Skip to main content

Taiwanese ambrosia beetle (Eccoptopterus formosanus) and midst ambrosia beetle (Eccoptopterus intermedius)

Taiwanese ambrosia beetle (Eccoptopterus formosanus) and midst ambrosia beetle (Eccoptopterus intermedius)

NEWS - Two xyleborine ambrosia beetles, Taiwanese ambrosia beetle (Eccoptopterus formosanus Lin, Sittichaya & Smith, sp. nov.) and midst ambrosia beetle (Eccoptopterus intermedius Sittichaya, Lin & Smith, sp. nov.) described from Taiwan and Thailand based on DNA sequences (COI and CAD) and morphological characteristics.

Eccoptopterus Motschulsky 1863 is the earliest described xyleborine ambrosia beetle (Coleoptera: Curculionidae: Scolytinae). Victor Ivanovich Motschulsky assigned the name to the monotypic genus and a new species, E. sexspinosus Motschulsky 1863, described from Burma.

Currently 14 species and subspecies have been described of which 4 are: E. drescheri Eggers 1940, E. limbus Sampson 1911, E. spinosus (Olivier, 1800) and E. tarsalis Schedl 1936. Eccoptopterus is easily distinguished by its autapomorphically enlarged metatibiae and metatarsi.

Based on specimens collected as part of a survey of xyleborine ambrosia beetles in Thailand and Taiwan, researchers have found variations in Eccoptopterus specimens that suggest the potential for a new species.

E. formosanus female, 2.56−2.64 mm long (mean = 2.61 mm; N = 4), 2.13−2.17× as long as wide (mean = 2.14×; N = 4). Medium body size, declivital armature composed of a pair of major spines on declivital summit and 2–4 minor denticles unevenly spaced on each lateral margin; protibiae slender, broadest at apical 1/3, outer margin armed with six or seven moderated socketed denticles; scutellum broadly linguiform; elytra tapering laterally.

Bred from Elaeocarpus sylvestris (Lour.) Poir. (Elaeocarpaceae), Lithocarpus hancei (Benth.) Rehder, Quercus glauca Thunb. ex Murray (Fagaceae), Sapium discolor Muell.-Arg. (Euphorbiaceae), Trema orientale (L.) Blume (Cannabaceae) with a diameter of about 4.8–6.2 cm in Taiwan. The radial entrance gallery leads to several branches in various planes without enlarged brood chambers.

E. intermedius female, 1.70−1.90 mm long (mean = 1.80 mm; N = 6), 2.03−2.38× as long as wide (mean = 2.13×; N = 6). Small body size, declivital armature composed of a pair of major spines at interstriae 3 on declivital summit and four minor spines unevenly spaced on each lateral margin, declivity covered with flattened scale-like setae; protibiae slender, broadest at apical 1/3, outer margin armed with four or five moderated socketed denticles, elytra tapering laterally.

Formosa is the old name of the island of Taiwan, referring to the location of the type collection with a distribution in Nantou County). L. inter + medius = in the middle. The name refers to the morphological character of the species which is intermediate between E. limbus and E. spinosus. Distribution in Chiang Mai, Lamphun, Tak, Ubon Ratchathani provinces (Thailand).

The differences in COI and CAD sequences between the new species (E. formosanus, E. intermedius) and E. limbus, E. spinosus sensu lato and the junior synonym E. gracilipes are greater than the suggested species boundaries for these genera. Geographically separated morphological characters also show variation in the degree of elytral constriction and density of declivital setals.

E. intermedius is more similar to E. limbus than to E. spinosus but some characters are intermediate. E. intermedius differs from E. limbus by its smaller size, shorter elytra (elytra: pronotum), only four minor spines on the declivital margin, and more slender protibiae. It differs from E. spinosus by its hair-like declivital seta and only one pair of major spines and more slender protibiae.

E. formosanus is more similar to E. spinosus than to E. limbus. E. formosanus differs from E. spinosus in lacking the second and third major spines on the declivital margin and the declivital surface is densely covered with long, thick setae. It differs from E. limbus in having a smaller body size, tapering elytra and a declivital margin with 2–4 minor denticles.

Original research

Sittichaya W, Lin C-S, Smith SM, Pornsuriya C, Cognato AI (2024). Two new species of Eccoptopterus Motschulsky, 1863 ambrosia beetle from Taiwan and Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini). ZooKeys 1217: 247-262, DOI:10.3897/zookeys.1217.129707

Dlium theDlium
Labels:

Popular Posts

Pink jewel dragonfly (Heliocypha fenestrata)

Pink jewel dragonfly ( Heliocypha fenestrata ) is an animal species in Chlorocyphidae, a dragonfly 40-45mm long, slender, predominantly black with bright pink and blue, flies swiftly, large eyes, very long wings, lives near fresh flowing water and waterways. H. fenestrata has a black body with an upper back decorated with three plots of squares in pink and a similar plot on the nape of the top. The sides to the bottom are decorated with plots in light blue. A pair of large, round and black eyes. The tail is long and segmented, cylindrical, predominantly black with several plots of light blue color at the base of the sides, the tip ends with two small tails and curves inward. The legs are jointed and are all black. The wings have a span of up to 80 mm, contain many pulse lines, elliptical tips, are dark and transparent, when exposed to sunlight they give off pink or green or blue or white reflections. Pink jewel dragonfly lives near freshwater ecosystems that flow and low light inten...
Read more

Screw tree (Helicteres isora)

Screw tree ( Helicteres isora ) is a species of plant in the Malvaceae family. It is a shrub or small tree, up to 8 meters tall. It has gray bark and alternate leaves, up to 22 cm long and 17 cm wide, oval in shape, with serrated edges and hairs. The flowers are red or white and reach a total length of 5.5 cm. The fruit is green when unripe, brown or gray when dry, twisted, spiral-shaped, and pointed at the tip. The seeds are black or brown, shiny, and diagonal, triangular, or rectangular. TAXON Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Malvales Family: Malvaceae Subfamily: Helicteroideae Tribe: Helictereae Genus: Helicteres Pluk. ex L. in Sp. Pl.: 963 (1753) Species: Helicteres isora L. in Sp. Pl.: 963 (1753) HETEROTYPIC SYNONYMS Helicteres baruensis var. ovata DC. in Prodr. 1: 476 (1824) Helicteres chrysocalyx Miq. ex Mast. in J.D.Hooker, Fl. Brit. India 1: 365 (1874) Helicteres corylifolia Buch.-Ham. ex Dillwyn in Rev. Hortus Malab....
Read more

Glombang (Lentinus squarrosulus)

Glombang ( Lentinus squarrosulus ) is a species of fungi in Polyporaceae, umbrella-shaped, strong pole, round, chewy and fleshy stamp, white with gray spots forming rings, scaly, growing on wood in tropical regions, fast growth of mycelia used for food and nutraceuticals. L. squarrosulus has a 1.5-10 cm long cap, the surface is convex inward until compressed with a slightly bumpy, jagged margin, initially white to brown at maturity. The bottom surface of the cap has gills, crowded, narrow, white to yellow with rough edges. Stems 20-60x4-10 mm, running to the center, pointing downward, upright or crooked, hairy to scaly, partially creamy veils leaving a ring or light zone towards the top of the stem which may disappear in age or the veil may remain intact and cover the gills. Pileus is thin, tough, fibrous and white. Spores are cylindrical, smooth, nonamiloid, 6-9,52.5x-3.5 μm and white in color. It grows singly but is more common in groups on fallen tree trunks, especially coconut...
Read more