Branchiobaetis joachimi, Kaltenbach & Kluge & Gattolliat, 2022

Kaltenbach, Thomas, Kluge, Nikita J. & Gattolliat, Jean-Luc, 2022, A widespread new genus of Baetidae (Baetidae, Ephemeroptera) from Southeast Asia, ZooKeys 1135, pp. 1-59 : 1

5. Branchiobaetis joachimi sp. nov.

Figs 18 , 19 , 24c, d , 26c , 28b

Type material.

Holotype. Indonesia • Sumatra, volcano Marapi, East; 00°21'33"S, 100°30'42"E; 1205 m; 03.IV.2014; leg. M. Gueuning; larva on slide; GBIFCH00422405; MZL. Paratypes. Same data as holotype; 19 larvae in alcohol; GBIFCH00422228, GBIFCH00422235, GBIFCH00422238, GBIFCH00422241, GBIFCH00422254, GBIFCH00422266, GBIFCH00422402, GBIFCH00422440, GBIFCH00422489, GBIFCH00422709, GBIFCH00422844, GBIFCH00422887, GBIFCH00422932, GBIFCH00422977; MZL. Indonesia • Sumatra, volcano Sago, River Kobun; 00°22'33"S, 100°39'33"E; 1095 m; 19.III.2014; leg. M. Gueuning; 2 larvae on slide; GBIFCH00592506, GBIFCH00592507; 22 larvae in alcohol; GBIFCH00422152, GBIFCH00422166, GBIFCH00422173, GBIFCH00422222, GBIFCH00422226, GBIFCH00422227, GBIFCH00422253, GBIFCH00422256, GBIFCH00422258, GBIFCH00422266, GBIFCH00422268, GBIFCH00422270, GBIFCH00422663, GBIFCH00422708, GBIFCH00422754, GBIFCH00422928, GBIFCH00422979, GBIFCH00423113; MZL • Sumatra, volcano Sago, River Tampo; 00°22'20"S, 100°41'45"E; 960 m; 20.III.2014; leg. M. Gueuning; 8 larvae in alcohol; GBIFCH00422232, GBIFCH00422239, GBIFCH00422249, GBIFCH00422250, GBIFCH00422255, GBIFCH00422265, GBIFCH00422619, GBIFCH00423112; MZL • Sumatra, volcano Sago, River Tampo; 00°20'37"S, 100°41'02"E; 1255 m; 21.III.2014; leg. M. Gueuning; 12 larvae in alcohol; GBIFCH00422230, GBIFCH00422236, GBIFCH00422237, GBIFCH00422243, GBIFCH00422251, GBIFCH00422264, GBIFCH00422883, GBIFCH00423026, GBIFCH00423068, GBIFCH00423116; MZL • Sumatra, volcano Sago, River Kaligain; 00°18'01"S, 100°40'08"E; 1040 m; 05.IV.2014; leg. M. Gueuning; 1 larva on slide; GBIFCH00592525; 22 larvae in alcohol; GBIFCH00422229, GBIFCH00422234, GBIFCH00422244, GBIFCH00422246, GBIFCH00422259, GBIFCH00422263, GBIFCH00422304, GBIFCH00422441, GBIFCH00422442, GBIFCH00422443, GBIFCH00422659, GBIFCH00975612, GBIFCH00975613; MZL • Sumatra, volcano Singgalang, River Airjernih; 00°24'07"S, 100°16'44"E; 840 m; 25.III.2014; leg. M. Gueuning; 1 larva on slide; GBIFCH00422159; 7 larvae in alcohol; GBIFCH00422052, GBIFCH00422142, GBIFCH00422157, GBIFCH00422160, GBIFCH00422618, GBIFCH00422752, GBIFCH00423024; MZL • Sumatra, volcano Singgalang, River Magyih; 00°23'33"S, 100°16'34"E; 845 m; 25.III.2014; leg. M. Gueuning; 1 larva on slide; GBIFCH00422211; 5 larvae in alcohol; GBIFCH00422081, GBIFCH00422154, GBIFCH00422198, GBIFCH00422201, GBIFCH00422217; MZL • Sumatra, volcano Singgalang, River Magyih; 00°22'50"S, 100°17'39"E; 1075 m; 26.III.2014; leg. M. Gueuning; 3 larvae in alcohol; GBIFCH00422098, GBIFCH00422168, GBIFCH00422221; MZL • Sumatra, volcano Singgalang, River Sianok; 00°19'57"S, 100°19'19"E; 1150 m; 24.03.2014; leg. M. Gueuning; 1 larva in alcohol; GBIFCH00422248; MZL.

Other material.

Indonesia • Sumatra Barat, Bukit Barisan, above Padang , creek; 00°56'44"S, 100°32'44"E; 1047 m; 08.XI.2011; leg. M. Balke (UN3); 3 larvae on slides; GBIFCH00592472, GBIFCH00592473, GBIFCH00592505; 17 larvae in alcohol; GBIFCH00975598, GBIFCH00975599, GBIFCH00975602, GBIFCH00980897, GBIFCH00980898; MZL .

Differential diagnosis.

Larva. Following combination of characters distinguish B. joachimi sp. nov. from other species of Branchiobaetis gen. nov.: A) labial palp segment II with short, broad, rounded protuberance, with few small, stout, simple setae on protuberance; segment III apically rounded (Fig. 18k ); B) dorsal margin of femur with row of medium, spine-like setae; many short, stout, apically rounded setae along dorsal margin; same type of setae scattered on surface and along ventral margin (Fig. 19a, c ); C) posterior margin of tergites: I with triangular, pointed spines or short, triangular, blunt spines; II-IX with triangular, pointed spines, longer than wide (Fig. 19f ); posterior margin of sternites: I-IV smooth, without spines; V with small, spaced, triangular spines; VI-IX with triangular spines; D) paraproct with short, stout, apically rounded setae along posterior margin (Fig. 19h ).

Description.

Larva (Figs 18 , 19 , 24c, d , 26c ). Body length 7.9-9.6 mm. Cerci: ca. 0.6 × body length. Paracercus: ca. 0.6 × cerci length. Antenna: ca. 2.5 × as long as head length.

Colouration (Fig. 24c, d ). Head, thorax and abdomen dorsally brown or grey-brown, with pattern as in Fig. 24c or 24d; head, thorax and abdomen ventrally light brown or light grey, abdominal segment IX laterally with dark brown streaks. Femur light brown or light grey, apically and dorsally along margin dark brown, with large, distomedial, dark brown spot; tibia light brown or grey, basally dark brown along patella-tibial suture; tarsus light brown or grey, dark brown in distal half. Caudalii light grey-brown, darker brown area on ca. ½ of cerci length; primary swimming setae dark brown.

Precursors of turbinate eyes in male last instar larvae representing a pair of brownish, egg-shaped maculae; in the middle of this macula, a smaller, round, elevated area with well-expressed facets, ca. 14 facets in diameter; peripheral area of the macula with indistinct facets (Figs 24c, d , 25d ).

Antenna (Fig. 19i ). Scape distally and outside distolaterally with short, stout, apically rounded setae.

Labrum (Fig. 18a ). Length 0.6 × maximum width. Submarginal arc of setae composed of 10-12 long, simple setae.

Right mandible (Fig. 18b-d ). Incisor blade-like with three denticles; kinetodontium with four denticles. Margin between prostheca and mola straight, with minute denticles.

Left mandible (Fig. 18e, f ). Incisor blade-like with four denticles; kinetodontium with three denticles. Margin between prostheca and mola straight, with minute denticles towards subtriangular process.

Both mandibles with lateral margins almost straight.

Hypopharynx and superlinguae (Fig. 18g ). Lingua as long as superlinguae. Lingua longer than broad; medial tuft of stout setae well developed. Superlinguae distally rounded; lateral margins rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 18h, i ). Galea-lacinia ventrally with two simple, apical setae under canines. Medially with one pectinate, spine-like seta and 8-11 short to long, simple setae, not all in a row. Maxillary palp slightly longer than galea-lacinia; palp segment II ca. 1.2 × as long as segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II.

Labium (Fig. 18k ). Inner margin of glossa with ca. 14 spine-like setae, increasing in length distally; apex with two long and one medium, robust setae; outer margin with approx. nine spine-like setae; Paraglossa with three or four short, simple setae in anteromedial area and one in posterolateral area; dorsally with three long, spine-like setae near inner margin. Labial palp with segment I approx. as long as length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with short, broad, rounded, distomedial protuberance; distomedial protuberance 0.2 × width of base of segment III; ventral surface with short, fine, simple setae and some short, stout, simple setae; dorsally with 4-6 spine-like setae near outer margin. Segment III about semi-circular, apically rounded; length 0.8 × maximum width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Foreleg (Fig. 19a-e ). Ratio of foreleg segments 1.5:1.0:0.5:0.2. Femur. Slender, length ca. 4 × maximum width. Dorsal margin with row of 8-10 medium, curved, spine-like setae and basally 8-10 setae of same type, but standing denser and in more than one row. Further row of short, stout, hook-like setae on distal half of margin. Additionally many short, stout, apically rounded setae along dorsal margin. Same type of setae also on surface and many scattered along ventral margin. Apex rounded, with pair of medium, curved, spine-like setae and many short, hook-like setae. Tibia. Dorsal margin with row of short, stout, apically rounded setae. On surface same type of setae along patella-tibial suture. Ventral margin with row of short, curved, spine-like setae, on apex a tuft of fine, simple setae. Tarsus. Dorsal margin with row of short, stout setae and row of fine, simple setae. Claw with one row of ten denticles.

Terga (Fig. 19f ). Surface with irregular rows of U-shaped scale bases and scattered micropores. Posterior margin of tergites: I with triangular, pointed spines or short, triangular, blunt spines; II-IX with triangular, pointed spines, longer than wide. Posterior margin of sternites: I-IV smooth, without spines; V with small, spaced, triangular spines; VI-IX with triangular spines.

Tergalii (Figs 19g , 26c ). Tracheae extending from main trunk to inner and outer margins; with light brown band along main trunk of tracheae on anal side. Tergalius I 3/4 as long as segment II, tergalius IV as long as length of segments V and 1/2 VI combined, tergalius VII as long as length of segments VIII and ¼ IX combined.

Paraproct (Fig. 19h ). Posterior margin with 18-21 stout spines. Short, stout, apically rounded setae near posterior margin. Surface scattered with scale bases, micropores and fine, simple setae.

Etymology.

Dedicated to Joachim Kaltenbach, the late father of the first author.

Distribution.

Indonesia: Sumatra (Fig. 28b ).

Biological aspects.

The specimens were collected on altitudes between 845 m and 1270 m, in the following physical conditions: slope 5-10%, width of stream 0.2-8 m, depth 7-40 cm, velocity 0.3 m/s-0.8 m/s, pH 6.5-7.5, stream bed dominated by boulder, stones and gravel and only exceptionally by sand and silt. Some of the sites were influenced or polluted by human activities.

Figures

Figure 18. Branchiobaetis joachimi sp. nov., larva a labrum (left: ventral view, right: dorsal view) b right mandible c right prostheca d mola apex of right mandible e left mandible f left prostheca g hypopharynx and superlinguae h maxilla i apex of maxillary palp j accessory gill between stipes and cardo of maxilla k labium (left: ventral view, right: dorsal view).

Figure 19. Branchiobaetis joachimi sp. nov., larva a foreleg b hook-like seta of femur apex c seta on ventral surface of femur d fore femur apex, posterior view e fore claw f tergum IV g tergalius IV h paraproct i base of antenna.

Figure 24. Habitus, larvae, dorsal view a Branchiobaetis aduncus sp. nov. b Branchiobaetis hamatus sp. nov. c Branchiobaetis joachimi sp. nov. (Sumatra, volcano Sago) d Branchiobaetis joachimi sp. nov. (Sumatra, Bukit Barisan, above Padang).

Figure 25. Habitus, larvae, dorsal view a Branchiobaetis minangkabau sp. nov. b Branchiobaetis jhoanae sp. nov. Precursors of turbinate eyes developing in male last instar larvae c Branchiobaetis hamatus sp. nov. d Branchiobaetis joachimi sp. nov. e Branchiobaetis minangkabau sp. nov.

Figure 26. Larva, tergalii IV a Branchiobaetis aduncus sp. nov. b Branchiobaetis hamatus sp. nov. c Branchiobaetis joachimi sp. nov. d Branchiobaetis minangkabau sp. nov. e Branchiobaetis jhoanae sp. nov.

Figure 28. Distribution maps a, b new species of Branchiobaetis gen. nov. in Sumatra.