Kotov A.A. 2013. On the homology of the frontal head pore in Cladocera (Crustacea: Branchiopoda) // Invertebrate Zoology. Vol.10. No.2: 281–290 [in English].
A.N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071, Russia,. e-mail: alexey-a-kotov@yandex.ru
doi: 10.15298/invertzool.10.2.06
KEY WORDS: Cladocera, Cladoceromorpha, functional morphology, morphological evolution, homology, frontal head pore.
ABSTRACT: A frontal head pore is found in all representatives of the order Anomopoda (Cladocera) except for three genera: Daphnia O.F. Müller, 1785 (Daphniidae), Moinodaphnia Herrick, 1884 and Moina Baird, 1850 (Moinidae). It is also found in a representative of the order Onychopoda in the genus Polyphemus O.F. Müller, 1785. Earlier, this structure was detected in a few representatives of the orders Ctenopoda (Penilia Dana, 1852) and Haplopoda (Leptodora Lilljeborg, 1861). The presence of such a pore is a plesiomorphy of the Cladocera. The frontal head pore in the Cladocera and the Cyclestherida (Cladoceromorpha) is homologous to a pore in “Conchostraca” and Notostraca, which is the opening of a duct connecting the eye chamber with the environment, although its connection with the eye capsule in the Cladocera is not confirmed. The function of this pore is unknown, however a duct running into the head from the former, in the cladocerans and “conchostracans” obviously involves the ocellus and the frontal organ. Though poorly studied, the latter has a sensory function, which could suggest a participation of the frontal head pore in these functions.