Procloeon (Oculogaster), Kluge 2016

Kluge, Nikita J., 2020, Review of Oculogaster Kluge 2016 (Ephemeroptera, Baetidae, Procloeon Bengtsson 1915), Zootaxa 4820 (3), pp. 401-437 : 402-403

Oculogaster Kluge 2016

( Figs 1–133 )

Subgenus Oculogaster Kluge 2016: 494 .

Type species: Procloeon cylindroculum Kimmins 1956 .

Diagnosis. (1) Viviparous ( Kluge 2016: figs 38–42, 76–79). The same in Cloeon s. str. and some other mayflies, but not in other Procloeon /g1. (2) Pterostigma normally either with 1 cross vein ( Fig. 40 ), or with 2 cross veins ( Fig. 104 ) (on individual wings this number varies from 1 to 3) ( Figs 40–41 ). (3) Larval femur with two apical spine-like setae ( Figs 17 , 81 , 110 ). The same in many other taxa of Baetidae , but not in other Procloeon /g1 and not in other Cloeon /fg1.

Larvae of all Oculogaster have a similar structure of the labium, with a pair of submedian setae distinguishable among other setae of dorsal surface ( Figs 50 , 113 ). Mandibles of the « Baetis - type » ( Kluge 2020a: table 1 and p. 578), i.e. with incisor and kinetodontium fused, left prostheca wide, and all denticles of incisor, kinetodontium, prostheca and mola visible in one view ( Figs 51–52 , 114–115 ). All species of Oculogaster lack hind wings, and larvae have no vestiges of hind protoptera ( Müller-Liebenau & Hubbard 1985: fig. 9h).

Distribution. Paleotropical (Afrotropical and Oriental Regions).

Discussion. In the previous diagnosis, the number of cross veins in pterostigma was reported as one, with individual variability; this diagnosis was based on P. (O.) cylindroculum and P. (O.) album , whose pterostigma normally has one cross vein. Examination of P. regularum reveals that it should be placed in Oculogaster , while its pterostigma normally has 2 cross veins; this fact expands the diagnosis of Oculogaster . While pterostigma with one cross vein is not found in any taxa other than Oculogaster , pterostigma with two veins occurs in some other taxa, particularly in some species of Cloeon s. str., which were confused with species belonging to Oculogaster .

Species composition and classification. Oculogaster can be divided into two species groups: the African group, which includes P. (O.) cylindroculum Kimmins 1956 , P. (O.) barnardi sp. n., P. (O.) niger sp. n., P. (O.) sp. «Wolfkloof» and presumably P. (O.) silvicola Gillies 1997 , and the Asian group, which includes P. (O.) album Kluge 2016 , P. (O.) regularum Müller-Liebenau & Hubbard 1985 , P. (O.) malabarensis sp. n., presumably P. julia ( Gillies 1949) comb. n. and unnamed P. sp. «Thailand-3», P. sp. «Sulawesi» and P. sp. « Philippines ».

Figures

FIGURES 1–7. Procloeon (Oculogaster) barnardi sp. n. 1–6, male larva ready to moult to subimago: 1–2, larval cuticle detached from thorax and abdomen; 3, fragment of abdomen (arrows show bases of bifurcate setae similar to Fig. 48); 4, intact specimen (IV–IX, abdominal segments); 5, extracted subimaginal thorax; 6, extracted subimaginal abdomen; 7, same, female.

FIGURES 8–16. Larvae of Procloeon (Oculogaster) barnardi sp. n. 8–9, caudalii; 10–15, exuviae of abdomen and pronotum with mesonotum of three specimens (14–15, holotype); 16, young larva.

FIGURES 17–18. Larva of Procloeon (Oculogaster) barnardi sp. n., middle leg. 17, apex of femur and base of tibia, anterior view (patella-tibial suture and bases of fine setae are visible as light markings on darker background); 18, more distal part of tibia, posterior view (with continuation of patella-tibial suture visible as light line).

FIGURES 19–29. Larvae of Procloeon (Oculogaster) barnardi sp. n. 19–25, tergalii I–VII; 26–27, tergalii V of other specimens; 28, tergalius VII of another specimen; 29, claw (holotype).

FIGURES 30–33. Male Procloeon (Oculogaster) barnardi sp. n. (holotype). 30–31, imago; 32, exuviae of subimaginal mesonotum; 33, exuviae of subimaginal pleuron.

FIGURES 34–35. Male Procloeon (Oculogaster) barnardi sp. n. (holotype). 34, genitalia of imago (penis dotted; gonostylar muscle not shown at right, penial muscles not shown at left); 35, their subimaginal exuviae.

FIGURES 36–42. Female Procloeon (Oculogaster) barnardi sp. n. 36–39, imagines; 40–41, veins of pterostigma; 42, hind tarsus of subimago.

FIGURES 43–48. Larval exuviae of Procloeon (Oculogaster) niger sp. n. 43–44, caudalii; 45, abdomen; 46, half of pronotum and mesonotum; 47, male uromeres IX–X; 48, fragment of abdominal tergum VIII (arrow shows long bifurcate seta near midlength) (43–46, holotype).

FIGURES 49–56. Larva of Procloeon (Oculogaster) niger sp. n. (holotype): 49–50, labrum with focus on ventral and dorsal sides; 51–52, left and right mandibles; 53–54, maxilla (ds1–ds3, dentisetae); 55–56, labium with focus on dorsal and ventral sides.

FIGURES 57–66. Larvae of Procloeon (Oculogaster) niger sp. n. 57–62, tergalii I–III and V–VII; 63–65, tergalii I, IV and VII of other specimens (64–65, holotype); 66, claw.

FIGURES 67–70. Male Procloeon (Oculogaster) niger sp. n. 67–68, male imagines; 69, subimaginal exuviae of postsubalar sclerite; 70, subimaginal exuviae of mesonotum (67, 69, holotype).

FIGURES 71–72. Male Procloeon (Oculogaster) niger sp. n. 71, genitalia of imago (penis dotted; gonostylar muscle not shown at right, penial muscles not shown at left); 72, their subimaginal exuviae.

FIGURES 73–77. Female Procloeon (Oculogaster) niger sp. n. 73–74, imago; 75, imaginal abdomen; 76–77, subimaginal exuviae of fore and middle tarsi (arrows show spines; 1st–5th, initial tarsomeres).

FIGURES 78–83. Procloeon (Oculogaster) sp. «Wolfkloof». 78–79, larval exuviae of abdominal terga, pronotum and mesonotum; 80, subimaginal abdomen; 81, larval hind leg with subimaginal leg inside (arrows show spines on subimaginal tarsus); 82, claw; 83, apex of wing extracted from larva.

FIGURES 84–89. Larvae of Procloeon (Oculogaster) regularum. 84–88, exuviae: 84, abdomen; 85–86, its caudalii; 87–88, fragment of middle part of cercus, with focus on lateral and median sides; 89, male larva.

FIGURES 90–98. Procloeon (Oculogaster) spp. 90–97, P. (O.) regularum: 90–96, tergalii I–VII; 97, genitalia of male imago (penis dotted, muscles not shown). 98, tergalius IV of Procloeon (Oculogaster?) sp. «Philippines».

FIGURES 99–102. Male imagines of Procloeon (Oculogaster) regularum. 99–101, general view; 102, abdominal tergum IV.

FIGURES 103–108. Females of Procloeon (Oculogaster) regularum. 103–104, imagines; 105–108, subimaginal exuviae: 105–106, middle and fore tarsi (arrows show spines; 1st–5th, initial tarsomeres); 107, half of mesonotum; 108, mesothoracic pleuron.

FIGURES 109–112. Larvae of Procloeon (Oculogaster) malabarensis sp. n. 109, mature male larva (arrows show reddish hypodermal markings on abdominal terga VI and VII); 110, fragment of fore leg, focus on anterior side; 111, claw; 112, caudalii (110, 112, holotype).

FIGURES 113–117. Larva of Procloeon (Oculogaster) malabarensis sp. n. (holotype). 113, labrum (focus on dorsal side); 114–115, left and right mandibles; 116, maxilla; 117, labium (at left focus on dorsal side, at right focus on ventral side).

FIGURES 118–126. Procloeon (Oculogaster) malabarensis sp. n. 118–124, tergalii I–VII (holotype); 125, genitalia of male imago (muscles not shown); 126, their subimaginal exuviae.

FIGURES 127–133. Procloeon (Oculogaster) malabarensis sp. n. 127, abdominal terga III–V of male imago; 128–129, male imagines; 130, subimaginal exuviae of mesothoracic pleuron; 131, female imago; 132–133, abdomina of female imagines (133, holotype).