LARVAL DEVELOPMENT OF THE , MICROEURAPHIA WITHERSI (CIRRIPEDIA, , CHTHAMALIDAE) REARED IN THE LABORATORY

BY

HENGXIANG LI1,2), SUYING MIAO3,4),YANYAN1), XIUJUAN YU1) and LVPING ZHANG1) 1) Key Laboratory of Marine Bio-resources Sustainable Utilization (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China 2) Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 3) School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China

ABSTRACT

The larvae of Microeuraphia withersi cultured in our laboratory passed through six naupliar stages and a cypris stage. Morphological characters including the cephalic shield, frontolateral horns, labrum, hind body, antennules, antennae, and mandibles in all naupliar stages are described and il- lustrated based on observation by compound light microscope and scanning electron microscope (SEM). The larvae from different stages can easily be distinguished by their distinct diagnostic fea- tures in each stage. The ultrastructure of the frontolateral horns, cephalic shield, and hind body of the nauplii, also the head shield, lattice organs, and antennules of the cyprid, are shown for the first time with SEM images. In the present study, differences in morphological description were found with those in the previous studies. Comparison of the larval morphological characters in the chthamalid species, Microeuraphia withersi, malayensis, C. challengeri, Pseudoctomeris sulcata, and Chinochthamalus scutelliformis, showed that some morphological characters can be similar in the nauplii and/or cyprids of these species.

RÉSUMÉ

LeslarvesdeMicroeuraphia withersi élevées dans notre laboratoire passent par six stades nau- plius et un stade cypris. Des caractères morphologiques incluant le bouclier céphalothoracique, les cornes fronto-latérales, le labrum, l’arrière du corps, les antennules, antennes et mandibules chez tous les stades nauplius sont décrits et illustrés à partir d’observation par microscopie classique et microscopie électronique à balayage. Les larves des différents stages sont facilement distinguables grâce à des caractères distincts permettant le diagnostic de chaque stade. L’ultrastructure des cornes fronto-latérales, du bouclier céphalique et de l’arrière du corps des nauplii, mais aussi du bouclier

4) Corresponding author; e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2011 Crustaceana 84 (2): 129-152 Also available online: www.brill.nl/cr DOI:10.1163/001121610X551863 130 HENGXIANG LI ET AL. céphalique, organe dorsal et antennules des cypris, sont montrés pour la première fois avec des im- ages par balayage. Dans cette étude, des différences morphologiques par rapports aux descriptions antérieures ont été trouvées. La comparaison des caractères morphologiques larvaires des espèces de chthamalidés Microeuraphia withersi, Chthamalus malayensis, C. challengeri, Pseudoctomeris sul- cata,etChinochthamalus scutelliformis, montrent que certains caractères morphologiques peuvent être semblables chez les nauplii et/ou les cypris de ces espèces.

INTRODUCTION

Microeuraphia withersi (Pilsbry, 1916) is an Indo-West Pacific species, rang- ing from China, the Palau lslands, the Philippines, Malaysia, and the Mergui Archipelago, to Madagascar and Australia (Jones et al., 2000; Liu & Ren, 2007). This species lives gregariously on rocks, water-front structures, mangrove leaves, and wood in the high intertidal, and sometimes can become a predominant species in biofouling (Liu & Ren, 2007). Microeuraphia withersi was first described as Chthamalus withersi in previous literature (Pilsbry, 1916; Nilsson-Cantell, 1938; Zevina & Tarasov, 1963; Pope, 1965; Daniel, 1974), later transferred to the genus Euraphia Newman & Ross, 1976 (cf. Newman & Ross, 1976; Karande, 1999), and is now referred to the new genus Microeuraphia Poltarukha, 1997, which was sep- arated from the previous genus Euraphia (cf. Poltarukha, 1997). The larval devel- opment of M. withersi has been briefly described from the Indian Ocean (Karande, 1999). However, this description is not complete, as many morphological details still remained unknown, such as the setal formulae of the appendages, the struc- ture of the frontolateral horns and cephalic shield in the nauplii, as well as the morphology of the cyprids. In this paper, observations of the larval morphology of M. withersi were made using the compound light microscope and the scanning electron microscope, in an attempt to discover more diagnostic characters of this species. Detailed morphological descriptions of the nauplii and cypris larvae reared in the laboratory are thus presented. Differences in morphological characters of the larvae from different stages of the species from China and India are compared. The larvae of Microeuraphia withersi are also compared with those of other chthamalid species, in order to elucidate the larval taxology and phylogenetic evolution of the Chthamalidae.

MATERIAL AND METHODS

Adult Microeuraphia withersi were collected from high intertidal rocks at the Bailong peninsula, Fangchen Harbour City, China, in May 2008. Egg masses