Camelobaetidius billi Thomas and Dominique, 2001

Boldrini, R., Salles, F. F. & Pes, A. M. O., 2012, Review of the genus Camelobaetidius Demoulin (Ephemeroptera: Baetidae) with reduced terminal filament, Journal of Natural History 46 (33 - 34), pp. 2033-2073 : 2035-2047

Camelobaetidius billi Thomas and Dominique, 2001

( Figures 1–4 ; 5A ; 6A,F,G ; 7A)

Dominique et al. 2001: 40; Dominique et al. 2002: 39; Dominique and Thomas 2002: 27; Nieto 2003: 237; Thomas et al. 2003: 123; Salles et al. 2004: 15; Salles and Dias 2004: 269; Salles, Serrão and Pereira 2005: 74; Salles and Serrão 2005: 267; Domínguez et al. 2006: 128; Boldrini and Salles 2009: 10; Nieto 2010: 7; Nieto et al. 2011: 4.

Camelobaetidius apis Nieto 2003: 237 . nov syn.

Camelobaetidius sp. 2 ; Lima et al. 2010: 730.

Diagnosis

Camelobaetidius billi differs from the other described species of the genus with the terminal filament reduced based on the following combination of characteristics.

Nymphs. (1) Segment II of labial palp with distomedial projection slightly produced ( Figure 1F ); (2) small thoracic gill present at the base of forecoxa ( Figure 6F,G ); (3) tarsal claws with 30–44 denticles; (4) paraprocts with 9–14 truncated or rounded marginal spines ( Figure 2D ).

Imagos. Male: (1) Turbinate portion of compound eyes orange; (2) anteronotal protuberance acute ( Figure 4A ); (3) forceps segment I 0.3 × length of segment II; (4) forceps segment III elongate ( Figure 4E ), 3.3 × as long as wide; (5) anterior margin of segments III and IV with reddish brown marks ( Figure 4B ). Female: (1) anteronotal protuberance acute; (2) anterior margin of segments III and IV with reddish brown marks.

Figure 7. Distribution of the species of Camelobaetidius with terminal filament reduced: (A) C. billi ; (B) -, C. francischettii , ·, C. ipaye ; (C) · – C. leentvaari , - – C. mantis . D, - – C. maranhensis , • – C. rufiventris ).

Redescription – nymph

Length of body: 3.6–4.8 mm; antennae: 1.1–2.6 mm; cerci: 3.5–6.8 mm; terminal filament: 0.4–0.6 mm; tibia I: 1.0 mm.

Head ( Figure 6A ). Brown, vertex with irregular light brown marks. Turbinate portion of male compound eyes reddish brown. Antennae with scape and pedicel subcylindrical, with short, fine, simple setae on apex of each segment. Lateral branch of epicranial suture sinuous. Labrum ( Figure 1A ). Rectangular, broader than long; dorsal surface flat. Length about 0.5 × maximum width; distal margin with shallow medial emargination and with asymmetrical margins; lateral margin with long, fine, simple setae; anterolateral margin with long, fine, pectinate setae; medially with short, robust, pectinate setae. Dorsally with short, fine, simple setae scattered over basal area; dorsolateral arc of setae with a row of 1+ 10–16 long, fine, apically pointed setae. Ventrally with short, spine-like setae on lateral and anterolateral margin. Left mandible ( Figure 1B ). Inner and outer incisors fused, respectively with 3 + 2 denticles; prostheca robust, apically denticulate; margin between prostheca and mola straight, with a row of spine-like setae; subtriangular process narrow; tuft of setae at apex of mola absent; basal half with short, fine, simple setae scattered over dorsal area. Right mandible ( Figure 1C ). Inner and outer incisors fused, respectively with 4 + 2 denticles; prostheca slender, apically denticulate; margin between prostheca and mola convex, with a row of spine-like setae; tuft of spine-like setae at base of mola present; tuft of setae at apex of mola present; basal half with short, fine, simple setae scattered over dorsal area. Hypopharynx ( Figure 1D ). Lingua shorter than superlingua; apex rounded, with tuft of short, fine, simple setae. Superlingua not expanded, with fine, simple setae scattered over lateral and distal margin. Maxilla ( Figure 1E ). Crown of galea-lacinia with inner dorsal row of setae with three pectinate denti-setae. Medial protuberance of galea with 1 + 3 long, fine, simple setae. Maxillary palp subequal in length of galea-lacinia. Palp segment II subequal in length of segment I; maxillary palp with fine, simple setae scattered over surface. Labium ( Figure 1F ). Glossa narrow and shorter than paraglossa; inner margin with seven spine-like setae increasing in length distally; apex with two long, spine-like setae; outer margin with three long spine-like setae; ventral surface with one short, fine, simple seta present or absent on anteromedian area; dorsal surface with two short, fine, simple setae near apex. Paraglossa 1.2 × length of glossa, sub-rectangular, curved inward; apex with two rows of long, fine, pectinate setae ( Figure 1 Fa); ventral surface with one fine, simple seta present or absent near base; dorsal surface with two robust, simple setae near apex. Labial palp with segment I 0.9 × length of segments II and III combined; segment I scattered with micropores, inner and outer margins with short, simple setae; segment II with distomedial protuberance slightly produced, with long, simple setae; dorsally with a row of five fine, spine-like setae; segment III rounded, length 0.5 × width, scattered with simple setae, and fine, simple spine-like setae.

Thorax ( Figure 5A ). Pronotum and mesonotum light brown with brown marks, metanotum dark brown. Hind wing pad present. Small thoracic gill present at the base of forecoxa. Foreleg ( Figure 2A ) light brown, basal half and apex of femur with brown marks. Tibia I 0.8 × length of femur, tarsi I half length of femur I. Forefemur. Length about 2.5 × maximum width; dorsally with row of c.50 long, spine-like setae; length of setae 0.2 × maximum width of femur; ventrally with short, spine-like setae scattered over surface, anterior surface with short, spine-like setae. Tibia. Dorsally with a row of short, fine, simple setae; ventrally with 11 scattered short, spine-like setae; anterior surface with long, fine, simple setae; posterior surface with short, spine-like setae near inner margin and 18 robust, spine-like setae at apex, increasing in length toward apex; tibiopatellar suture more than half length of tibia, 0.8× length of tibia. Tarsus. Dorsally with short, fine, simple setae; ventrally with seven spine-like setae, increasing in length toward apex. Tarsal claws with 30–44 denticles. Mid and hind legs similar to foreleg.

Abdomen ( Figure 5A ). Segments I–IV light brown, segments II–IV with brown marks; segments V whitish; segments VI and VII brown (usually segment II and V are whitish washed with light brown and segments VI and VII are darker). Terga IV with surface creased ( Figure 2B ); posterior margin with truncate spines. Gills ( Figure 2C ) whitish with margins light brown; margins with narrow, spine-like setae intercalating short, fine, simple setae; tracheae pigmented or not pigmented. Gills oval. Gill I subequal in length of segment II; gill IV twice length of segment V; gill VII 1.5 × length of segment VIII.

Paraproct ( Figure 2D ) with 9–14 truncated or rounded marginal spines on inner margin; surface shagreened with short, fine, simple setae; posterolateral extension smooth. Terminal filament 0.08 × length of cerci. Cerci brown; outer margin with tufts of long simple setae.

Redescription – male imago

Length of body: 4.0– 4.5 mm; antenna: 0.5 mm; forewing: 3.6–3.8 mm; hind wing: 0.7 mm; tibia I: 1.8 mm; tibia II: 0.8 mm; tibia III: 0.8 mm; cerci: 8.4 mm.

Head ( Figures 4A,B ). Brown, inner margin of compound eyes light brown. Antenna brown. Dorsal portion of compound eyes orange and oval, 1.2 × as long as wide; stalk height half width of dorsal portion; inner margins parallel.

Thorax ( Figure 4B ). Pronotum, mesonotum and metanotum brown. Medioparapsidal suture with outer margin whitish, submedioscutum with oblique whitish band. Scutellum hyaline with median whitish band. Prosternum and mesosternum brown, metasternum light brown. Anteronotal protuberance acute. Metascutellar protuberance rounded. Legs. Whitish washed with brown. Leg I: tibia 2.5 × length of femur; tarsi 1.6 × length of femur; and four segments decreasing in length apically. Leg II: tibia 1.3 × length of femur; tarsi 0.2 × length of femur. Leg III: tibia 1.4 × length of femur; tarsi 0.3 × length of femur. Forewing ( Figure 4C ) hyaline, costal and subcostal veins opaque; stigmatic area with two cross veins, not reaching Sc; marginal intercalary veins paired, except between veins ICuA2 and CuP; length of forewing about 2.7 × width. Hind wing ( Figures 4 Da,b) hyaline, with two complete longitudinal veins; costal process pointed; located on basal third.

Abdomen ( Figure 4B ). Light brown. Segments I–IV hyaline, anterior margin of segments III and IV with reddish brown marks; segments V–X whitish washed with brown, anterior margin of segment V with reddish brown mark. Sterna whitish. Cerci whitish. Genitalia ( Figure 4E ). Segments of forceps whitish, except basal segment brown. Forceps basal segment 0.3 × length of segment II; distance between segments about 0.7 × width of basal segment. Forceps segment II narrow submedially. Forceps segment III elongate, 3.3 × as long as wide; 0.2 × length of segment II. Posterior margin of subgenital plate convex.

Comments

This species was described based on nymphs from French Guiana ( Dominique et al. 2001). Later, Salles and Dias (2004) described the imagos based on reared nymphs, reporting this species for the first time from Brazil (state of Amazonas). Later, Lima et al. (2010) recorded this species from the state of Bahia as Camelobaetidius sp. 2 ; and Nieto et al. (2011) recorded this species from Venezuela. Until now, this is the species of the genus that has the widest distribution in South America. The nymphs are found more often in areas with moderate to fast currents, whereas adults are often caught by light traps.

As detailed in the description above, there was variability in the abdominal colour pattern of the nymphs ( Figure 3A–F ), number of setae of the labrum and labium, and in the shape of spines of the paraproct (which can be visualized using a microscope with phase contrast). As we found variations in specimens from the same population, we consider all as intra-specific variation.

According to Domínguez et al. (2006) nymphs of C. billi can be distinguished from C. apis by the presence or absence of spines on the paraproct, present and truncated in C. billi versus absent in C. apis . However, after examining one paratype of C. apis , we could observe the presence of truncated spines on the paraproct of this species (which are difficult to visualize). Other features that could distinguish C. apis from C. billi , at least according to the drawings presented by Nieto (2003) and Dominique et al. (2001), are the type of setae in anterolateral margin of labrum (feathered in C. billi and simple in C. apis ), and a row of abundant setae in the dorsal margin of tibiae (present in C. billi , absent in C. apis ). However, it is clear based on the examination of the type-material of C. apis , that these features were overlooked by Nieto (2003).

Thereby, C. apis is considered a junior synonym of C. billi . The description presented here was based on nymphs found in the state of Roraima ( Brazil). Camelobaetidius billi is possibly closely related to C. rufiventris and C. maranhensis , once they present the unique combination of characteristics such as the terminal filament reduced, and the absence of a projection on the inner margin of the forefemora. Camelobaetidius billi is easily differentiated from those two species, respectively, by the absence of a medial protuberance on prosternum, and by the absence of tubercles on pronotum.

Distribution

French Guiana; Argentina; Venezuela. Brazil: Amazonas, Bahia; new records: Roraima, Pará, Alagoas, Tocantins, Minas Gerais, Espírito Santo, Rio de Janeiro, Paraná, Santa Catarina, Rio Grande do Sul .

Material examined

One nymph mounted on slide and one nymph, BRAZIL, Roraima, 2 ◦ 52 ′ 19.88 ′′ N, 60 ◦ 46 ′ 52.68 ′′ W, 22 October 2004, Hamada, N. leg ( PPGBT) . One nymph mounted on slide, BRAZIL, Pará , between Itaituba and Ruropólis, 04 ◦ 10 ′ 49.7 ′′ S, 55 ◦ 14 ′ 21.8 ′′ W, 28 October 2007, Hamada, N. leg ( PPGBT) . Five nymphs mounted on slides, BRAZIL, Amazonas, Presidente Figueiredo , Igarapé Pantera , 02 ◦ 00 ′ 52 ′′ S, 60 ◦ 01 ′ 43 ′′ W, 17 October 2008, Cruz, P. V. leg (three slides in PPGBT and two slides in INPA) . Twenty-three nymphs and 10 male imagos, BRAZIL, Amazonas, Presidente Figueiredo , Igarapé Pantera , 02 ◦ 00 ′ 52 ′′ S, 60 ◦ 01 ′ 43 ′′ W, 08 November 2009, Boldrini, R. leg (13 nymphs in INPA, 10 nymphs in PPGBT and 10 imagos in INPA) . Three nymphs mounted on slides, BRAZIL, Alagoas, Murici, Cachoeira na Fazenda da Pedra Branca , 450 m, 09 ◦ 11 ′ 11.4 ′′ S, 35 ◦ 55 ′ 62.7 ′′ W, 16 March 2004, Francischetti, C.N. leg (two nymphs in PPGBT and one nymph in INPA) . One nymph, BRAZIL, Tocantins, Lajeado , 09 ◦ 45 ′ 27 ′′ S, 48 ◦ 21 ′ 23 ′′ W, 23 August 2002, Hamada, N. leg ( PPGBT) . One nymph mounted on slides, BRAZIL, Bahia, Chapada Diamantina, Palmeiras, Cachoeira do Mucujeizinho , 12 ◦ 28 ′ 28.5 ′′ S, 41 ◦ 27 ′ 16 ′′ W, 7 July 2003, Hamada, N. and Silva, J.O. leg ( PPGBT) . Eleven nymphs, same data above (three nymphs in INPA and eight nymphs in PPGBT) . Three nymphs, BRAZIL, Bahia, Camacã, Rio Panelão , 15 ◦ 24 ′ 24.9 ′′ S, 39 ◦ 32 ′ 01.8 ′′ W, 2 August 2010, Boldrini, R and Hamada, N. leg ( PPGBT) . Two nymphs, BRAZIL, Bahia, Itacaré, Cachoeira do Tremembé , 14 ◦ 09 ′ 00.6 ′′ S, 39 ◦ 05 ′ 32.8 ′′ W, 31 July 2010, Boldrini, R. and Hamada, N. leg ( PPGBT) . Four nymphs, BRAZIL, Bahia, Correntina, Rio Arrojado , 13 ◦ 26 ′ 48.5 ′′ S, 44 ◦ 33 ′ 10.3 ′′ W, 7 August 2010, Boldrini, R. and Hamada, N. leg ( PPGBT) . Three nymphs, BRAZIL, Bahia, Correntina, Rio Correntina , 13 ◦ 19 ′ 59.6 ′′ S, 44 ◦ 36 ′ 08.0 ′′ W, 7 August 2010, Boldrini, R. and Hamada, N. leg ( PPGBT) . Four nymphs, BRAZIL, Bahia, Rio de Contas, Pico do Itobira , 13 ◦ 22 ′ 55.7 ′′ S, 41 ◦ 53 ′ 39.9 ′′ W, 4 August 2010, Boldrini, R. and Hamada, N. leg ( PPGBT) . Five nymphs, Bahia, Rio de Contas, Pico do Itobirá , 13 ◦ 28 ′ 55.1 ′′ S, 41 ◦ 51 ′ 54.7 ′′ W, 4 August 2010, Boldrini, R. and Hamada, N. leg ( PPGBT) . Five nymphs, BRAZIL, Espírito Santo, Reserva Biológica Córrego do Veado , 24 February 2010, 18 ◦ 22 ′ 16.8 ′′ S, 40 ◦ 8 ′ 30.2 ′′ W, Salles, F.F. leg. ( PPGBT) . Five nymphs, BRAZIL, Espírito Santo, Sooretama, 19 ◦ 07 ′ 33.1 ′′ S, 40 ◦ 14 ′ 26.1 ′′ W, Rio São José , 19 ◦ 07 ′ 33.1 ′′ S, 40 ◦ 14 ′ 26.1 ′′ W, 06 September 2010, Salles, F.F. leg. ( PPGBT) . Four nymphs mounted on slides, BRAZIL, Espírito Santo, Caparaó , 20 ◦ 28 ′ 19.5 ′′ S, 41 ◦ 48 ′ 41.7 ′′ W, 23 April 2008, 1972 m, Boldrini, R. and Salles, F.F. leg (two slides in PPGBT and two slides in INPA) . One nymph, BRAZIL, Espírito Santo, Caparaó , 20 ◦ 28 ′ 08.8 ′′ S, 41 ◦ 43 ′ 22.5 ′′ W, 21 April 2008, 959 m, Salles, F.F. and Boldrini, R. leg ( PPGBT) . Twelve nymphs, BRAZIL, Espírito Santo, Caparaó, Cachoeira do Aurélio , 20 ◦ 28 ′ 57.5 ′′ S, 41 ◦ 50 ′ 14.5 ′′ W, 1800 m, 22 April 2008, Salles, F.F. and Boldrini, R. leg (seven nymphs in INPA and five nymphs in PPGBT) . Three nymphs mounted on slides, BRAZIL, Espírito Santo, Alfredo Chaves, Nova Mantova , Cachoeira Tadeu , 20 ◦ 39 ′ 76.6 ′′ S, 40 ◦ 50 ′ 72.6 ′′ W, 20 November 2008, Boldrini, R., leg (two slides in PPGBT and one slide in INPA) . Eight nymphs, BRAZIL, Espírito Santo, Alfredo Chaves, Nova Mantova , Cachoeira Tadeu , 20 ◦ 39 ′ 76.6 ′′ S, 40 ◦ 50 ′ 72.6 ′′ W, 14 July 2007, Boldrini, R. leg (four nymphs in PPGBT and four nymphs in INPA) . Two nymphs mounted on slides, BRAZIL, Espírito Santo, Santa Teresa, Nova Lombardia , Capitel de Santo Antônio , 19 ◦ 52 ′ 30.8 ′′ S, 40 ◦ 31 ′ 49.1 ′′ W, 20 January 2009, Boldrini, R. and Salles, F.F. leg (one slide in PPGBT and one slide in INPA21 ) . Two nymphs mounted on slides, BRAZIL, Rio de Janeiro, Itatiaia, Rio Bonito , Fazenda Aleluia , 21 June 2000, Francischettii, C.N. leg (one slide in PPGBT and one slide in INPA) . Two nymphs mounted on slides, BRAZIL, Rio de Janeiro, Itatiaia, Penedo , Rio Palmitar , 06 March 2008, De-Souza, M. R. leg ( PPGBT) . Duas ninfas, BRAZIL, Rio de Janeiro, Parque Nacional da Serra dos Órgãos , Córrego Beija Flor , 22 ◦ 26 ′ 56.0 ′′ S, 43 ◦ 00 ′ 03.4 ′′ W, 11 May 2008, Boldrini, R. leg ( INPA) . One nymph mounted on slide, BRAZIL, Minas Gerais, Catas Altas, Tabões , Parque Natural do Caraça , 20 ◦ 04 ′ 53.7 ′′ S, 43 ◦ 30 ′ 19.6 ′′ W, 1197 m, 18 May 2006, Hamada, N. leg ( PPGBT) . Two nymphs mounted on slides, BRAZIL, Santa Catarina, Seara, Camping Primavera, Rio Irani , 26 ◦ 46 ′ 1.66 ′′ S, 51 ◦ 49 ′ 49.79 ′′ W, 10 March 2009, Salles, F.F. leg (one slide on PPGBT and one slide on INPA 59 ) . Five nymphs, BRAZIL, Santa Catarina, Seara, Camping Primavera, Rio Irani , 26 ◦ 46 ′ 1.66 ′′ S, 51 ◦ 49 ′ 49.79 ′′ W, 10 March 2009, Salles, F.F. leg ( INPA) . One nymph mounted on slides, BRAZIL, Paraná, Morretes , 25 ◦ 28 ′ S, 48 ◦ 49 ′ W, 22 February 2008, Salles, F.F. leg ( PPGBT) . Two nymphs mounted on slides, BRAZIL, Rio Grande do Sul, Flona de São Francisco de Paula, Arroio Lajeado , 29 ◦ 26 ′ S, 50 ◦ 34 ′ W, 19 November 1994, Pes, A.M.O. leg (one slide on PPGBT and one slide on INPA 13 ) .

Paratype of Camelobaetidius apis . One nymph mounted on slide, ARGENTINA, Missiones, Rio Uruguai, 28 November 1980, Dominguez, E. leg ( PPGBT) .

Figures

Figure 1. Camelobaetidius billi, nymph. (A) Labrum (left v.v., right d.v.); (B) left mandible; (C) right mandible; (D) hypopharynx; (E) maxilla; (F) labium (left v.v., right d.v.); (F(a)) detail of setae of the paraglossa.

Figure 2. Camelobaetidius billi, nymph. (A) Foreleg; (B) posterior margin of terga IV; (C) gill IV; (D) paraproct.

Figure 3. Camelobaetidius billi, nymphs, body (d.v.).

Figure 4. Camelobaetidius billi, male imago. (A) Head (l.v.); (B) body (d.v.); (C) forewing; (D) hind wing (D(a) same scale of forewing; D(b) enlarged). (E) genitalia (v.v.). ANp, Anteronotal protuberance. Mps, Medioparapsidal suture. SMS, Submedioscutum.

Figure 5. Camelobaetidius spp., nymphs (d.v.). (A) C. billi; (B) C. francischettii; (C) C. ipaye; (D) C. leentvaari; (E) C. maranhensis; (F) C. rufiventris.

Figure 6. Camelobaetidius spp., nymphs. (A) C. billi (head, f.v.); (B) C. francischettii (head, f.v.); (C) C. ipaye (head, f.v.); (D) C. maranhensis (head, f.v.); (E) C. rufiventris (head, f.v.); (F) C. billi (v.v); (G) C. billi (detail of thoracic gill).