Procloeon (Securiops) mutadens ( Jacobus et al. 2006 ), 2023

Kluge, Nikita J., 2023, Redescription of the subgenus Securiops Jacobus, McCafferty & Gattolliat 2006 (Ephemeroptera, Baetidae, Procloeon Bengtsson 1915), Zootaxa 5343 (3), pp. 243-272 : 262

Procloeon (Securiops) mutadens ( Jacobus et al. 2006) comb. n.

( Figs 98–105 )

Cloeon dentatum: Gillies 1988: 53 (larva; non imago, nec Kimmins 1956).

Potamocloeon dentatum: Gillies 1990a: 208 (larva, non imago, nec Kimmins 1956); Jacobus & McCafferty 2005: 474 (larva).

Securiops mutadens Jacobus, McCafferty & Gattolliat 2006: 137 (larva).

Material examined. GAMBIA, Fatoto , R. Gambia, 19.II.1993, coll. M. T. Gillies, Y 127-8: 1 L ♀ .

Additions and corrections to larval description

Maxillary palp. Length of 2nd (last) segment of maxillary palp was accepted as a key character separating species of Securiops : in S. mutadens it was said to be 0.55 of 1st segment length, in contrast to 0.85 in S. macafertiorum and S. mandradae ( Jacobus & McCafferty 2005; Jacobus et al. 2006). This proportion (0.55) corresponds to the figure in the description ( Gillies 1988: fig. 30), but in another larva from the same locality in Gambia, the 2nd segment is longer, and its ratio to the 1st segment is about 0.7 ( Fig. 101 ).

Labial palp. Gillies (1988) described the labial palp as having ́two segments», 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 (as in Fig. 40 ). Distal segment of labial palp without row of stout setae, with several stout setae near outer-distal and inner-distal corners (as in Fig. 44 ).

Abdominal terga and sterna. Lateral spines are present on abdominal segments IV–IX, varying from 2 to 8 spines on one side; their number is not as constant as reported by Gillies (1988). Posterolateral spines are present on segments II–VII.

Posterior margin of abdominal tergum I is smooth, without denticles; posterior margins of terga II–X have heavily sclerotized, brown, conic, sharply pointed, spine-like denticles separated by spaces wider than denticle width ( Fig. 103 ); on tergum IX row of denticles is interrupted medially, behind pair of submedian setae (as in Fig. 51 ); projected portion of tergum X row with few larger denticles by sides, with few smaller denticles between them (as in Figs 51–52 ).

Posterior margins of abdominal sterna I–IV are smooth, without denticles; posterior margins of sterna VI–IX have colorless, conic, sharply pointed, spine-like denticles, denser than denticles on terga ( Fig. 104 ). Paraproct with spine-like denticles larger than denticles on sterna (as in Fig. 52 ).

Abdominal terga with sparse, small protuberances; terga III–X also with few, sparsely situated, oval scales in wide semilunar non-opercula-bearing sockets ( Fig. 103 ). Sterna VI–VIII also with such scales ( Fig. 104 ). Besides this, abdominal terga and sterna with ring-like sensilla and irregularly situated fine setae.

Tergalii. Tergalii I–IV with dorsal lamella, tergalii V–VII without dorsal lamella; tergalius VII enlarged ( Gillies 1988: figs 14–19). Tergalius VII was figured with its anal margin directed up, like costal margins of other tergalii ( Gillies 1988: fig. 19); probably, the author confused the anal margin with the costal one. Actually, tergalius VII has costal margin sharply convex, and anal margin straight, that is typical for Procloeon s. l. (as in Fig. 17 ).

Caudalii. On most part of cercus, lateral side of each segment with one long spine on posterior margin; these spines are gradually changed from stout and moderately long (about as long as segment lengths) in proximal part of cercus to delicate and very long (up to 3 times exceeding segment length) in middle and distal part of cercus ( Fig. 105 ). Posterior margin of each 4th segment of cercus and paracercus, followed by bark brown ring, with several pointed spines both on dorsal and ventral sides.

Winged stages. Unknown.

Egg. Unknown.

Figures

FIGURES 98–105. Procloeon (Securiops) mutadens. 98–99, left and right mandibles; 100, labrum; 101, maxilla; 102, larval cuticle of metanotum with vestige of hind protopteron; 103, abdominal tergum V; 104, abdominal sternum V; 105, caudalii. Abbreviation: sc, scales and scale sockets.

FIGURES 40–46. Procloeon (Securiops) falcatum, labium. 40, integral labium; 41–46, parts of exuviae: 41, glossae and paraglossae, ventral view; 42, half of labium of another individual (ventral setae of glossae directed distally); 43, the same individual, with ventral setae of glossae directed proximally; 44, distal segments of labial palp; 45–46, enlarged glossae in ventral and dorsal view (ventral setae directed distally). Abbreviations: m2-3, muscle going from 2nd palpomere to base of 3rd palpomere; pm1, pm2, pm3, 1st–3rd palpomeres; s.d, dorsal setae of glossae; s.v, ventral setae of glossa.

FIGURES 47–52. Procloeon (Securiops) falcatum, larva. 47, articulation of femur and tibia of fore leg, dorsal view; 48, the same, compressed to show junction of patella-tibial suture with row of fine hairs; 49, fragment of tarsus; 50, claw; 51, abdominal tergum X and margin of tergum IX; 52, abdominal tergum X and paraprocts.

FIGURES 1–24. Right tergalii of Securiops with dorsal lamella turned out. 1–7, Procloeon (Securiops) falcatum, tergalii I–VII; 8–17, two individuals of P. (S.) macafertiorum: 8–11, tergalii I–II and V–VII; 12–16, tergalii I–V; 17, the same individual, margins of abdominal segments VII–IX with tergalius VII in natural position; 18–24, P. (S.) primasia, tergalii I–VII.