Choroterpes (Afrochoroterpes), Kluge, 2025

Kluge, Nikita J., 2025, Redescriptions of Choroterpes nigrescens Barnard 1932 and Ch. ndebele Agnew 1962 with notes about egg structure of Choroterpes Eaton 1881, Megaglena Peters & Edmunds 1970 and Klugephlebia Selvakumar et al. 2016 (Ephemeroptera, Leptophlebiidae), Zootaxa 5711 (2), pp. 203-222 : 204

Afrochoroterpes subgen. nov.

( Figs 1–98 )

Type species: Choroterpes nigrescens Barnard 1932 .

Diagnosis. Differs from all other taxa by unique structure of eggs: egg is elongated and narrowed, spindle-shaped ( Figs 84 , 90 ); chorion is armed with hidden longitudinal ladder-like structures running from one pole to another; the ladder-like structure consists of a pair of rigid rods connected by fine transverse anastomoses ( Figs 85 , 95 ); these anastomoses are hidden in a longitudinal groove ( Figs 90–91 ), so that can be invisible under scanning electron microscope ( Fig. 84 ). By such egg structure, Afrochoroterpes sharply differs from all other Choroterpes s. l., which have the « Choroterpes - type » egg structure (see below and Figs 99–100 ). The rods of ladder-like structures can be either straight ( Fig. 85 ), or undulate ( Fig. 95 ); other details of egg structure also differ in Choroterpes ( Afrochoroterpes) nigrescens ( Figs 84–89 ) and Ch. ( A.) ndebele ( Figs 90–98 ) (see below).

Middle process of larval tergalii II–VII (one of three apical processes of each two lamellae characteristic for Choroterpes s. l.) is narrow at base and more or less widened at middle ( Figs 44–49, 51–56 , 58–63, 65–70 ). The same in subgenera Choroterpes s. str. and Neochoroterpes, in contrast to Euthraulus , Cryptopenella and Dilatognathus , in which the middle process is always narrowing from base to apex.

Composition. Two species, Choroterpes ( Afrochoroterpes) nigrescens Barnard 1932 and Choroterpes ( Afrochoroterpes) ndebele Agnew 1962 .

Distribution. South Africa. All known Afrotropical representatives of the genus Choroterpes s. l. belong to subgenera Euthraulus and Afrochoroterpes .

Figures

FIGURES 1–10. Choroterpes (Afrochoroterpes) nigrescens. 1–5, larval exuviae (1, half of pronotum and mesonotum; 2, abdomen; 3–5, fore, middle and hind legs); 6, abdomen of male imago; 7, abdomen of female imago; 8, larva; 9–10, fore and hind legs of male imago.

FIGURES 11–19. Choroterpes (Afrochoroterpes) ndebele. 11–15, larval exuviae (11, half of pronotum and mesonotum; 12, abdomen; 13–15, fore, middle and hind legs); 16, abdomen of male imago; 17, hind leg of male imago; 18–19, fore and hind legs of larva.

FIGURES 20–27. Larval mouthparts. 20–21, Choroterpes (Afrochoroterpes) nigrescens (20, labrum; 21, left mandible); 22–27, Choroterpes (Afrochoroterpes) ndebele (22–24, labrum; 25, left mandible; 26, maxilla; 27, labium).

FIGURES 28–35. Choroterpes (Afrochoroterpes) nigrescens, larval exuviae. 28, hind femur, focus on anterior side; 29, the same, focus on posterior side; 30–32, fore, middle and hind tibiae, focus on anterior side; 33, hind tibia, focus on posterior side; 34–35, posterior margins of abdominal terga V and IX.

FIGURES 36–42. Choroterpes (Afrochoroterpes) ndebele, larval exuviae. 36, hind femur, focus on anterior side; 37, the same, focus on posterior side; 38–40, fore, middle and hind tibiae, focus on posterior side; 41, the same, enlarged. 42, posterior margin of abdominal tergum V.

FIGURES 43–56. Choroterpes (Afrochoroterpes) nigrescens. 43–49 and 50–56, tergalii of I–VII pairs of two individuals.

FIGURES 57–70. Choroterpes (Afrochoroterpes) ndebele. 57–63 and 64–70, tergalii of I–VII pairs of two individuals.

FIGURES 71–75. Wings. 71–74, Choroterpes (Afrochoroterpes) ndebele: 71–72, fore and hind wings of male imago; 73, enlarged hind wing; 74, hind wing of female developing in larval protopteron; 75, Choroterpes (Afrochoroterpes) nigrescens, hind wing of male imago.

FIGURES 76–83. 76–80, Choroterpes (Afrochoroterpes) nigrescens: 76, genitalia of male imago; 77, subimaginal exuviae of genitalia; 78, penis of male imago; 79, subimaginal exuviae of right half of mesonotum; 80, larval exuviae of protogonostyli and protopenis; 81–83, Choroterpes (Afrochoroterpes) ndebele: 81, genitalia of male imago; 82, penis of male imago; 83, larval exuviae of protogonostyli and protopenis. Abbreviations: acz, achromozones of medioscutum and submedioscutum; cz, chromozones of medioscutum and submedioscutum.

FIGURES 84–89. Eggs of Choroterpes (Afrochoroterpes) nigrescens. 84, under scanning electron microscope; 85–89, after treating by lactic acid, in transmitted light in glycerin: 85, detached chorion; 86, optic section; 87–89, surface view.

FIGURES 90–98. Eggs of Choroterpes (Afrochoroterpes) ndebele. 90–91, under scanning electron microscope; 92–98, after treating by lactic acid, in transmitted light: 92, detached chorion in Canadian balsam; 93–96, one and the same fragment of chorion: 93–94, in Canadian balsam, focus on external and internal sides; 95–96, in glycerin, focus on external and internal sides; 97, optic section in glycerin; 98, surface view in glycerin. Abbreviations: pap, papilla; ves, vesicle.

FIGURES 99–104. Eggs of «Choroterpes-type». 99, Choroterpes (Choroterpes) picteti picteti; 100, Choroterpes (Choroterpes) picteti subcostalis; 101–102, Megaglena brincki; 103–104, Klugephlebia kodai.