Purenleon cautus ( Walker, 1853 ) Machadoa & Tavaresb, 2020

Machado, Renato Jose Pires & Tavares, Leon Gustavo de Miranda, 2020, Notes on the Brazilian species of Purenleon Stange (Neuroptera: Myrmeleontidae), with description of two new species, Insect Systematics & Evolution 51 (1), pp. 62-80 : 64-69

Purenleon cautus ( Walker, 1853) comb. n.

Myrmeleon cautus Walker 1853:349 .

Formicaleo cautus Hagen 1866:404.

Psammoleon cautus Banks 1943:170 .

Dimarella cauta Stange 2002:286 ; Stange 2004:114; Oswald 2018.

Formicaleo bipunctatus Navás 1915:465 synonym reestablished; synonymized by Banks 1943:170; transferred to Dimarella by Stange 2002:286.

Diagnosis. Area between antennae yellow; forefemur set with few short black setae; mid tibia weakly swollen, hind wing apex hyaline; female sternite VIII without posterolateral lobes; male ectoproct with postventral lobes.

Description

Lengths: forewing: 22.7–25.9 mm; hind wing: 22.8–25.6 mm.

Head ( Figs. 2a, b ): Labrum pale yellow, with a line of elongate brown setae. Clypeus pale yellow, set with long pale setae. Frons dark brown, except for the yellow space between antennae; set with few short pale setae. Gena dark brown except by a yellow line at the eyes margin. Vertex raised; mostly brown with circular dark marks, particularly near the posterior margin; set with short black setae. Ocular rim setae absent. Antennae clavate; about three times longer than pronotum length; distance between antennae about the same size of scape width; scape and pedicel with anterior surface pale yellow and posterior surface dark brown; flagellomeres about as long as wide, except by the ones at the apex, which are wider than long; flagellomeres with basal half dark brown and apical half pale yellow, but the ones at the apex with the dark brown area reduced; all segments set with short black setae. Mandible pale yellow with apex dark. Maxillary and labial palpi pale yellow, except by the brown area around the palpimacula; apical labial palpomere fusiform, palpimacula oval-shaped, located medially.

Thorax ( Figs. 2b ): Pronotum slightly wider than long; posterior margin wider than anterior; subapical furrow present; mostly dark brown, except by a small yellow line medially at the anterior margin; set with long black setae. Mesonotum dark brown, except by some pale yellow areas around the sutures; set with short black setae but prescutum with some long black setae. Metanotum dark brown, except by a medial line pale yellow; set with few short pale setae. Pterothoracic pleura mostly pale yellow with dark brown marks on each segment; set with long white setae.

Wings ( Fig. 2c ): Narrow with apex acute. Banksian lines absent in both wings. Veins intercalating dark brown and pale areas; beset with short black setae. Forewing membrane mostly hyaline with few dark brown areas: one small curved line in the cubital area (arising at the level of the prefork area apex); two marks at the rhegmal area, and small marks surrounding few apical crossveins; cubital fork basal to Rs origin; seven presectoral crossveins; subcostal veinlets simple; posterior and prefork area about the same size. Hind wing membrane hyaline; medial fork located between origins of Rs and MA; subcostal veinlets simple; one presectoral crossvein.

Legs ( Fig. 2d ): All pairs; tibia and femur about the same size and slightly longer than tarsi, (hind leg with tibia and femur much longer than tarsi); tibial spurs long, reaching T4 apex in the fore and mid leg and T2 apex in the hind leg; tarsomeres length: T1> T2, T2 = T3 = T4, T5 = T1-T4; claws about as long as T5 half and not capable of closing. Foreleg: sense hair about as long as femur; segments set with short black setae and some long white or black setae; femur stout; tibia with a antennal cleaning setae in most of ventral surface; all segments pale yellow, except by the dark brown apex of femur, tibia and T5, and rounded dark brown marks at the base of the long setae on femur and tibia. Mid leg similar to foreleg, except for tibia slightly swollen. Hind leg similar to other legs except by sense hair absent, and less rounded dark marks.

Abdomen: Segments mostly dark brown with some pale yellow marks, particularly on sternites where the pale areas are larger. Tergites set with short black setae, and sternites set with short white setae (except sternite IX set with black setae).

Male Terminalia ( Fig. 3 ): Ectoproct rounded in lateral view, with an elongated postventral lobe; set with elongate black setae. Genitalia not studied here.

Female Terminalia ( Fig. 4 ): Ectoproct rounded, set with thin elongate setae dorsally and few digging setae on ventral area. Lateral gonapophyses about as large as ectoproct in lateral view, beset with long digging setae on apex. Tergite IX rounded on ventral margin, set with few thickened setae. Sternite VII short, with distal margin straight in ventral view; covered with short setae. Pregenital plate absent. Posterior gonapophyses digitiform, about four times longer than wide, beset with long black setae, about as long as the gonapophyses. Anterior gonapophyses absent. Ventral membrane covered with short black setae, gonapophyseal plates elongate.

Remarks. With the creation of Purenleon, Stange (2002) distributed the species previously classified in Psammoleon in Euptilon and Purenleon , except by three species that were transferred to Dimarella ( P. bipunctatus , P. cautus and P. nebulosus (Navás)) . Later, Stange (2004) synonymized P. nebulosus under Dimarella cauta , and revalidated Dimarella bipunctata , which was previously synonymized under P. cautus by Banks (1943). However, after the study of high-resolution images of the type specimens of the three species mentioned above, and the addition of the female specimen described here, it is clear that they do not belong to Dimarella , and should be transferred to Purenleon .

Stange (2002) based the transference of these species to Dimarella on their elongated male ectoproct, despite the fact that they do not present the other typical characteristics of the genus. On contrary, these three species present all generic characteristics of Purenleon , lacking all the major characters of Dimarella . In fact, Dimarella is characterized by specimens with a very typical body: they are skinny insects with elongated legs, tarsal claws are capable of closing against the pretarsus, antennae located medially in the head, and highly modified meso and metathorax (flattened with legs arising on the posterior corner of the segments). The elongated male ectoprocts mentioned by Stange (2002) are indeed present in Dimarella , but a new species from Brazil (not published yet) does not present it, suggesting this is a plastic character within the genus, and should not be used to define it.

The study of the type specimens also allowed us to reevaluate the synonyms proposed by Banks (1943) and Stange (2004). The types of Myrmeleon cautus ( Fig. 3 ) and Formicaleo bipunctatus ( Fig. 5 ) are nearly identical, presenting the same body color pattern and the same spots on the forewing. In this sense, we are hereby reestablishing the synonym proposed by Banks (1943). On the other hand, the type specimens of Myrmeleon cautus and Feinerus nebulosus Navás are clearly different. The forewing of F. nebulosus ( Fig. 6 ) presents an evident posterior Banksian line (absent in M. cautus ) and different brown spots, and the hind wing presents an apical brown line that is absent in M. cautus . In this sense, the taxonomical status of F. nebulosus is revalidated here, being transferred to Purenleon . Purenleon nebulosus comb. n. clearly presents the generic characteristics of Purenleon and can be easily distinguished from the other species of the genus, based on the wing characters mentioned above.

Material examined. Holotypes: Myrmeleon cautus : BMNH: male: Brazil ( Fig. 3 ); Formicaleo bipunctatus : MNHN: female: Guiane Franç. Pariacabo, E. LE MOULT 1907 ( Fig. 5 ); Feinerus nebulosus : MNHN: female: Peru, René Martin 1920 ( Fig. 6 ) .

Other material: BRAZIL: PARÁ: Bragança, 6.ix.1978, mata de terra firme, isca luminosa (1♀ – MPEG) ( Fig. 11 ) .

Figures

Fig. 2. Purenleon cautus (Walker): a) head, anterior view; b) thorax; dorsal view; c) wings; d) mid tibia. Scale bar = 1mm. A = Anal; Cu = Cubital; Mp = Medial posterior; Ra = Radial anterior; Rs = Radial sector; Sc = Subcosta. Scale bar = 10mm. Photos provided by Benjamin Price (BMNH).

Fig. 3. Holotype of Purenleon cautus (Walker): a) habitus dorsal; b) labels. Scale bar = 10mm. Photos provided by Benjamin Price (BMNH).

Fig. 4. Purenleon cautus (Walker) female terminalia: a) lateral view; b) ventral view. E = ectoproct; GP = gonapophyseal plate; LG = lateral gonapophyses; PG = posterior gonapophyses; S = sternite; T = tergite. Scale bar = 1mm.

Fig. 5. Holotype of Formicaleo bipunctatus Navás: a) habitus dorsal; b) labels. Photos provided by André Nel (MNHN).

Fig. 6. Lectotype of Purenleon nebulosus (Navás 1923): a) habitus dorsal; b) labels. Photos provided by André Nel (MNHN).

Fig.11. Distribution map of the species of Purenleon Stange recorded to Brazil. Map shows the records presented here and previously reported.