Key to the species in the genus Austrolimnius Carter & Zack from Mexico and Central America.

1 – Pronotum with a medial longitudinal sulcus (Fig. 1A) ( Telmatelmis)............................................. 2

1' – Pronotum smooth, without a medial longitudinal sulcus................................... A. (Helonoma) eris Hinton

2 – Elytron with a carina at base of third interval (Figs. 1A, 1C)................................................... 3

2' – Elytron without a carina at base of third interval.............................................. A. formosus (Sharp)

3 – Pronotum with median sulcus about 3/4 as wide at apex as at base; males with tuff of golden setae on prosternum, behind base of prosternal process, and tuff on side of metasternal disk, behind middle coxa....................... A. halffteri Hinton

3' – Pronotum with median sulcus almost as wide at apex as at base (Fig 1A) or almost twice as wide at apex as at base; males without tuffs of setae on prosternum and on side of metasternal disk (e.g., Fig. 1B)................................. 4

4 – Pronotum with median sulcus almost twice as wide at apex as at base; elytron with long carina at base of third interval, reaching almost 1/4 of elytron length............................................................... A. curtulus (Sharp)

4' – Pronotum with sulcus almost as wide at apex as at base (Fig. 1A); elytron with short carina at base of third interval, reaching only 1/8–1/10 of elytron length (e.g., Figs. 1A, 1C).......................................................... 5

5 – Male hind trochanter with row of teeth on posterior margin; hind tibiae with preapical denticle on internal margin and without oval concavity on dorsal margin.......................................................... A. sulcicollis (Sharp)

5' – Male hind trochanter without row of teeth on posterior margin (Fig. 1A); hind tibiae without preapical denticle on internal margin and with oval concavity on dorsal margin (Fig. 1A, encircled detail)....... A. hintoni Arce-Pérez & Reynoso sp. nov.