Labiobaetis tenuicrinitus Kopelke 1980, comb. n.
Creators: name: Kluge, Nikita J.
name: Novikova, Eugenia A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Labiobaetis
Labiobaetis tenuicrinitus

description: Labiobaetis tenuicrinitus (Kopelke1980) comb. n.   
(Figs 113–141)  
 Pseudocloeon tenuicrinitum Kopelke 1980a: 117 (♂ imago); Kopelke 1980b: 304 (egg); Kopelke 1981: 16 (ecology); Lugo- Ortiz, McCafferty & Waltz 1999: 24.   
 Baetis tenuicri [ni] tus: Gillies 1994: 117;   
 Baetis spatulatus Gillies 1994: 108 (♂ imago, larva) syn. n.; Gillies 1997: 114, Fig. 2 D (tergalius); Gillies 1999: 53.   
 Material examined. UGANDA: Kasese District, Kiburara, river Nyamagasan, 8–13.VIII.2007, coll. N. Kluge: 5 L-S-IƋ, 12 L-S-I ♀, 2 L-SƋ, 33 larvae.   
  Descriptions. Larva.  CUTICULAR COLORATION. Dorsal side of head, thorax and abdomen ocher-brown, with lighter median stripe along all abdominal terga (Figs 116, 117). Legs unicolor light ocher. Cerci unicolor ocher-brown, paracercus lighter (Fig. 115). Tergalii light ocher.   
HYPODERMAL COLORATION. On legs absent. On abdomen, if present, coincides with cuticular color pattern (Figs 113, 114).  
STRUCTURE. Frons between antennae bases flat; frontal suture blunt-angled in female and acute-angled in male (Figs 124, 125). Scapus of antenna simple, without lateral-apical projection. Labrum with pair of branched submedian setae and with pair of arched latero-anterior rows of branched setae (Fig. 122). Mandibles with convex inner margin between prostheca and mola (Fig. 4; Gillies 1994: Figs 17, 18). Maxilla stout; second segment of maxillary palp thick, with shallow incision in distal part of median margin (Fig. 123). Hypopharynx without long apical spines (Fig. 137). Labium (Figs 126, 127): glossa with setae of medio-ventral row stout, subapical median seta much longer; paraglossae wide, with apical setae forming 3 rows; 2nd segment of labial palp with median projection wide and rounded.  
Vestiges of hind protoptera present (Fig. 128). Legs stout, with short spine-like setae (Fig. 133). Outer side of femur with irregular row of short stout blunt setae; in proximal part of femur these setae often form more than one row; two most distal setae often attached close one to another. Apical margin of femur with minute stout blunt setae (Fig. 135). Inner side of femur with sparse minute stout blunt setae. No structures resembling femoral patch of Baetofemorata. Tibia flattened and widened; outer margin of tibia with irregular row of minute stout blunt setae; apex of tibia bears prominent outer-apical projection with one enlarged stout blunt seta (Fig. 136); inner side of tibia with two or more irregular longitudinal rows of stout pointed setae. Outer side of tarsus with irregular minute stout blunt setae; inner side of tarsus with one regular row of stout pointed setae. Claw hooked, with 11–14 denticles (Fig. 132).  
Abdominal segments II–IX with equally small, pointed, sclerotized posterolateral spines (Figs 116, 117). Surface of abdominal terga and sterna densely covered with scales in wide semicircular sockets. Posterior margin of each tergum I–X with regular triangular pointed denticles (Fig. 138). Sterna I–V with posterior margin entirely smooth, sternum VI with few small denticles, sterna VII–IX with pointed denticles on posterior margin. Paraprocts with shorter and longer marginal denticles (Fig. 129). Tergalius I absent. Tergalii II–VII oval, with anal margin more convex than costal margin; margin entirely bordered by well-developed rib, serrate; surface without denticles and scales; tracheae colored with light brownish (Fig. 116, 117). Cerci somewhat shorter than body length, paracercus somewhat shorter than cerci (Figs 113, 115). Posterior margins of segments of cerci and paracercus with equal triangular denticles, subequal to denticles on posterior margin of abdominal terga.  
  Subimago.  CUTICULAR COLORATION. Light ocher and brownish. Pronotum light brownish. Mesonotum light brownish with medioparapsidal suture contrastingly light, other sutures slightly darkened (Fig. 119). Thoracic pleura ocher, with some sclerites light brownish, lateropostnotal crest and postsubalar sclerite without contrasting coloration (Fig. 120). Abdomen unicolor light brownish, legs and cerci lighter ocher.   
TEXTURE (see Table 2). On fore leg of male 1st–4th tarsomeres covered by blunt microlepides, 5th tarsomere covered by pointed microlepides. On fore leg of female 1st tarsomere covered mainly by microtrichia (as tibia), 2ndt–4th tarsomeres covered by blunt microlepides, 5th tarsomere covered by pointed microlepides. On middle and hind legs of male and female proximal part of 1st+2nd tarsomere (corresponding to primary 1st tarsomere) covered by microtrichia, distal part of 1st+2nd tarsomere (corresponding to primary 2nd tarsomere), 3rd and 4th tasomeres covered by blunt microlepides, 5th tarsomere covered by pointed microlepides (Fig. 134).  
 Imago, male (Fig. 121). Head ocher with brown. Turbinate eyes widened apically, with facetted surface ocher, stem light ocher. Thorax light brown with ocher areas. Wing membrane colorless, veins ocher. Pterostigma with several oblique complete and incomplete veins (Kopelke 1980a: Fig. 28). Hind wing absent. Legs unicolor ocher. Tarsus of middle and hind leg with 3 apical spines, on segments 1st+2nd, 3rd and 4th (the same in subimago—Fig. 134) (Table 2). All abdominal terga ocher-brownish with lighter longitudinal median stripe and lighter paired medioanterior and medioposterior sigilla (the same in subimago—Fig. 114). Abdominal sterna lighter than terga, ocher. Cerci unicolor ocher.   
 Male genital structure and development. Imaginal genitals as in Figs 1, 131. Sterno-styligeral muscle completely absent. Each gonovectis with apex free end straight, not hooked and not bordering distal margin of membranous sack. Penial bridge forms prominent median projection rounded apically. Apical margin of each unistyliger medially with roundish projection directed medially. Gonostylus with 1st segment smoothly narrowed toward apex, with inner margin convex; 2nd segment slightly widened toward apex; 3rd segment short.   
 Protogonostyli of male larva represent very shallow convexities of posterior margin of abdominal sternum IX. In mature larva ready to molt to subimago, subimaginal gonostyli are packed under larval cuticle in « Labiobaetis - pose»: second segments directed medially and bent (Fig. 130).   
 Imago, female (Fig. 118). Head and thorax ocher with light brownish, lighter than in male. Wings as in male. Tarsus of fore leg with 2 apical spines, on segments 2nd and 3rd (i.e., without apical spine on penultimate tarsomere); middle and hind legs as in male (i.e., with apical spine on penultimate tarsomere). All abdominal terga ocher-brownish with lighter longitudinal median stripe; terga II–VI with posterior margins diffusively darkened with brown, except light longitudinal median stripe.   
 Eggs (Figs 139–141). About 0.1 mm length. Broad-oval or nearly spherical, with fine punctuation (Kopelke 1980b: Fig. 20). One pole with round, shallowly convex cap; several long and thin processes arise from periphery of this cup; each process bears on its end spherical or ellipsoid adhesive knob (Kopelke 1980b: Figs 19, 21). Unlike coiled knob-terminated threads of eggs of some other mayflies, the knob-terminated processes of L. tenuicrinitus are always straight or arched, resilient, unable to coil up.   
 Dimension. Fore wing length of male and female about 5 mm.   
 Discussion. The description given above, is based on the specimens collected in the west of Uganda, close to the boundary with the Democratic Republic of Congo. The species under the name Pseudocloeon tenuicrinitum was described from River Kalengo, located in the neighboring region of the D. R. Congo. The original descriptions were based on male and female imagoes and eggs (Kopelke 1980a, 1980b). Characters reported in these papers allow to determine this species without doubt: eggs have unusual structure (Kopelke 1980b: Figs 19–21); genitals of male imago are described and figured in detail, including pointed gonovectes, rounded median projection, characteristic shape of medio-apical projection of unistyligers and characteristic shape of gonostyli (Kopelke 1980a: Figs 27 a, b); pointed apical spine on penultimate tarsomere is figured (Kopelke 1980a: Fig 29, 8 th position). Judging by these characters, as well as by coloration, our imagoes reared from larvae in Uganda, undoubtedly belong to this species.   
 Gillies (1994) described the species under the name Baetis spatulatus based on imagoes reared from larvae in Tanzania. He did not describe its eggs, and did not compare imagoes of spatulatus [Baetis] with tenuicrinitum [Pseudocloeon], but only noted that "The adult of B. spatulatus is poorly differentiated from several other species in which the hind wing is lost". Examination of the reared material from Uganda allows to conclude that spatulatus [Baetis] is conspecific with tenuicrinitum [Pseudocloeon].   
 Distribution. Kongo, Tanzania, Uganda.
description: Published as part of Kluge, Nikita J. & Novikova, Eugenia A., 2016, New tribe Labiobaetini tribus n., redefinition of Pseudopannota Waltz & McCafferty 1987 and descriptions of new and little known species from Zambia and Uganda, pp. 1-43 in Zootaxa 4169 (1) on pages 33-41, DOI: 10.11646/zootaxa.4169.1.1, http://zenodo.org/record/267393