bangalore: PDBC, 25.V.1998, Coll. J. Poorani, on rose; Tamil Nadu: Thadiyankudisai, 24.VII.1999, Coll. S. Suresh, on coffee; 3 specimens, Karnataka: Bangalore: PDBC, 25.V.1998, Coll. J. Poorani, on radish.

Distribution: India: Karnataka: Tamil Nadu

Associated habitats: Coffee, radish, rose, redgram, and mulberry.

Taxonomic note: This species exhibits sexual dimorphism in size; females are more robust than males. Marshall (1916) stated that apical margin of prothorax is vertically truncate laterally, but it has been found that it is obliquely truncate.

Economic importance: It is reported to be a vector of sandal spike disease in sandal ( Hart and Rengaswamy, 1926; Anonymous, 1932, 1933). It was reported feeding on coffee ( Ayyar, 1922), mulberry ( Wadhi and Batra, 1964) and on Rawolfia seperpentina plantations (Pratap Singh, 1964).

(ii) Slightly broader Female I. beesoni (iii) Broader Female I. prasinus

b. Development of humeral fold (i) Practically absent Male I. praeteritus (ii) Developed but does not project beyond lateral outline of Female I. praeteritus elytra

(iii) Humeral fold forming a distinctly projecting angle Female I. prasinus (iv) Humeral fold distinct but does not form a projecting Male I. prasinus angle

c. Apex of elytra (i) Rounded Male I. cretaceus (ii) Separately pointed but not truly mucronate Female I. cretaceus (iii) Almost rounded Male I. frater (iv) Slightly mucronate Female I. frater

(v) With short, distinct apical mucros Female I. anamalainus (vi) With short, distinct apical mucros Female I. decipiens (vii) Not mucronate or rounded Male I. lividus

(viii) Scarcely mucronate Female I. lividus