Metaphrixus, Nierstrasz & Brender

Ribeiro, Felipe Bezerra, Horch, Amanda Porciuncula, Terossi, Mariana & Mantelatto, Fernando Luis, 2024, A new species of Metaphrixus Nierstrasz & Brender à Brandis, 1931 (Isopoda: Bopyridae: Hemiarthrinae) associated with an Hippolytidae shrimp from Costa Rica, Zootaxa 5501 (3), pp. 458-466 : 463

Key to species of Metaphrixus parasitizing caridean shrimps in the world based on adult females

1a. First two pereopods on convex side....................................................................... 2

1b. First two pereopods fully developed plus a third pereopod reduced on convex side.................................. 4

2a. Antennules and antennae as unsegmented flaps........................ M. carolii Nierstrasz & Brender à Brandis, 1931

2b. Antennule and antennae segmented....................................................................... 3

3a. Antennae of five articles, head indistinctly separated from pereon, attached ventrally on host............................................................................... M. setouchiensis Shimomura, Ohtsuka & Sakakihara, 2006

3b. Antennae of three articles, head distinctly separated from pereon, attached dorsolaterally on host...... M. intutus Bruce, 1966

4a. Antennule of three articles, head quadrangular and distinctly separated from pereon.......... M. rastriferis Markham, 1990

4b. Antennule of two articles, head subquadrangular and distinctly separated from pereon laterally but not medially............................................................................................. M. wehrtmanni sp. nov.