A REDESCRIPTION OF ACANTHONYX PETIVERII H. MILNE EDWARDS, 1834, AND DESIGNATION OF A NEOTYPE FOR ACANTHONYX SIMPLEX DANA, 1852 (BRACHYURA, MAJIDAE)

BY

ESTEBAN J. M. EMPARANZA1,3), GUILLERMO L. GUZMÁN1) and PETER K. L. NG2) 1) Museo del Mar, Departamento de Ciencias del Mar, Universidad Arturo Prat, Casilla 121, Iquique, Chile 2) Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 119260, Republic of Singapore

ABSTRACT The identity of the problematic spider crab species, Acanthonyx simplex Dana, 1852, originally described from Hawaii and never reported since, is resolved. It is here shown to be identical to Acanthonyx petiverii H. Milne Edwards, 1834, a species that is widely distributed on both sides of the American continent. The supposed type locality of Acanthonyx simplex is almost certainly wrong. Acanthonyx petiverii, nevertheless, is a highly variable species and, as such, is redescribed in detail. To ensure a stable taxonomy for these species and the genus, a neotype for A. simplex is designated.

RESUMEN La problemática identidad de la especie de cangrejo araña Acanthonyx simplex Dana, 1852, originalmente descrita para las costas de Hawai y nunca estudiada desde entonces, ha sido determinada. Aquí se demuestra que es idéntica a Acanthonyx petiverii Milne Edwards, 1834, especie que se distribuye en ambas costas del continente Americano. La supuesta localidad tipo de Acanthonyx simplex es, casi con certeza, un dato erróneo. Acanthonyx petiverii, no obstante, es una especie altamente variable morfológicamente y, en consecuencia, se redescribe en detalle. Para estabilizar la taxonomía, se designa un neotipo para la especie A. simplex.

INTRODUCTION The majid genus Acanthonyx Latreille, 1828 currently contains 17 species (table I), most of which occur in the Atlantic and Indian Ocean. In the Pacific

3) Current address: Billund Aquaculture Chile S.A., Bernardino 1057, Módulo 13, Parque Industrial San Andrés, Puerto Montt, Chile; e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2007 Crustaceana 80 (5): 533-543 Also available online: www.brill.nl/cr 534 E. J. M. EMPARANZA, G. L. GUZMÁN & P. K. L. NG

TABLE I List of the known species of Acanthonyx

Current name Original genus Subjective synonyms assigned Acanthonyx consobrinus Acanthonyx — A. Milne-Edwards, 1862 Acanthonyx dentatus Acanthonyx Dehaanius acanthopus MacLeay, 1838 H. Milne Edwards, 1834 Acanthonyx depressifrons Acanthonyx — Manning & Holthuis, 1981 Acanthonyx dissimulatus Coelho, 1993 Acanthonyx — Acanthonyx elongatus Miers, 187? Acanthonyx — Acanthonyx euryseroche Acanthonyx — Griffin & Tranter, 1986 Acanthonyx formosa Acanthonyx — Wu, Yu & Ng, 1999 Acanthonyx inglei Acanthonyx — Tirmizi & Kazmi, 1988 Acanthonyx limbatus Acanthonyx — A. Milne-Edwards, 1862 Acanthonyx lunulatus (Risso, 1816) Maia Maia glabra Latreille, 1836 Acanthonyx viridis Costa, 1838 Gonosoma viridis Costa, 1844 Acanthonyx brevifrons A. Milne- Edwards, 1869 Acanthonyx minor Acanthonyx — Manning & Holthuis, 1981 Acanthonyx nodulosa (Dana, 1852) Peltinia — Acanthonyx petiverii Acanthonyx simplex Dana, 1852 H. Milne Edwards, 1834 (present study) Peltinia scutiformis Dana, 1851 Acanthonyx emarginatus H. Milne Edwards & Lucas, 1843 Acanthonyx debilis Dana, 1851 Acanthonyx concamerata Kinahan, 1857 Acanthonyx quadridentatus Acanthonyx — Krauss, 1843 Acanthonyx sanctaehelenae Acanthonyx — Chace, 1966 Acanthonyx scutellatus MacLeay, 1838 Acanthonyx Acanthonyx macleaii Krauss, 1843 Acanthonyx undulatus Barnard, 1947 Acanthonyx —

Ocean, there are only three known species, viz., A. petiverii H. Milne Edwards, 1834, A. simplex Dana, 1852, and A. formosa Wu, Yu & Ng, 1999 (cf. Dana, 1852; Manning & Holthuis, 1981; Griffin & Tranter, 1986; Wu et al., 1999). Acanthonyx simplex was described from one specimen, supposedly originating