On the taxonomy of Palaemon javanicus Heller, 1862, and Palaemon sundaicus Heller, 1862, with description of a new species of Macrobrachium Bate, 1868 (Crustacea: Decapoda: Caridea: Palaemonidae) from Southeast Asia

Re-examination of the type material of Palaemon javanicus Heller, 1862, shows that the current concept of the species is wrong. This species is in fact a senior subjective synonym of a widespread Southeast Asian species now known as Macrobrachium trompii (De Man, 1898). The species now commonly referred to as "Macrobrachium javanicum" following De Man (1879) from Southeast Asia is in fact, undescribed, and is here named Macrobrachium duri spec. nov. Macrobrachium duri spec. nov. can easily be distinguished from M. javanicum sensu stricto by the presence of a small triangular median process on the fourth thoracic sternite, possessing spinulate third to fifth pereiopods, having both second periopods covered with spines and few scattered short stiff setae, and the eggs been small and numerous. To add to the confusion, Palaemon javanicus Heller, 1862, is also synonymous with P. sundaicus Heller, 1862, and both were described by Heller (1862) in the same paper, making both names simultaneously available. As first revisors, we hereby choose P. sundaicus Heller, 1862, to have priority over P. javanicus Heller, 1862, when the two names are considered to be synonyms. Palaemon sundaicus Heller, 1862, is therefore also the senior synonym of Macrobrachium trompii (De Man, 1898).