Redescription of the subgenus Securiops Jacobus, McCafferty & Gattolliat 2006 (Ephemeroptera, Baetidae, Procloeon Bengtsson 1915) Author Kluge, Nikita J. text Zootaxa 2023 2023-09-08 5343 3 243 272 http://dx.doi.org/10.11646/zootaxa.5343.3.2 journal article 10.11646/zootaxa.5343.3.2 1175-5326 8334181 BB852CA9-6C6E-4016-9972-AAF2C378E41F Procloeon ( Securiops ) primasia ( Kaltenbach et al . 2023 ) comb. n. ( Figs 18–24 , 106–144 ) Securiops primasia Kaltenbach , Phlai-ngam, Suttinun & Gattolliat 2023: 129 (larva). Material examined. THAILAND : Kanchanaburi province , river Taphoen near falling into river Kwai-Yai , Lad-Ya (= Lat Ya ), resort «Island Resort River Kwai», 30.I–1.II.2015 , coll. N. Kluge & L. Sheyko : 5 L-S-IJ, 1 L-SJ, 1 S-IJ, 3 L-S-I ♀ , 1 L-S ♀ ; Erawan Falls , 1–4.II.2015 , coll. N. Kluge & L. Sheyko : 2 L/S ♀ , 1 L ♀ ; Mae-Hong-Son Province , river Pai upstream of Pai , 9.II.2015 , coll. N. Kluge & L. Sheyko : 1 L-S-IJ . Additions and corrections to larval and egg descriptions Cuticular coloration . Larvae of the both sexes have two sharply different forms of cuticular coloration, in one of which abdominal terga have very contrasting dark brown median part and light lateral parts ( Fig. 106 ), while another form has abdominal terga mostly light, with small brown markings ( Fig. 115 ). Kaltenbach et al . (2023) wrongly assumed that the first form is the normal one, and the second form has ́colour not yet fully developed» ( Kaltenbach et al . 2023 : fig. 1). Actually, cuticle of the both forms is finally developed, that is testified by shed exuviae shown on the Figs 106–115 . Glossa . As well as in other species of Securiops , glossa has an arched, subapical, transverse row of setae located on its dorsal side [erroneously reported as ́ventroapically» and in ́ventral view» ( Kaltenbach et al . 2023 : fig. 4d)] and a row of long, straight setae near base on its ventral side (not reported in the original description) ( Figs 116, 118–119 ). Paraglossa . In contrast to other species, inner margins of paraglossae are sharply angulate, in apical part concave and diverging ( Figs 116 ; Kaltenbach et al . 2023 : figs 4a, e). Labial palp . Setal field located on apical-dorsal side, proximally is bordered by sparse, regular row of especially large setae in high sockets (in contrast to the African species) ( Fig. 117 ). Kaltenbach et al . (2023) described the labial palp as ́2-segmented», taking the 2nd and 3dr segments fore one; however, the border separating these segments and the muscle going from the 2nd segment to the 3rd one are retained, as in other Securiops ( Kaltenbach et al . 2023 : figs 4a–b). Tibiae . The proximal end of patella-tibial suture is bent distally and connected under acute angle with row of long thin hairs (as in other Cloeon /fg1, see above) ( Fig. 120 ). In the original description, the bent portion of patella-tibial suture is not shown on the drawing ( Kaltenbach et al . 2023 : fig. 5j). Lateral spines on abdomen . Lateral spines are located on abdominal segments VIII–IX, varying from 2 to 10 larger or smaller spines on one side (not constantly seven and five spines which are reported in the original description); previous segments normally lack lateral spines; small posterolateral spines are present on abdominal segments III– VII ( Kaltenbach et al . 2023 : fig. 6a). Abdominal terga and sterna . Scales are entirely absent; all abdominal terga with numerous small, pointed, brown protuberances; all abdominal sterna with numerous colorless protuberances; besides this, abdominal terga and sterna with ring-like sensilla and fine setae, which are located sparsely and irregularly, not forming regular rows or constant pairs ( Figs 122–123 ). Tergalii . Second lamella (see characteristics of Cloeon /fg1 above) is present on tergalii of I– VI pairs and absent on tergalii of the VII pair ( Figs 18–24 ). In the original description, the second lamella was erroneously reported on tergalius VII ( Kaltenbach et al . 2023: 136 ) because on the drawing ( Kaltenbach et al . 2023 : fig. 7b) the tergalius VII was overturned, its sharply convex costal margin was taken for the anal margin, and an occasional fold along costal margin was taken for a gap separating two lamellae. Actually, the costal margin is bordered with the costal rib and cannot be expanded into second lamella; the second lamella, characteristic for Cloeon /fg1, if present, represents an outgrowth of the anal margin, which is not bordered by a rib. Tergalii of P . ( S .) primasia have characteristic species-specific shape resembling linden leaf: with apex stretched and pointed, and with costal margin more convex than in other species ( Figs 18–24 ). Cerci . Cerci of P . ( S .) primasia have unique structure: the enlarged spines on lateral side of cercus (characteristic for Procloeon /g1) are sharply differentiated: in proximal portion of the cercus all spines are stout, conic and not longer than next cercomere; in distal portion of the cercus all spines are delicate, widened from base and greatly enlarged, being as long as 2–3 next cercomeres ( Fig. 124–125 ). Original description was based on larvae with broken cerci ( Kaltenbach et al . 2023 : fig. 1), and this important character was not reported. FIGURES 106–115. Procloeon ( Securiops ) primasia , larval exuviae. 106–108, dark individual (female); 109–115, light individual (male); 106, 115, abdominal terga and sterna; 107, 110, half of pronotum and mesonotum; 108, 111, left thoracic pleura and half of metanotum; 109, part of head; 112–114, fore, middle and hind legs. FIGURES 116–119. Procloeon ( Securiops ) primasia , exuviae of labium. 116, labium (ventral setae of glossae directed proximally); 117, 2nd and 3rd segments of labial palp; 118–119, glossae in ventral and dorsal views (ventral setae directed proximally). Abbreviations: pm1, pm2, pm3, 1st–3rd palpomeres; s.d, dorsal setae of glossae; s.v, ventral setae of glossa. FIGURES 120–125. Procloeon ( Securiops ) primasia , larval exuviae. 120, base of tibia of fore leg, with focus on dorsal side; 121, the same with focus on ventral side; 122, abdominal tergum V; 123, abdominal sternum VIII; 124, cercus and paracercus; 125, portion of cercus. FIGURES 126–136. Procloeon ( Securiops ) primasia . 126–127, male imagines; 128, female imago; 129, subimaginal exuviae of half of mesonotum; 130, subimaginal exuviae of thoracic pleura; 131–133, fore leg of female imago; 134–136, its middle leg. Abbreviations: cx2, cx3, coxae of fore, middle and hind legs; lpnc, lateropostnotal crest; mtpl, pleurite of metathorax; pls, pleural suture; psa, postsubalar sclerite. FIGURES 137–142. Procloeon ( Securiops ) primasia . 137–141, genitalia of male imagines: 137, ventral view; 138, lateral view, right gonostylus and styliger removed; 139, lateral view of penis; 140, apex of penis with focus on its dorsal margin; 141, the same penis with focus on ventral side; 142, subimaginal exuviae of genitalia. Egg. Elongate-oval; chorion with even convex relief in a form of net with cells elongated along egg axis; micropyle is very small, round ( Figs 143–144 ). Kaltenbach et al . (2023) erroneously described eggs of this species as having ́four longitudinal rows of wide, sub-rectangular structural elements» ( Kaltenbach et al . 2023: 136 , figs 7c–d). Eggs described by them, were not developed; their ́sub-rectangular structural elements» are tissues of ovarium, but not elements of the egg chorion. The same egg structure is visible on scanning electron photographs in all cases when non-developed eggs are examined (e.g., see Kopelke & Müller-Liebenau 1982 : fig. 6: egg of Baetis alpinus ). FIGURES 143–145. 143–144, eggs of Procloeon ( Securiops ) primasia . 145, male imaginal genitalia of Cheleocloeon excisum ( Barnard 1932 ) , reared from larva in Eerste river 9.II.2019 by N. Kluge and L. Sheyko [the same locality as for P . ( S .) falcatum ]. Abbreviation: mp, micropyle. Descriptions of winged stages Subimago. CUTICULAR COLORATION. Head nearly colorless, antennal flagellum brownish. Pronotum colorless. Mesonotum mostly colorless, with contrasting brown grooves bordering anterolateral scutal costa, contrasting brown prealar bridge and contrasting brown lateral sclerite of parascutellum ( Fig. 129 ). Thoracic pleura and sterna mostly colorless, with contrasting brown area of pleural suture, contrasting brown postsubalar sclerite with lateropostnotal crest and brown pleura of metathorax ( Fig. 130 ). Wing cuticle colorless, microtrichia ochre. Legs colorless. Abdominal terga and sterna colorless. Gonostyli colorless ( Fig. 142 ). Cerci colorless. TEXTURE. On legs of all pairs, all tarsal segments covered with pointed microlepides (as in Fig. 70 ). Imago, male ( Figs 126–127 ). Head brown. Turbinate eyes dark brown. Thorax brown with membranes ochre. Wings colorless, with veins ochre. Pterostigma with several complete, non-branched, oblique crossveins. Legs ochre; either all legs without maculae, or fore femur with diffusive macula on outer side near base (as in Fig. 132 ). Middle and hind legs with tarsus longer than tibia, with one apical spine on initial 3rd tarsomere (actual 2nd tarsomere) (as in Figs 135–136 ). Abdomen mostly ochre; terga with diffusive brownish markings; posterior part of tergum VII and terga VIII–IX brownish. Cerci uniformly ochre. Gonostyli ochre, long and slender ( Fig. 137 ). Penial bridge forming projection semicircular in ventral view ( Fig. 137 ), apically with projection bent dorsally under right angle ( Figs 138–141 ). Imago, female ( Fig. 128 ). Head, thorax and abdomen ochre with brown markings. Fore tarsus 5-segmented, with small apical spine on 3rd segment ( Fig. 132–133 ); middle and hind tarsi 4-segmented, with apical spine on initial 3rd segment (actual 2nd segment) ( Fig. 135–136 ). Coloration of wings, legs, and cerci as in male. Dimension. Fore wing length of male and female 4–5 mm .