Moribaetis latipennis Kluge & Bernal Vega 2018, sp. n.

Moribaetis latipennis sp. n.

(Figs 62–101)

Moribaetis maculipennis: Waltz & McCafferty 1985: fig. 32 (non figs 26–27) [non Baetis maculipennis Flowers 1979].

Moribaetis salvini: McCafferty & Lugo-Ortiz 1998: 247, figs 34–41 (larva, non imago); Lugo-Ortiz & McCafferty 1996: 369, figs 7, 9) (larva, non imago) [non Baetis salvini Eaton 1885].

? Moribaetis macaferti: McCafferty & Lugo-Ortiz 1998: 118, figs 1–8 (imago, non larva) [non Moribaetis macaferti Waltz (in Waltz & McCafferty) 1985].

Etymology. The species name is connected with the fact that the fore wing is somewhat wider than in the related species.

Material examined. Holotype (ZIN): L-S/I ♂ {specimen [XIX](4) 2018}, PANAMA, provincia de Coclé, El Valle de Anton, stream nearest to the top of the pass to La India Dormida, 3–4.II.2018, coll. N. Kluge. Paratypes: the same locality, time and collectors: 9 larvae (ZIN); provincia de Chiriqui, La Esperanza, 7 km NNW Gualaca, quebrada Comaron (8°35'40''N, 82°20'02''W), 21.I.2018, coll. N. Kluge: 3 larvae (ZIN); provincia de Bocas del Toro, bosque protector Palo Seco, near Altos del Valle: 24–28.I.2018, N. Kluge & L. Sheyko: 2 larvae (ZIN); reserva forestal Fortuna, quebrada Honda (8°45'2.15''N, 82°14'18.68''W), 11.XI.2017, coll. J. Bernal & T. Ríos: 10 larvae (UNACHI); Alambique, río Fonseca (8°22'1.46''N, 82°4'28.65''W), 7.XII.2016, coll. T. Ríos: 1 larva (UNACHI).

Diagnosis. Larva. Described by Waltz & McCafferty (1985) as « M. salvini ».

(1) Head not elongated, frons relatively wide (Figs 68–69; Waltz & McCafferty 1985: fig. 4).

(2) Mandibles [with blade-like incisor and reduced kinetodontium – see Moribaetis (2)] retain massive left prostheca and well-distinguishable right kinetodontium. On left mandible kinetodontium is fused with incisor and is represented by 3 denticles at its base (Fig. 80); on right mandible kinetodontium is also very short in comparison with incisor, but distinctly projected, curved outward from incisor and terminated by 3 denticles (Fig. 82). Prostheca of left mandible retains usual structure, with 4 blunt denticles and 3 pointed denticles (Fig. 80); prostheca of right mandible as characterized above [see Moribaetis (3)] (Fig. 82). These features can be seen in larva just after moult; often mandibles are broken; in this case left mandible retains at least projected remnant of massive prostheca, and right mandible retains at least projected remnant of kinetodontium (Figs 77–78).

(3) Femur of fore leg widened proximally (Fig. 89); stout setae on its inner side short and truncate, occupy narrow area (Fig. 95).

(4) Dark brown submedian hypodermal stripes on abdominal tergum VI about twice wider than stripes on next terga VII and VIII; stripes on terga III–IV also widened (Fig. 62).

(5) Posterior margins of abdominal sterna I–VII smooth, without denticles; that of sterna VIII–IX with sparse pointed denticles [II–X terga with larger denticles – see Moribaetis (14)].

(6) Paraproct with denticles on inner and apical margins either subequal, or gradually enlarged toward apex of paraproct (Waltz & McCafferty 1985: fig. 41).

(7) Larval cerci and their swimming setae with lighter and darker areas (Figs 62–63).

Male imago. Described by McCafferty & Lugo-Ortiz (1998) as « M. macaferti ». Differs from M. maculipennis and M. salvini by following characters.

(1) Turbinate eyes small and narrow, separated both in imago (McCafferty & Lugo-Ortiz 1998: figs 1–2) and in subimago (Figs 96–97) (in contrast to wide and contiguous in M. maculipennis).

(2) Fore wing wider than in other species; most cross veins light yellow, lighter than adjacent brown maculae (in contrast to brown in M. salvini); brown maculae present all over wing (Fig. 100; McCafferty & Lugo-Ortiz 1998: fig. 4). Hind wing of holotype without maculae (Fig. 99).

(3) Dark brown submedian hypodermal stripes on abdominal tergum VI about twice wider than stripes on next terga VII and VIII (Fig. 97) (in contrast to M. maculipennis).

(4) Femur with small contrasting brown spot on posterior side (Fig. 96) (in contrast to wide brown band in M. salvini – Fig. 102).

Female and eggs. Unknown.

Dimensions. Fore wing length of holotype 7.2 mm; length of last instar larvae 7–11 mm.

Distribution. Mexico, Costa Rica, Panama.

Comparison. Larva of M. latipennis sp. n. can be reliably distinguished from M. maculipennis by shape of mandibular incisors, right kinetodontium and left prostheca, and by wide triangular hypodermal markings on abdominal tergum VI. It also differs from M. maculipennis by denticles on abdominal sterna and paraprocts.

Male larva of M. latipennis sp. n. differs from M. maculipennis by size of dorsal eyes, in accordance with the difference between these species in size of imaginal turbinate eyes (compare Fig. 68 with Fig. 12 of last instar larva; compare Fig. 69 with Fig. 13 of penultimate instar larva). At certain phase of development, last instar larva of M. latipennis sp. n. looks as having dorsal eyes as large as in M. maculipennis (compare Fig. 62 with Fig. 1); this happens when tissues of dorsal eyes are detached from cuticle and grow under larval cuticle before transformation to subimago (Fig. 63).

Male imago of M. latipennis sp. n. differs from M. maculipennis by smaller turbinate eyes, by wider fore wings and by wide triangular hypodermal markings on abdominal tergum VI.

Male imago of M. latipennis sp. n. differs from M. salvini by light yellow cross veins bordered by brown maculae all over the wing.

Recently, larvae similar to M. latipennis sp. n., were described from Costa Rica as Moribaetis brachiostrinus Romero & Esquivel 2018. Judging by the original description, larva of M. brachiostrinus differs from M. latipennis sp. n. and M. maculipennis by shortened antennae and presence of a triangular projection on paraproct (Romero & Esquivel 2018). Both in M. latipennis sp. n. and M. brachiostrinus tergalii vary from colorless (Romero & Esquivel 2018: fig. 2) to more or less purple (Fig. 62; Romero & Esquivel 2018: fig. 3).

Comments. Both larva and imago of M. latipennis sp. n. were already described, but wrongly attributed to other species.

Larvae of M. latipennis sp. n. were ascribed to Moribaetis salvini by Waltz & McCafferty (1985). The species, originally described as Baetis salvini Eaton 1885, is known as male imago (see below). Arguments to associate larvae with this species, were formulated as the following: «Larvae that appear to match the adult color pattern of M. salvini and that fit the classification scheme concordant with the relationship of M. salvini to that of M. maculipennis are described as M. salvini...» (Waltz & McCafferty 1985: 247). Then follows the description of the larva of « M. salvini », where the color pattern is characterized as «medial areas of terga with broken pigmented pattern similar to M. maculipennis ». It is unclear, which features of coloration allowed these authors to associate these larvae with M. salvini, but not with another species of Moribaetis.

Probably, the male imago, which was ascribed to Moribaetis macaferti by McCafferty & Lugo-Ortiz (1998), belongs to M. latipennis sp. n. The single imaginal specimen examined by them, agrees with M. latipennis by having narrow turbinate eyes and widened fore wings with characteristic maculation. It differs from other specimens of M. latipennis sp. n. only by absence of dark brown submedian stripes on abdominal terga, that can be a result of fixation. Association of this single male imago with larvae of M. macaferti was based only on the fact that they were collected in the same place in Mexico. In the Discussion, it is written that «subimago from Panama that was indeed reared from larvae of M. macaferti (R.W. Flowers, pers. comm.)» (McCafferty & Lugo-Ortiz 1998: 119). Lugo Ortiz kindly examined specimens deposited in Purdue University; in the tube with male subimago and larval exuviae, besides the typed labels « PANAMA: Bocas del Toro Prov., trib. of Rio Guabo at pipeline rd. 1700' lt 28-V-1985 R.W.Flowers» and « Moribaetis macaferti Waltz det. R.W.Flowers 1988» he found a pencil-written original label, where is written «ASSOC ? Bocas Queb ʘ 1700 28-V-85 » with the question mark. Probably, association of these male subimago and larval exuviae were not reliable, as well as the conclusion about their belonging to the same species as the male imago from Mexico.