Procloeon (Monilistylus) ornatipennis, Kluge, 2020

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 : 580-586

Procloeon (Monilistylus) ornatipennis sp. n.

( Figs 3–23 , 26–51 )

Material examined. Holotype: L-S-I ♂ {specimen [XL](4)B2009}, INDONESIA, Lombok , Senaru, 26.IX.2009, coll. N.Kluge & L. Sheyko. Paratypes: the same place, date and collectors, 2 L-S-I ♂, 1 mature male larva.

Descriptions. Larva. CUTICULAR COLORATION. Head, thorax (terga, pleura and sterna of pro-, meso- and metathorax) and abdominal terga with species-specific pattern of darker and lighter brown and ocher areas ( Figs 3–6 ); abdominal sterna mostly light with anterior margins slightly darkened. Each femur mostly light, with brown macula in distal part; each tibia mostly light, diffusively shed with brown at base and at apex; each tarsus mostly light, shed with brown on outer side ( Fig. 30 ). Cerci and paracercus light, with brown ring on each 4th joining ( Fig. 8 ).

HYPODERMAL COLORATION. Not expressed.

SHAPE AND SETATION. Frontal suture acute-angled ( Fig. 4 ). Dorsal surface of labrum with long, irregularly situated setae ( Fig. 16 ). Mandibles with incisor and kinetodontium deeply separated ( Fig. 4 ). Left mandible: incisor terminated by 4 denticles; kinetodontium terminated by 3 denticles and rotated perpendicular to mandible flatness; prostheca bifurcate and rotated perpendicular to mandible flatness ( Figs 20–23 ). Right mandible: incisor terminated by 3 denticles; kinetodontium rotated perpendicular to mandible flatness and terminated by 2 denticles, with one side denticle; prostheca slender and single-pointed ( Figs 18–19 ). Maxilla with all 3 canines and 3 dentisetae long and pointed; maxillary palp long and 3-segmented, with 3rd segment longer than 2nd ( Fig. 17 ). Labium: Glossa with numerous stout, short setae in longitudinal dorso-median and dorso-lateral rows ( Fig. 29 ); ventral side with numerous long, irregularly situated setae ( Fig. 28 ). Paraglossa with numerous long setae forming longitudinal dorso-median and ventro-median rows and irregularly situated setae on dorsal, ventral and lateral sides ( Figs 28–29 ). Labial palp with 3rd segment wide and truncate, with irregularly situated fine setae on ventral side and on distal margin and with 2 regular rows of stout pointed setae along distal margin ( Fig. 27 ).

Pronotum, mesonotum, metanotum and thoracic pleura with minute protuberances ( Fig. 38 ). Metanotum without vestiges of hind protoptera ( Fig. 5 ). Femur without stout setae on outer side, with irregularly situated pointed setae on inner side ( Fig. 30 ); apex of femur without stout setae ( Fig. 31 ). Tibia with stout pointed setae on inner side only; outer-apical seta absent on all legs. Tarsus as long as tibia, with numerous pointed setae on inner side only. Claw long and sender, with 2 rows of denticles reaching midlength of claw; denticles very dense and slender; denticles of various length and thickness irregularly alternate ( Fig. 32 ).

Abdominal segments VIII and IX with lateral denticles. Posterior margin of abdominal tergum I with few very small denticles; posterior margins of terga II–X with long, pointed denticles irregularly alternated with smaller ones; no median interruption on tergum IX ( Fig. 37 ). Posterior margins of abdominal sterna I–IV without denticles, of sternum V with few small denticles, of sterna VI–IX with long, pointed denticles ( Fig. 35 ). All abdominal terga and sterna with numerous triangular scales ( Fig. 37 ); sterna, besides this, with long simple (not bifurcate) setae, evenly dispersed on sterna and forming a transverse row on posterior margin of sterna I–VII ( Fig. 36 ). Paraprocts with numerous slender, pointed spines directed caudally ( Fig. 35 ).

Tergalii ( Figs 9–15 ): Tergalius I petiolate, with costal margin nearly straight and anal margin sharply convex, widest near midlength; tergalii II–VI with gradually changing shape: tergalius II with costal margin nearly straight and anal margin sharply convex, widest proximally; tergalius VI roundish; tergalius VII semicircular. Costal rib colorless, smooth, without serration or setation; absent on tergalius I, gradually elongated on tergalii II–VII. Anal rib narrow and pigmented; absent on tergalius I, borders the concave margin of tergalii II–VI, longest on tergalius VII. The tergalii I–VI crossed by irregular, oblique folds; tracheae proximad and distad of this fold with dark brown granulation, on fold colorless.

Primary swimming setae of cerci and paracercus with proximal parts rigid and brown, distal parts delicate and colorless. In proximal part of cercus each cercomere with several pointed spines; in distal part of cercus each cercomere with one very long and thick spine on outer side ( Fig. 7 ) [see Procloeon /g1 (1)]. Cercus with slender apical portion lacking median swimming setae and lateral spines ( Fig. 8 ).

RESPIRATORY MOVEMENTS. Tergalii able to make rhythmic respiratory movements.

Subimago, male. CUTICULAR COLORATION. Head colorless, with antennae brownish. Pronotum light brownish with colorless sigilla. Mesonotum with contrasting brown and colorless areas ( Fig. 42 ). Thoracic pleura and sterna mostly colorless, with certain sclerites brown ( Fig. 43 ). Legs light brownish. Abdominal terga light brownish, without contrasting sigilla; sterna nearly colorless. Cerci and gonostyli light brownish.

TEXTURE. On legs of all pairs all tarsal segments covered by pointed microlepides, only small basal part of first tarsomere covered by microtrichiae (as tibia and other leg segments).

Imago, male. COLORATION ( Figs 39–40 ). Head mostly ocher. Turbinate eyes with facetted surface ocherorange. Fore wing with brown maculae on each cross vein, on pterostigma and on apex of each convex longitudinal vein from RA to MP ( Fig. 44 ). Legs light ocher, with apex of femur diffusively brownish darkened. Abdomen light ocher; terga II, III and V with brown markings consisting of s median stripe and s pair of lateral, oblique spots ( Fig. 45 ). Cerci uniformly ocher.

STRUCTURE. Turbinate eyes sharply widened ( Figs 39–40 ). Hind wings absent. Middle and hind legs with first tarsal segment (initial 1st+2nd segments) very long and slender, without apical spine ( Fig. 46 ). In holotype, relation of fore femur to fore wing length 48:230; proportions femur/tibia/tarsomeres on fore leg 48:71:2:35:25:12:8, on middle and hind legs 44:37:17:5:2:6.

MALE GENITALS. Median projection between unistyligers trapezoid, non-sclerotized ( Fig. 51 ). Penis medially with triangular projection terminated by narrow, sclerotized, finger-like tip ( Fig. 47 ). First segment of gonostylus short, with prominent pointed outgrow projected medially-distally; second segment grooved in proximal part [see Monilistylus (2)]; third (apical) segment markedly elongated both in imago ( Fig. 49 ), subimago ( Fig 48 ) and even in larva ( Figs 33–34 ). Styligeral muscle with median portion short, not reaching bases of unistyligers; lateral portions of styligeral muscle divergent, much longer than median portion, attached at bases of unistyligers ( Fig. 51 ) [see Monilistylus (1)].

Female and eggs. Unknown.

Dimensions. Fore wing length (and body length) 6.5 mm.

Comparison. Imago of the new species Procloeon (Monilistylus) ornatipennis sp. n. differs from Procloeon (Monilistylus) monilistylus by presence of brown maculae on the wings, coloration of abdomen and the shape of the first segment of the gonostylus. Larva of P. (M.) ornatipennis sp. n. differs from P. (M.) monilistylus by the following characters: dorsal surface of labrum in P. (M.) ornatipennis with long, evenly scattered setae ( Fig. 16 ), while P. (M.) monilistylus has only few very thin setae; denticles on claw in P. (M.) ornatipennis are larger and occupy nearly half of claw length ( Fig. 32 ), while in P. (M.) monilistylus they are smaller and occupy less than 1/3 of claw length (Kluge et al. 2014: fig. 21).

Male imagines of the both species of Monilistylus can be distinguished from all other Baetidae by peculiar genitals [see above, Monilistylus (1)]. Larvae of the both species of Monilistylus can be distinguished by the following combination of characters: (1) cerci with spines characteristic for Procloeon /g1 (see above) ( Fig. 7 ); (2) mandibles of the « Centroptilum - type » [see above, Monilistylus (3)] ( Figs 18–25 ) (in contrast to Procloeon s.str. and Oculogaster ); (3) labrum, maxillae and labium of a usual structure, with glossae pointed ( Figs 16, 17 , 26–29 ) (in contrast to Pseudocentroptiloides and Securiops ).

Figures

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 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 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 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.