Embryonic Development of Ampheres leucopheus and Iporangaia pustulosa (Arachnida: Opiliones: Gonyleptidae) PEDRO GNASPINI Ã AND CRISTIANO FREDERICO LERCHE Universidade de Sa ˜o Paulo, Instituto de Biocie ˆncias, Departamento de Zoologia, Rua do Mata ˜o, Sa ˜o Paulo, SP, Brazil The first studies concerning the embryonic development of harvestmen started in the late 19th century, and focused mostly on holarctic species, and only three species of the suborder Laniatores (the largest, among the four suborders considered presently) were studied. Moreover, the last studies on embryology of harvestmen were made during the late 1970s. This study focused on the embryonic development of Ampheres leucopheus (Gonyleptidae, Caelopyginae) and Iporangaia pustulosa (Gonyleptidae, Progonyleptoidellinae). The embryonic development was followed in the field, by taking daily photographs of different eggs during about 2 months. When laid, eggs of A. leucopheus and I. pustulosa have approximately 1.13 and 1.30 mm in diameter, respectively, and the second is embedded in a large amount of mucus. The eggs grow, mainly due to water absorption at the beginning of the process, and they reach a diameter of about 1.35 and 1.59 mm, respectively, close to hatching. It took, respectively, 29–56 days and 35–66 days from egg laying to hatching. For the description of the embryonic development, we use photographs from the field, SEM micrographs, and histological analysis. This allowed us, for instance, to document the progression of structures and pigmentation directly from live embryos in the field, and to record microstructures, such as the presence of perforations in the cuticle of the embryo in the place where eyes are developing. Yet, contrary to what was expected in the literature, we record an egg tooth in one of the studied laniatoreans. J. Exp. Zool. (Mol. Dev. Evol.) 314B:489–502, 2010. & 2010 Wiley-Liss, Inc. How to cite this article: Gnaspini P, Lerche CF. 2010. Embryonic development of Ampheres leucopheus and Iporangaia pustulosa (Arachnida: Opiliones: Gonyleptidae). J. Exp. Zool. (Mol. Dev. Evol.) 314B:489–502. Harvestmen are arachnids characterized by having the prosoma partially fused to the opisthosoma, a pair of exocrine glands opening at the sides of the body, and the presence of a penis and an ovipositor, respectively, in males and females, for direct sperm transfer and egg laying. Currently, four suborders are recognized: Cyphophthalmi, Eupnoi, Dyspnoi, and Laniatores, being the latter the largest (about 3800 species) and represented mostly by tropical species (e.g., Machado et al., 2007; Shultz and Pinto-da-Rocha, 2007; Giribet and Kury, 2007). Studies concerning the embryonic development of harvest- men started in the late 19th century (see Gnaspini, 2007 for a review) and reached its maximum mainly between the 1950s and middle 1970s (Holm, ’47; Pabst, ’53; Immel, ’54, ’55; Moritz, ’57, ’59; Winkler, ’57; Juberthie, ’64; Mun ˜oz-Cuevas, ’71, ’73; Avram, Published online 26 April 2010 in Wiley Online Library (wileyonline library.com). DOI: 10.1002/jezmde.21355 Received 5 August 2009; Revised 18 February 2010; Accepted 30 March 2010 Grant Sponsor: Conselho Nacional de Desenvolvimento Cientı ´fico e Tecnolo ´gico, Brazil (CNPq); Grant number: 142253/2005-7|300326/94- 7|301839/04-2; Grant Sponsor: Fundac - a ˜o de Amparo a ` Pesquisa do Estado de Sa ˜o Paulo, Brazil (FAPESP); Grant number: 00/04686-4. Additional Supporting Information may be found in the online version of this article. Ã Correspondence to: Pedro Gnaspini, Universidade de Sa ˜o Paulo, Instituto de Biocie ˆncias, Departamento de Zoologia, Rua do Mata ˜o, travessa 14, n1 321, 05508-090, Sa ˜o Paulo, SP, Brazil. E-mail: gnaspini@ib.usp.br ABSTRACT J. Exp. Zool. (Mol. Dev. Evol.) 314B:489–502, 2010 & 2010 WILEY-LISS, INC. RESEARCH ARTICLE