Bungona (Centroptella) papilionodes Gattolliat & Marle

Marle, Pierre, Salles, Frederico F. & Gattolliat, Jean-Luc, 2016, Two new species of Bungona Harker, 1957 (Ephemeroptera: Baetidae) from Borneo, Indonesia, Zootaxa 4088 (2), pp. 221-235 : 222-227

Bungona (Centroptella) papilionodes Gattolliat & Marle n.sp.

Figures 1–18

Material examined. Holotype: B0433D ( GBIFCH00235745 ): 1 ♂ larva; Indonesia; East Kalimantan; Langap Sud (1995); Bas. Malinau; Riv. Ngayo (Rian tributary); Long/Lat 116°30'58''E / 3°04'56''N; 160 m. a.s.l.; 14.iv.2001 ( MZL). Coll. P. Derleth. Paratypes: B1111P1 (GBIFCH00235743): 9 ♂ larvae, 5 ♀ larvae, Indonesia; East Kalimantan; Seturan (1999-bloc 27); Bas. Malinau; Riv. Seturan; Long / Lat 116°30'31''E / 3°00'57''N; 170 m. a.s.l.; 18.vii.2000 ( LIPI). B0833C (GBIFCH00235734): 1 ♂ larva; Indonesia; East Kalimantan; Seturan (2000-bloc 43); Bas. Malinau; Riv. Temalat (Sungai Guang) (Seturan tributary); Long / Lat 116°33'29''E / 2°59'29''N; 240 m. a.s.l.; 16.iv.2001 ( MZL). B1313A (GBIFCH00235748) + B1313P (GBIFCH00235718): 4 ♀ larvae, 1 ♂ larva; Indonesia; East Kalimantan; Seturan (unexploited); Bas. Malinau; Riv. Seturan; Long / Lat 116°30'48''E / 3°00'05''N; 28.iii.2001 ( MZL). B1113C (GBIFCH00235742) + B1113P (GBIFCH00235754): 4 ♂ larvae, 4 ♀ larvae; Indonesia; East Kalimantan; Seturan (1999-bloc 27); Bas. Malinau; Riv. Seturan; Long / Lat 116°30'31''E / 3°00'57''N; 140 m. a.s.l.; 26.iii.2001 ( MZL, except 1 ♂ larva, 1 ♀ larva CZNC). B0913B (GBIFCH00235740) + B0913C (GBIFCH00235752) + B0913P (GBIFCH00235730): 3 ♂ larvae, 2 ♀ larvae; Indonesia; East Kalimantan; Seturan (1998-bloc 28); Bas. Malinau; Riv. Kipah (Seturan tributary); Long / Lat 116°29'48''E / 3°01'48''N; 150 m. a.s.l.; 29.iii.2001 ( MZL). All Coll. P. Derleth.

Diagnosis. Larvae: A) Dorsal margin of femora with about seven long, clavate setae (Fig. 14); B) Maxillary palp apically pointed, subequal to galea-lacinia ( Figs. 6 a, b); C) Outer incisor on both mandibles longer than inner incisor and without additional external small denticle ( Figs. 4 a, 5); D) Segment III of labial palp subrectangular with the distal margin almost straight ( Fig. 7 ); E) Spines present on posterior margin of tergites I to X; F) Spines present on posterior margin of sternites III to IX; G) Triangular scale on surface of abdominal tergites ( Fig. 8 ).

Description. Larvae: Measurements. Length (mm). Body: 2.3–2.8; cerci: 1.0–1.1; terminal filament: 0.9–1.0; antenna: 0.5.

Colouration ( Fig. 1 ). Head uniformly yellowish. Turbinate eyes dark purple-grey. Pronotum yellowish with bowtie-like, medium brown mark; mesonotum yellowish, medium brown on posterior margin; metanotum light yellow. Legs light yellow. Abdomen: tergites IV, VII, VIII and IX light yellow; tergites I–III, V and X dark brown, sometimes with moon-shaped brown mark. Cerci light yellow.

Head. Antenna. Scape and pedicel sub-cylindrical.

Labrum ( Fig. 2 ). Subrectangular. Length about 0.5 × maximum width. Distal margin with shallow medial emargination; dorsally with one central, long, stout, simple seta and submedian arc composed of about 6 long stout setae; few short, fine setae scattered on dorsal face; distal margin with row of multifid (disto-laterally) and bifid (disto-medially) setae. Ventral surface laterally with 3 short, stout setae.

Hypopharynx ( Fig. 3 ). Lingua shorter than superlingua; distal margin rounded; covered with short, fine, simple setae. Superlingua with apex triangular; fine, simple setae scattered over distal margin.

Right mandible ( Figs. 4 a, 4b). Two slender incisor sets, partially fused; inner and outer sets with 4 + 3 denticles, respectively. Prostheca slender, bifurcated at middle ( Fig. 4 b). Margin between prostheca and mola straight with about 3 spine-like setae. Apex of mola with 2 setae.

Left mandible ( Fig. 5 ). Incisors partially fused, inner and outer sets of incisors with 4 + 3 denticles, respectively. Prostheca robust, apically with 4 denticles and 1 comb-shaped structure. Margin between prostheca and mola straight, without setae. Denticles of mola not constricted. Tuft of setae at apex of mola absent.

Maxilla ( Figs. 6 a, 6b). Apex of lacinia with row of setae with 2 denti-setae, 10 long, simple setae and 6 short spine-like setae; outer base of denticles with one simple seta. Maxillary palp 2-segmented, slightly shorter than galea-lacinia, and covered with medium, fine, simple setae; palp segment I 0.6 × length of segment II; segment II enlarged proximally and sharply pointed apically.

Labium ( Fig. 7 ). Glossae slightly longer than paraglossae; inner margin with about 14 stout setae increasing in length apically; apex with two clavate setae, and 3 stout setae; outer margin without setae. Paraglossae falciform; base with 4 short, fine, simple setae; outer margin with row of 16 long, stout setae increasing in length apically, apex with one short clavate seta, inner margin with few stout setae. Labial palp with segment I 0.7 × length of segments II and III combined; segment I covered with micropores; segment II slightly projected apically, one row of 3 stout setae ventrally, inner and outer margin bare; segment III subrectangular with distal margin straight, covered by medium simple stout setae scattered over ventral surface.

Thorax. Hindwing pads absent.

Legs ( Figs. 13 , 14, 15, 16). Femur. Length about 4.0 × maximum width; dorsally with row of about 7 long setae and 2 spine-like setae at apex; length of setae about 0.4 × maximum width of femur; ventrally with short, clavate, stout setae roughly arranged in one row, one clavate seta at apex ( Fig. 15 , but not illustrated on Fig. 14). Tibia. Dorsally with only tiny setae; ventrally with one row of short, stout setae and two feathered setae at apex. Tarsus. Dorsally with only tiny setae; ventrally with one row of feathered setae almost absent in distal half. Tarsal claw without denticles ( Figs. 13 , 16 ), apically with 3 furrows ( Fig. 13 ); subapical setae present but only visible by SEM ( Fig. 16 ).

Abdomen. Tergites. Surfaces with triangular scales and scale bases ( Figs. 8 , 18 ); posterior margins of segments I–X with spines present ( Figs. 8 , 17 ).

Sternites ( Fig. 9 ). Row of insertions of setae present on sternites IV to VI; insertions also present on sternites II and III, or III only, but generally not arranged in rows; long setae only visible by SEM. Spines present on posterior margins of segments III–X. Few triangular scales and scale bases scattered over surface.

Gills ( Fig. 10 ). Present on segments I–VII, slightly asymmetrical, posterior margins smooth but anterior margins slightly serrate. Tracheation well-marked but poorly branched. Gill I about 1/3 length of Gill IV.

Paraproct ( Fig. 11 ). With 15 marginal spines. Surface with triangular scales and scale bases. Postero-lateral extension with small marginal triangular spines; surface with scales and scale bases.

Caudal filaments. Distal margin of each segment with scales ( Fig. 12 ); inner margin with 4 setae and outer margin with 6 long, simple setae.

Imagos: Unknown.

Etymology. “ Papilionodes ” means “looking like a butterfly”; it refers to the pronotum pattern.

Discussion. Bungona (Centroptella) papilionodes presents all the characteristics of Bungona : sternites IV to VI with a row of long, tubular setae; arcs of long, tubular setae on femora, tibiae and tarsi (Figs. 14, 15); dorsal margins of femora with scarce spatulate setae (Fig. 14); spine-like setae between prostheca and mola of right mandible ( Fig. 4 b); right prostheca bifid ( Fig. 4 a) ( Salles et al. 2016). The absence of denticles on tarsal claws ( Fig. 13 ), the labrum with a subdmedian arc composed of about 6 long stout setae ( Fig. 2 ) and the relatively uniform colouration of the body ( Fig. 1 ) indicate that the species belongs to the subgenus Centroptella rather than Chopralla or Bungona s.s. ( Salles et al. 2016).

Besides the new species described herein, the subgenus Centroptella encompasses two other species: B. (C.) soldani and B. (C.) longisetosa ( Salles et al. 2016) . The main characters used to distinguish these three species are the length of maxillary palp, being short in B. (C.) longisetosa (less than one third of maxilla length); and the presence of an additional small denticle on the outer margin of the outer incisor in Centroptella species except in B. (C.) papilionodes . Additional features that also can be used include the third segment of the labial palp, which is broader in B. (C.) soldani (apical width of segment III is 1.6 × base) than in B. (C.) longisetosa and B. (C.) papilionodes ; B. (C.) papilionodes has small triangular spines on the margin of the lateral extension of the paraproct, whereas these spines are not present in the two other species; the left prostheca has four denticles in B. (C.) longisetosa but three denticles in B. (C.) soldani and B. (C.) papilionodes ( Braasch & Soldán 1980; Müller- Liebenau 1983).

Using the identification key from Soldán et al. (1987), B. (C.) papilionodes will match couplet 11; the species can be separated from C. soldani by the characters listed above. Notice also that B. (C.) similes is wrongly located in couplet 12, as it implies tarsal claws without denticles, whereas they are present, as indicated by the original description ( Müller-Liebenau 1983).

Figures

FIGURE 1. Male larvae of Bungona (Centroptella) papilionodes n. sp., dorsal view.

FIGURES 2 – 7. Larval structures of Bungona (Centroptella) papilionodes n. sp. (2) Labrum (left: ventral view; right: dorsal view). (3) Hypopharynx. (4 a) Right mandible. (4 b) Right prostheca. (5) Left mandible. (6 a) Right maxilla. (6 b) Right maxillary palp. (7) Labium (left: ventral view; right: dorsal view).

FIGURES 8 – 13. Larval structures of Bungona (Centroptella) papilionodes n. sp. (8) Distal margin of abdominal tergite IV. (9) Distal margin of abdominal sternite IV. (10) Gill IV. (11) Paraproct. (12) Segment of cercus. (13) Tarsal claw (arrows indicate furrows). (14) Foreleg.

FIGURES 15 – 18. Larval structures of Bungona (Centroptella) papilionodes n. sp., Scanning Electron Micrographs. (15) Apex of forefemur. (16) Apex of fore tarsal claw. (17) Tergites VII – X. (18) Surface of tergite IV.