Ictinogomphus decoratus ( Selys, 1854 )

Babu, R., Srinivasan, G. & Subramanian, K. A., 2018, Range extension of Ictinogomphus decoratus (Selys, 1854) (Insecta: Odonata: Gomphidae) to India, Records of the Zoological Survey of India 118 (4) : -

Ictinogomphus decoratus ( Selys, 1854)

1854. Ictinus decoratus Selys, Bull. Acad. Belg. , 21 (2): 89

1936. Ictinogomphus decoratus Lieftinck, De Trop. Natuur , 25: 103.

1939. Indictonogomphus decoratus Fraser, Proc. R. Ent. Soc. London , 8: 21.

Global distribution: Brunei Darussalam, Cambodia, China (Guangxi, Yunnan), Indonesia (Bali, Jawa, Kalimantan, Sumatera), Lao People’s Democratic Republic, Malaysia (Peninsular Malaysia, Sabah, Sarawak), Philippines, Singapore, Thailand, Vietnam ( Manh, 2011).

IUCN Redlist Status: Least Concern (LC) ( Manh, 2011).

Material examined: 1♂, V. K. Pur Nallah (Lat. 10.73260°, Long. 092.56889°), Little Andaman , Andaman and Nicobar Islands, 09.iii.2016, Coll. G. Srinivasan. Field photograph of adult male was taken from same locality. The global distribution map (Map-1) was prepared from data provided by Manh (2011) .

Diagnostic characters: Abdomen 48mm, Forewing 41mm, Hindwing 40mm, Nodal index: FW 13-23/26-13, HW 14- 18/17-14.

The Ictinogomphus decoratus is large dragonfly with a wingspan of 13 to 14 cm. This species is heavily built with very distinctive strong greenish yellow bands and spots on its thorax and abdomen. The eyes are widely separated and grayish green in colour. Prothorax black, thorax broadly black marked with greenish yellow bands and spots. Wings transparent, extreme base tinted with brown, pterostigma black and covering 6-7 cells, Primary antenodals 1 st & 7 th in left fore and hind wing, 1 st and 8 th in right forewing, 1 st and 6 th in right hind wing. Abdomen black marked with greenish yellow, base of S3 to S7 marked with yellow, dorsal carina of S8 and S9 black with basal yellow spot on each side. Epiproct black, very long and terminate in a sharp point, paraproct very short.

Ictinogomphus decoratus can be distinguished from widespread I. rapax (Rambur, 1842) , by a black stripe traversing the lower part of the frons and not expanding upwards at its middle, a humeral stripe represented only by an upper greenish yellow spot, thorax with very broad black stripes on the lateral side and the absence of yellow stripe on the median lateral black band. Dorsal carina of S-8 is completely black and with only basal lateral yellow spot on each side. In I. rapax , the black stripe traversing the lower part of the frons and expand upwards at its middle to divide the yellow area into two large triangular spots. In thorax, the humeral stripe is represented by an upper greenish yellow triangular spot and a lower yellow broad streak. A vestige of a third yellow stripe on the median lateral black band is also present but never complete band. The yellow band on S8 is more than half remain unexplored largely due to their remoteness and inaccessibility. These recent new discoveries emphasize the importance to detailed explorations to unexplored islands for complete documentation of biodiversity of these tropical islands.