Lasiognathus

KEY TO FEMALES OF THE SPECIES OF LASIOGNATHUS

1 a. Escal hooks borne on a short, transverse, fanshaped, distal appendage (Bertelsen and Pietsch, 1996: 404, fig. 2) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Lasiognathus beebei Regan and Trewavas, 1932

1 b. Escal hooks borne on an elongate, cylindrical, distal appendage _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2

2 a. Escal bulb with a membranous anterior crest; prolongation of distal appendage absent (Bertelsen and Pietsch, 1996: 404, fig. 3) _ _ _ _ _ _ _ _ _ Lasiognathus waltoni Nolan and Rosenblatt, 1975

2 b. Escal bulb without a membranous anterior crest; prolongation of distal appendage present _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3

3 a. A cylindrical, internally pigmented, anterior escal appendage arising from base of escal bulb; distal escal appendage with a pair of slender, filamentous prolongations (Figs. 2, 3) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Lasiognathus dinema Pietsch and Sutton, new species

3 b. Cylindrical, internally pigmented, anterior escal appendage absent; distal escal appendage with a single cylindrical or compressed prolongation _ _ _ _ _ _ 4

4 a. Distal escal appendage with a short, cylindrical prolongation (length 5.2–8.6 % SL) emerging ante- riorly from bases of escal hooks, without lateral serrations or filaments; posterior escal appendage cylindrical (Bertelsen and Pietsch, 1996: 405, fig. 4) _ _ _ _ _ _ _ _ _ Lasiognathus intermedius Bertelsen and Pietsch, 1996

4 b. Distal escal appendage with an elongate, com- pressed prolongation (length 2.9–20.8 % SL) emerg- ing anteriorly from bases of escal hooks, bearing lateral serrations and/or tiny filaments on distal tip; posterior escal appendage broad, laterally compressed _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5

5 a. Three darkly pigmented escal hooks; length of distal escal appendage 8.0– 12.5 % SL (in specimens ranging from 30–77 mm); length of prolongation of distal escal appendage increasing with standard length from 7.7 % SL (in 30 mm specimen), to 10.8 % SL (55.5 mm), to 20.8 % SL (77 mm); prolongation of distal escal appendage bearing numerous lateral serrations and distal filaments (Bertelsen and Pietsch, 1996: 407, fig. 5) _ _ _ _ _ _ _ _ _ _ _ _ Lasiognathus saccostoma Regan, 1925

5 b. Two lightly pigmented escal hooks; length of distal escal appendage 3.8 % SL (in a 157 mm specimen); length of prolongation of distal escal appendage 2.9 % SL (in 157 mm holotype); prolongation of distal escal appendage without lateral serrations, but bearing a series of six tiny distal filaments (Pietsch, 2005: 78, figs. 1, 2) _ _ _ _ _ _ _ _ _ _ _ _ Lasiognathus amphirhamphus Pietsch, 2005