Macrothemis hemichlora (Burmeister, 1839)

Salgado, Luiz Gustavo Vargas, Carvalho, Alcimar Do Lago & Pinto, Ângelo Parise, 2013, Larval taxonomy of Macrothemis Hagen, 1868 (Odonata: Libellulidae), with descriptions of four larvae and a key to the fourteen known species, Zootaxa 3599 (3), pp. 229-245 : 238

Macrothemis hemichlora (Burmeister, 1839)

( Figures 21–29 )

Material. BRAZIL, Rio de Janeiro State: Maricá municipality, Rio Ubatiba [22º52’17.22’’S, 42º47’ 00.84’’W; 36 m a.s.l.], 24.V.2000, Equipe Entomologia UFRJ leg., ̩ F-0, adult emergence 04.VI.2000. Deposited in DZRJ.

Larva very similar to M. imitans imitans described above, differing by the following features:

Posterior areas of head and thorax with short setae flattened apically.

Head ( Figs. 21–25 ). About 2.5x as wide as long in dorsal view; occipital lobes covered with short flattened and long filiform setae. Vertex with short filiform setae, not especially concentrated. Occiput bearing short robust setae flattened distally. Lateral portion of eyes rather pronounced forward and laterally. Proportional length of antennomeres: 60, 87, 100, 65, 90, 86, 70. Mandibular formula L 12’234 abb’ / R 1234 y- abd ( Figs. 21–22 ); left mandible: molars and incisors 1 and 4 with obtuse apex, 2’2 and 3 with acute apex, size bb’>a, size 3>4>1>2, prominence 3>4>2>1; right mandible: molars a and d and incisors 1–3 with acute apex, b and 4 obtuse, size b>d>a, size 4>1>3>2, prominence 4>3>2>1, y- acute. Labium when folded reaching level between pro- and mesocoxae; prementum longer than width in ventral view; ligula projected 0.25, forming an angle of about 100º ( Fig. 23 ); margin of ligula bearing a submarginal row of about 30 setae, with about 10 of these distinctly larger; premental setae 7–8; external margins of prementum bearing a row of about 10 short and robust setae. Labial palps with 5 palpal setae ( Fig. 24 ); proximal portion with setella and a group of 6–8 short spiniform setae; proximal 0.66 of outer margin with a row of about 11–12 short and robust setae; distal margin with 9 crenations ( Fig. 25 ); central crenations with 3–5 setae, 1–3 in those closest to outer margin; inner margin with a row of about 12–17 setae; ventral surface of palps with small dark spots not coincident with setae insertion.

Thorax. Pronotum with short setae; posterolateral margins with short robust setae distally flattened; inverted “V” spot barely visible in the only examined exuvia.

Abdomen ( Figs. 26–29 ). Tergites with spiniform setae of lateral margins equally distributed along abdomen ( Figs. 26–27 ); lateral spines on S8–9, as long as 0.7 and 0.8 mediodorsal length of respective segment. Cerci ca. 0.8 of epiproct length in lateral view ( Figs. 28–29 ); apex of cerci straight.

Measurements (in mm; n=1). Total length 14.22; head mediodorsal length 1.85; head max. width 4.35; antenna total length 1.40; length of antennomeres 0.15, 0.22, 0.25, 0.16, 0.23, 0.22, 0.17; prementum length 3.37; prementum maximum width 3.05; hind wing sheath length 4.73; metafemur length 3.06; metatibia length 4.00; abdomen length (incl. appendages) 7.12; abdomen max. width (S6) 5.20; epiproct length in lateral view 0.81; paraproct max. length in lateral view 0.76; cercus length in lateral view 0.65.

Diagnosis. The F-0 larva of M. hemichlora can be correctly identified as Macrothemis in the majority of the keys examined, except that of Rodríguez Capítulo (1992) ( Tables 1–2). The following combination of characters separates it from the other described larvae of the genus: antennomeres 5–7 distinctly longer than half of 3; ligula moderately prominent, with lateral margins forming an angle of ca. 100o ( Fig. 15 ); premental setae 7–8; rows of premental setae not clearly divided in two groups; labial palps with semicircular crenations, notches deep (regular type) ( Figs. 13–14 ); 5 palpal setae; setae of distal margin of labial palps cylindrical; dorsal hooks on S3–9 ( Figs. 7–8 ); dorsal hook on S5 not reduced, larger than those of preceding segments; dorsal hook of S9 shorter and less pronounced distally than corresponding lateral spines in dorsal view; lateral spines of S9 straight.

Figures

FIGURES 21 – 29. Macrothemis hemichlora (Burmeister, 1839), ultimate stadium larva, 3: 21. right mandible, inner view; 22. left mandible, inner view; 23. right labial palp, dorsal view; 24. distal border of right labial palp, ventral view; 25. prementum, dorsal view; 26. abdomen, dorsal view; 27. abdomen, lateral view; 28. caudal appendages, dorsal view; 29. caudal appendages, lateral view.

FIGURES 11 – 20. Macrothemis declivata Calvert, 1909, ultimate stadium larva, 3: 11. right mandible, inner view; 12. left mandible, inner view; 13. right labial palp, dorsal view; 14. distal border of right labial palp, ventral view; 15. prementum, dorsal view; 16. abdomen, dorsal view; 17. abdomen, lateral view; 18. abdominal segment 9, ventral view; 19 caudal appendages, dorsal view; 20. caudal appendages, lateral view.

FIGURES 1 – 10. Macrothemis imitans imitans Karsch, 1890, ultimate stadium larva, 3: 1 head, dorsal view; 2. right mandible, inner view; 3. left mandible, inner view; 4. right labial palp, dorsal view; 5. distal border of right labial palp, ventral view; 6. prementum, dorsal view; 7. abdomen, dorsal view; 8. abdomen, lateral view; 9. caudal appendages, dorsal view; 10. caudal appendages, lateral view. “ a ” and “ b ”, measurements used to represent the projection of ligula.