Mysidacea: Families, Subfamilies and Tribes

Kenneth Meland

Rhopalophthalminae Hansen, 1910

Diagnostic description. Head. Carapace short, last 2 or 3 thoracic somites exposed dorsally. Rostrum obtuse. Eyes normally developed. Antenna (antenna 2) scale with apical suture, outer margin smooth, without setae, with terminal spine. Labrum symmetric. Mandible lacinia mobilis well developed, on left mandible spine row absent to spine row reduced to a single spine (supporting a single thick seta on right mandible), molar process well developed.

Thorax. 1st maxilliped exopod well developed. 2nd thoracopod developed as a maxilliped, exopod well developed. 3rd-8th thoracopods endopod with fused carpus and propodus (tarsus), carpopropodus divided into a few subsegments (8th endopods reduced to unsegmented vestiges). Branchiae on thoracopods absent. Marsupium composed of three pairs of oostegites.

Abdomen Abdomen pleural plates absent, or male pleural plate 1 weakly developed. 6th & 7th abdominal somites fused. 1st pair endopod reduced; 2nd pair exopod elongated; 3rd pair biramous; 4th pair biramous; 5th pair biramous. Female pleopods uniramous or greatly reduced. Uropod endopod with distal articulation; setose around entire margin, statocyst present; exopod with distal articulation, setose around entire margin. Telson apex entire.

Generic composition. Rhopalophthalminae contains 1 genus (17 species): Rhopalophthalmus Illig, 1906 (17 species).

Remarks. The majority of Rhopalophthalminae are found in brackish and littoral waters around Australia, with coastal species extending through the Indian Ocean and up along the western Pacific into Sagami Bay, Japan. A few species are also reported from the southern Atlantic and Mediterranean Sea.

The Rhopalophthalminae are easily recognized by both exo- and endopods of the uropod being divided by a sharp suture, not seen in other Mysidacea.

Cite this publication as: 'Meland, K. (2002 onwards). Mysidacea: Families, Subfamilies and Tribes. Version 1: 2 October 2002.'.