Cloeon, Leach, 1815

Kluge, Nikita J., 2020, New subgenus Monilistylus subgen. n. and a new species Procloeon (Monilistylus) ornatipennis sp. n. (Ephemeroptera: Baetidae: Procloeon), Zootaxa 4742 (3), pp. 573-587 : 574-576

Cloeon /fg1

Branch «6»: Kluge & Novikova 1992: Fig. 11 .

Hierarchica name: Cloeon /fg1: Kluge 2012: 362.

Tribus Cloeonini: Kluge 2016: 492.

Diagnosis of Cloeon /fg1.

Larva. Both mandibles with dense setae between prostheca and mola ( Figs 4 , 18, 20 ). Labial palp with 3rd (distalmost) segment truncate ( Figs 26–27 ). On anterior side of tibia, proximal end of patella-tibial suture bent distally and connected under acute angle with row of long thin hairs ( Figs 30–31 ) (patella-tibial suture has equal structure on all legs – see Anteropatellata). Claw symmetric, slightly curved, with 2 similar rows of denticles ( Fig. 32 ); in some taxa without denticles. Abdominal segment IX and often one or several previous uromeres with longitudinal row of spines on each lateral margin ( Fig. 35 ). Tergalii often with anal-proximal expansion curved dorsally and forming a second (dorsal) lamella of tergalius; this lamella is absent in selected species of Procloeon /g1, including both species of Monilistylus ( Figs 9–15 ). Tergalii able to intensive rhythmic respiratory movements. Larval cerci and paracercus with dark rings on each 4th joining ( Fig. 8 ).

Subimago. All tarsomeres covered with pointed microlepides, without blunt microlepides. Process of posterodorsal angle of postsubalar sclerite diminished, pointed, with concave antero-dorsal margin ( Fig. 43 ) (unlike other Turbanoculata, in which this process is larger and has convex antero-dorsal margin).

Winged stages (imago and subimago). On fore wing each space with no more than 1 marginal intercalary ( Fig. 44 ). Hind wing, if present, of « Centroptilum - type »: relatively narrow and long, with hooked costal projection (in both species of Monilistylus hind wings absent).

Male genitals. Gonovectes fused by their median ends with penial bridge, unable for protraction ( Fig. 52 ). Gonostylus with 2nd segment thickened apically, 3rd (distalmost) segment clavate ( Figs 49 , 53 ). In mature larva ready to molt to subimago, subimaginal gonostyli folded under larval cuticle by « Cloeon - type »: 2nd segment directed laterally, 3rd segment curved either caudally ( Fig. 34 ), or caudally-medially.

Composition. Taxon Cloeon /fg1 includes Similicloeon Kluge & Novikova 1992 (= Intercloeon Kluge & Novikova 1992 ), Cloeon /fg2 (or genus Cloeon Leach 1815 s. str.), Waynokiops Hill, Pfeiffer & Jacobus 2010 , Pseudocentroptilum Bogoescu 1947 [with the single species P. unguiculatum Tshernova 1941 (= P. motasi Bogoescu 1947 )] and Procloeon /g1 (see below).

Figures

FIGURES 9–25. Details of larvae. 9–23, Procloeon (Monilistylus) ornatipennis sp. n.: 9–15, tergalii I–VII (holotype); 16, labrum; 17, maxilla (dorsal view); 18, right mandible; 19, its kinetodontium rotated after pressure of slide; 20, left mandible; 21–23, its incisor, kinetodontium and prostheca rotated after pressure of slide. 24–25, Procloeon (Monilistylus) monilistylus, kinetodontium and prostheca rotated after pressure of slide.

FIGURES 1–8. Larval exuviae. 1–2, Procloeon (Monilistylus) monilistylus: 1, right half of pro- and mesonotum; 2, thoracic sterna, pleura, metanotum, abdominal sterna and terga. 3–8, Procloeon (Monilistylus) ornatipennis sp. n.: 3, right half of pro- and mesonotum; 4, head; 5, thoracic sterna, pleura, metanotum and two legs; 6, abdominal sterna and terga (with caudalii of holotype); 7–8, caudalii of holotype, enlarged.

FIGURES 26–29. Procloeon (Monilistylus) ornatipennis sp. n., exuviae of labium: 26, general view with focus on ventral side; 27, labial palp with focus on dorsal side; 28, glossa and paraglossa with focus on ventral side; 29, the same with focus on dorsal side (26, holotype).

FIGURES 30–32. Procloeon (Monilistylus) ornatipennis sp. n., legs: 30, foreleg in anterior view (holotype); 31, base of tibia in anterior view; 32, claw.

FIGURES 33–38. Procloeon (Monilistylus) ornatipennis sp. n.: 33, larval exuviae of posterior margin of 9th abdominal sternum with protogonostyli; 34, subimaginal tissues with gonostyli, extracted from it; 35, exuviae of paraprocts and protogonostyli of another specimen; 36, exuviae of 5th abdominal sternum (Figs 33–36 under the same magnification); 37,middle of posterior margin of 9th abdominal tergum; 38, portion of mesonotum (magnification as in Fig. 37).Abbreviations: gs1, gs2, gs3, segments of gonostylus; m.gs, gonostylar muscle; m.gv, gonovectal (penial) muscle; m.s., lateral portion of styligeral muscle.

FIGURES 39–46. Procloeon (Monilistylus) ornatipennis sp. n.: 39–40, male imagines; 41, male imaginal genitals; 42, exuviae of right half of subimaginal mesonotum; 43, exuviae of left half of subimaginal mesopleuron; 44, wing; 45, abdominal terga II–VII; 46, tibia and tarsus of middle leg (41–43 and 45–46, holotype).

FIGURES 52–54. Procloeon (Monilistylus) monilistylus: 52–53, genital of male imago (corrected from Kluge et al. 2014); 54, exuviae of subimaginal gonostyli. Abbreviations: gs1, gs2, gs3, segments of gonostylus; m.gs, gonostylar muscle; m.gv, gonovectal (penial) muscle; m.s., median and lateral portions of styligeral muscle; usg, unistyliger.

FIGURES 47–51. Procloeon (Monilistylus) ornatipennis sp. n. (holotype): 47, median projection of penis; 48, exuviae of subimaginal gonostyli; 49, genitals with all visible muscles (muscles and hidden parts of penis shown by interrupted lines); 50, the same with penis, its muscles and gonoducts (shown by dotted line); 51, the same with muscles of styliger (penis not shown). Abbreviations: gs1, gs2, gs3, segments of gonostylus; m.IX-X, area of attachment of intersegmental paraproctal muscle; m.gs, gonostylar muscle; m.gv, gonovectal (penial) muscle; m.s., lateral portion of styligeral muscle; usg, unistyliger.