Apobaetis, Day, 1955

Cruz, Paulo Vilela, 2020, Redescription of three species of Apobaetis Day, 1955 (Ephemeroptera: Baetidae), Zootaxa 4808 (2), pp. 317-330 : 328-329

Key to the identification of the larvae of the Apobaetis species described to date

(adapted from Nieto 2006 and Cruz & De-Souza 2014)

1. Third segment of labial palp completely triangular (Figs 12, 25 and 37 in Nieto 2006), with only one apical corner; distal margin of labrum near midline without blunt setae ( Figs 6B , 19 and 31 in Nieto 2006)..................................... 2

1’. Third segment of labial palp subtriangular or subquadrangular, with two lateral corners ( Figs 2F , 4F and 6F ); distal margin of labrum near midline with blunt setae ( Figs 2A , 4A and 6A ).................................................... 5

2. Segment II of labial palp with strongly rounded distomedial projection ( Fig. 5 in McCafferty 2000); segment II of maxillary palp robust and thick ( Fig. 4 in McCafferty 2000)........................................ A. lakota [North America]

2’. Segment II of labial palp without strongly rounded distomedial projection ( Figs 2F , 4F and 6F ); segment II of maxillary palp robust and thin ( Figs 2E , 4E and 6E )...................................................................... 3

3. Maxillary palp long, at least 1.5× length of galea-lacinia (Fig. 35 in Nieto 2006); dorsal margin of femora with blunt setae (Fig. 38 in Nieto 2006)...................................................................... A. niger Nieto 2006

3’. Maxillary palp shorter, subequal to galea-lacinia (Fig. 23 in Nieto 2006); dorsal margin of femora without blunt setae (Fig. 26 in Nieto 2006)........................................................................................ 4

4. Labrum with pronounced medial emargination ( Fig. 6a in Nieto 2006); segment II of labial palp with distomedial projection, rounded apically (Fig. 12 in Nieto 2006)................................................. A. insolitus Nieto 2006

4’. Labrum with shallow medial emargination (Fig. 19 in Nieto 2006); segment II of labial palp with distomedial projection pointed apically (Fig. 25 in Nieto 2006)................................................ A. kallawaya Nieto 2006

5. Tarsal claws longer than tarsi (Figs 10A and 22 in Cruz & De-Souza 2014).........................................6

5’. Tarsal claws shorter than tarsi ( Figs 3A , 5A and 7A ).......................................................... 8

6. Segment III of labial palp subquadrangular ( Figs 2F , 4F and 6F ); abdominal tergum V with lateral mark................ 7

6’. Segment III of labial palp subtriangular (Fig. 16 in Cruz et al. 2011); abdominal tergum V with medial mark................................................................................ A. hamadae Cruz, Boldrini & Salles 2011

7. Segment II of maxillary palp without constriction ( Fig. 7 in Cruz & De-Souza 2014); segment II of labial palp with straight distomedial projection (Fig. 9 in Cruz & De-Souza 2014); paraproct with four marginal spines (Fig. 12 in Cruz & De-Souza 2014)................................................................... A. kethepiali Cruz & De-Souza 2014

7’. Segment II of maxillary palp with constriction (Fig. 19 in Cruz & De-Souza 2014); segment II of labial palp with pointed distomedial projection (Fig. 21 in Cruz & De-Souza 2014); paraproct with one pointed marginal spine (Fig. 24 in Cruz & De-Souza 2014)........................................................................................ A. pucupi

8. Segment II of maxillary palp without apical constriction ( Figs 4F and 6E )........................................ 9

8’. Segment II of maxillary palp with apical constriction ( Fig. 2E )............................ A. etowah [North America]

9. Labrum, distal margin with short and blunt setae near midline ( Fig. 6A ); maxillary palp long, 1.28× length of galea-lacinia ( Fig. 6E ); abdominal tergum V has a single lateral dark mark ( Fig. 1C )........................................ A. signifer

9’. Labrum, distal margin with elongated and blunt setae near midline ( Fig. 4A ); maxillary palp long, 1.5× length of galea-lacinia ( Fig. 4E ); abdominal terga II, III, V, VI and IX are darker ( Fig. 1A )........................................ A. fiuzai

Figures

FIGURE 1. Dorsal habitus. A. Apobaetis fiuzai holotype; B. Apobaetis fiuzai, abdominal details of a paratype; C. Apobaetis signifer holotype; D. Apobaetis signifer, abdominal detail of the holotype.

FIGURE 2. Apobaetis etowah. A. labrum (left d.v., right v.v.); B. right mandible; C. left mandible; D. hypopharynx; E. maxilla; F. labium (left d.v., right v.v.).

FIGURE 3. Apobaetis etowah. A. foreleg; B. detail patella-tibial suture, red arrow indicates the location of suture; C. posterior margin of tergum IV; D. paraproct.

FIGURE 4. Apobaetis fiuzai. A. labrum (left d.v., right v.v.); B. right mandible; C. left mandible; D. hypopharynx; E. maxilla; F. labium (left d.v., right v.v.).

FIGURE 5. Apobaetis fiuzai. A. foreleg; B. posterior margin of tergum IV; C. paraproct.

FIGURE 6. Apobaetis signifer. A. labrum (left d.v., right v.v.); B. right mandible; C. left mandible; D. hypopharynx; E. maxilla; F. labium (left d.v., right v.v.).

FIGURE 7. Apobaetis signifer. A. foreleg; B. detail patella-tibia suture, red arrow indicates the location of suture; C. posterior margin of tergum IV; D. paraproct.