Fornshell J.A. 2014. Larvae of the pycnogonids Ammothea striata (Möbius, 1902) and Ammothea carolinensis Leach, 1814 described from archived specimens // Invertebrate Zoology. Vol.11. No.2: 325–334 [in English].

National Museum of Natural History, Department of Invertebrate Zoology, Smithsonian Institution, 4210 Silver Hill Road, Suitland, Maryland 20746, USA, e-mail:

doi: 10.15298/invertzool.11.2.03

ABSTRACT: The lecithotrophic larva of two species in the family Ammotheidae Dohrn, 1881, Ammothea striata (Möbius, 1902) and Ammothea carolinensis Leach, 1814 are described from archived specimens. Larvae were recovered from the ovigers of adult male specimens. The three post-embryonic instars from second to fourth of A. carolinensis were present on the archived specimens. Two stages of A. striata larvae were present, presumably the second and third post-embryonic instars. Larvae were studied using a scanning electron microscope. The length of larvae and measurements of the cheliphores, larval appendages II and III are reported. The development of the first two walking legs is reported for the second through the fourth instars of A. carolinensis and second and third instars of A. striata. Larval appendages III show varying patterns of reduction during the post-embryonic development of the members of the genus Ammothea. The patterns present in A. striata and A. carolinensis are compared to those found in five other members of the genus Ammothea, A. gigantea Gordon, 1932, A. glacialis (Hodgson, 1907), A. longispina Gordon, 1932, A. bicorniculata Stiboy-Risch, 1992, and A. spinosa (Hodgson, 1907). Two other species from the family Ammotheidae, Tanystylum bealensis and T. orbiculare Wilson, 1878, are also compared.

KEY WORDS: Pycnogonida, larvae, protonymphon, morphology, SEM.

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