Fig. 2
From: Homeosis in a scorpion supports a telopodal origin of pectines and components of the book lungs
Wild type (a, f) and inferred homeotically transformed (b–e, g, h) structures of the mesosoma. (a) The wild type genital operculum is bilobed and anterior of the wing-like pectines. (b) In this specimen, the right genital operculum (go) bears a partial walking leg (gl) with telotarsal macrosetae on the distal edge (see e for labels). The left genital operculum bears a partially developed bud (green structure). Both pectines are transformed into legs (pl), with clear segmentation and a pair of tarsal claws on the left pectine. (c) Two developing spermatophores (se, red arrows) of the homeotic mutant have different sizes. (d) A triangular notch (bn) on basal piece of the homeotic scorpion. (e) Drawing of B showing homeotically transformed structures, red structure is genital papilla; bp, basal piece. (f) Sternite 5 and sternite 6 of a wild type individual showing symmetrical margins and stigmata (st). (g, h) External (g) and internal (h) views of homeotic sternite 5 and sternite 6, showing book lung (bl), everted structure (red arrow) and notches (blue arrows)