bopyrids, Rafinesque, 1815

Romero-Rodriguez, Jesús & Álvarez, Fernando, 2023, Parasitic bopyrid isopods of hermit crabs (Anomura, Paguridae) from the Atlantic coast of Mexico, with notes on their reproduction and distribution, European Journal of Taxonomy 861, pp. 132-167 : 156

Key to genera and species of bopyrids of hermit crabs from the Atlantic coast of Mexico

Based on females, modified from Boyko & Williams 2003 and Williams et al. 2019. Species nonexamined here indicated by *.

1. Attached to the abdomen of the host ( Athelginae ) ............................................................................ 2

– Attached to the branchial chamber of the host ( Pseudioninae ) ......................................................... 5

2. Pleomeres with lateral plates ............................................................................................................. 3

– Pleomeres without lateral plates .......................................................................................................... ............................................ Parathelges ( P. occidentalis * Markham, 1972 only species in the area)

3. Lateral plates on pleomeres 1–5 ........................................................................................................ 4

– Lateral plates on pleomeres 1–3 only .................................................................................................. ...................................................... Stegias ( S. clibanarii Richardson, 1904 only species in the area)

4. Lateral plates on pleomere 5 reduced, globular o scar-like ................................................................. .................................... Pseudostegias ( P. atlantica Lemos de Castro, 1965 only species in the area)

– Lateral plates on pleomere 5 normal ................................................................................................... .................................................. Anathelges ( A. hyptius ( Thompson, 1902) only species in the area)

5. Females usually greatly distorted (~ 90° or more), if not distorted with propodal sockets on pereo- pods............................................................................................................................ Asymmetrione 6

– Females scantily distorted (~ 70°) or nearly symmetrical, lacking propodal sockets on pereopods... ........................................................... Bopyrissa ( B. wolffi Markham, 1978 only species in the area)

6. Greater than 50º body asymmetry ..................................................................................................... 7

– Less than 50º body asymmetry ............................................ Asymmetrione desultor Markham, 1975

7. First pair of pereopods at both sides of head of similar size, pleopods 1–5 biramous ........................ ........................................................................................ Asymmetrione clibanarii * Markham, 1975

– First pair of pereopods at both sides of head clearly differs in size, pleopods 1–4 biramous and 5 uniramous ..................................................................................... Asymmetrione tuxtlaensis sp. nov.