First record of gynandromorphy in fossil Chironomidae (Diptera) from Late Eocene Rovno amber

Gynandromorphy as an abnormal mixture of sex-specific traits of males and females in an individual is wide spread among the Chironomidae (Martin and Lee 2000).Gynandromorphy could be caused by mutation in the mitosis regulating genes, which creates an abnormal puzzle of "genetically masculine" and "feminine" body parts, or by other factors like Mermithidae (Nematoda) parasites (Martin 1994).Gynandromorphs can be categorized based on morphology and relationships between "male" and " female" parts of the body.Basically they could be divided in 3 groups: a) anteroposterior gynandromorphs -with anterior and posterior parts of the body possessing traits of different sexes; b) lateral -with body possessing different sexes traits on the left and right sides; c) mosaic -with sexual traits creating a sophisticated puzzle where wings and limbs can be attributed to the phenotypes of different sexes (Martin 1994, Rempel 1940).Studies of gynandromorphs are important for understanding Chironomidae sex determination mechanisms and evolution of the group.Up to now, gynandromorphs have been recorded only in recent Chironomidae.Herein we present the first fossil record of Chironomidae gynandromorphy based on an inclusion in the Late Eocene Rovno amber from Ukraine.Late Eocene Rovno amber represents a southern coeval analogue of Baltic amber (Baranov et al. 2014).Chironomids are diverse and abundant in Rovno amber, with up to 15 genera from 4 subfamiles recorded from that deposit, three of these genera being known only from Rovno amber (Baranov et al. 2014;Giłka et al. 2013, Zelentsov et al. 2012).The gynandromorph was found during a survey of the I.I.Schmalhausen Institute of Zoology collection of nematoceran Diptera in amber.