Acetes, H. MILNE EDWARDS, 1830

Vereshchaka, Alexander L., Lunina, Anastasia A. & Olesen, Jørgen, 2016, Phylogeny and classification of the shrimp genera Acetes, Peisos, and Sicyonella (Sergestidae: Crustacea: Decapoda), Zoological Journal of the Linnean Society 177 (2), pp. 353-377 : 358-360

ACETES H. MILNE EDWARDS, 1830

Diagnosis: Carapace and abdomen smooth, firm; labrum not much separated from antennae and eyes; rostrum acute, with oblique frontal margin; supraorbital and hepatic teeth present; sixth abdominal somite and telson in males without ventral processes; telson without lateral spines; eyestalks not elongated, cornea well pigmented; third antennular segment without ventral processes, longer than first segment; stylocerite present, mobile; mandible with palp; maxillula in adults with a single endite; first maxilliped with endopod and epipod; second maxilliped with epipod; third maxilliped <two times as long as first pereopod, not dimorphic sexually, dactyl subdivided; first pereopod with ischium lacking strong movable spines and reduced chela, fingers subequal; second pereopod with merus lacking proximal protrusion and much reduced chela lacking elongated setae, fingers subequal; third pereopod with much reduced chela lacking strong curved spines and elongated setae, fingers subequal; fourth pereopod in female absent or five-segmented, in male absent or threesegmented; fifth pereopod absent or three-segmented in female, absent or one-segmented (only coxa present) in male; uropodal exopod setose for distal outer margin, with small tooth by far not reaching distal end of exopod. Male clasping organ: well developed, with two devel- oped or rudimentary clasping tubercles, no sensory bristles adjacent to clasping tubercle. Petasma: pars astringens absent or present, pars media if present armed with strong claws; pars externa developed. Photophores: dermal organs and organ of Pesta absent. Branchiae: podobranch on somite VIII, anterior arthrobranchs on somites VIII–XIII, posterior arthrobranchs absent.

Type species: By original designation, Acetes indicus H. Milne Edwards, 1830 .

Species: Acetes americanus Ortmann, 1893 , Acetes binghami Burkenroad, 1934 , Acetes chinensis Hansen, 1919 , Acetes erythraeus Nobili, 1905 , Acetes indicus H. Milne Edwards, 1830 , Acetes intermedius Omori, 1975 , Acetes japonicus Kishinouye, 1905 , Acetes johni Nataraj, 1949 , Acetes marinus Omori, 1975 , Acetes natalensis Barnard, 1955 , Acetes paraguayensis Hansen, 1919 , Acetes petrunkevitchi ( Burkenroad, 1945) , Acetes serrulatus ( Krøyer, 1859) , Acetes sibogae Hansen, 1919 , Acetes vulgaris Hansen, 1919 .

Remarks: The genus Acetes was established by H. Milne Edwards (1830) who described a new species, A. indicus , from the Ganges estuary. A comprehensive study by Omori (1975) of all valid species of Acetes included diagnoses and figures of all known species of the genus. This paper disentangled most of the taxonomic questions within the genus and even made it possible to identify all females, which is unique for Sergestoidea as usually only the adult males can be identified with certainty. Our SEM data on the ultrastructure of the petasma have provided hitherto-unknown morphological details and formed a basis for establishing homologies to other taxa, which is a necessity for phylogenetic studies. In the earliest available identification keys to species of Acetes , males and females were treated separately (e.g. Hansen, 1919), a tradition continued by Omori (1975). Below we provide a combined key for both males and females with citations for the illustrations necessary for reliable identification.