Nigrobaetis kaliman, Kaltenbach & Gattolliat, 2023

Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2023, New species of Nigrobaetis from Southeast Asia (Ephemeroptera, Baetidae), ZooKeys 1166, pp. 175-234 : 175

Nigrobaetis kaliman sp. nov.

Figs 34 , 35 , 36 , 37 , 38 , 39 , 40

Differential diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submedian seta and a short, submarginal arc of three long, simple setae (Fig. 35b ); B) right mandible: incisor with four denticles, kinetodontium with four denticles (Fig. 35c ); C) left mandible: incisor with four or five denticles, kinetodontium with three denticles; margin between prostheca and mola straight, with row of few short, setae-like processes (Fig. 35d ); D) fore femur length ca. 3 × maximum width, dorsal margin with 7-9 curved, spine-like setae (Fig. 38a ); E) tibia dorsally with row of spine-like, apically rounded setae; distally with one stout, apically rounded seta (Fig. 38a, b ); F) claw with ten or eleven denticles (Fig. 38e ); G) hind protoptera absent; H) tergalii on abdominal segments I-VII; I) posterior margins of abdominal terga: I-V (IV) smooth, without spines; (V) VI-IX with triangular, pointed spines (Fig. 39a ).

Description.

Larva (Figs 34 - 39 ). Body length 3.5-4.6 mm. Caudalii broken. Antennae ca. 3 × head length.

Colouration (Fig. 34a-c ). Head, thorax, and abdomen dorsally brown, abdominal terga VI and VII darker, abdominal terga VIII and IX pale brown. Head, thorax, and abdomen ventrally pale brown. Legs brown, femur mediobasally with bright area. Caudalii brown.

Labrum (Fig. 35a, b ). Length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with medium, fine, simple setae scattered over surface; submedian seta and several long, simple, submarginal setae. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid, pectinate setae.

Right mandible (Fig. 35c ). Incisor and kinetodontium fused. Incisor with four denticles; kinetodontium with four denticles, inner margin of innermost denticle without row of thin setae. Prostheca stick-like, apicolaterally denticulate. Margin between prostheca and mola straight, with row of setae-like processes. Tuft of setae at apex of mola present.

Left mandible (Fig. 35d ). Incisor and kinetodontium fused. Incisor with four denticles; kinetodontium with three denticles. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola straight, with row of short, setae-like processes. Tuft of setae at apex of mola absent.

Hypopharynx and superlinguae (Fig. 36a ). Lingua shorter than Hypopharynx superlinguae . Lingua longer than broad; medial tuft of stout setae poorly developed; distal half laterally slightly expanded. Superlinguae distally rounded; lateral margins rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 36b-d ). Galea-lacinia ventrally with two simple, apical setae under canines. Medially with one spine-like, pectinate seta and ca. five long, simple setae. Maxillary palp ca. 1.3 × as long as length of galea-lacinia; 2-segmented; palp segment II approx. as long as segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment slightly pointed.

Labium (Fig. 37a-f ). Glossa basally broad, narrowing toward apex; approx. as long as paraglossa; inner margin with ca. seven spine-like setae; apex with two long and one medium, robust setae; outer margin with ca. six spine-like setae; ventral surface with row of fine, simple, setae along inner margin. Paraglossa curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area and ca. three medium, simple setae in distal area; dorsally with three long, spine-like, simple setae near inner margin. Labial palp with segment I slightly longer than segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II without protuberance; ventral surface with short, fine, simple setae; dorsally with row of ca. four long, spine-like setae. Segment III slightly pentagonal; length ca. 1.2 × maximum width; inner apical margin with some setae-like processes (Fig. 37f ); ventrally with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera: Absent.

Foreleg (Fig. 38a-e ). Ratio of foreleg segments 1.3:1.0:0.7:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with 7-9 curved, spine-like setae; length of setae 0.31 × maximum width of femur. Apex rounded, with pair of spine-like setae. Medium, stout, lanceolate setae along ventral margin; femoral patch absent. Tibia. Dorsal margin with row of spine-like, apically rounded setae; on apex one stout, apically rounded seta. Ventral margin with row of short, curved, spine-like setae; on apex two longer, spine-like, pectinate setae. Anterior surface with stout, lanceolate, slightly pectinate setae along ventral margin. Patellatibial suture present on basal half. Tarsus. Dorsal margin bare. Ventral margin with row of curved, spine-like, pectinate setae. Claw with one row of ten or eleven denticles; distally pointed; subapical setae absent.

Middle and hind legs. As foreleg.

Abdominal terga (Fig. 39a ). Surface with irregular rows of U-shaped scale bases. Posterior margin of terga: I-V (IV) smooth, without spines; (V) VI-IX with triangular, pointed spines.

Abdominal sterna. Posterior margin of sterna smooth, without spines.

Tergalii (Fig. 38f ). Present on segments I-VII. Margin with small denticles intercalating fine simple setae. Tracheae restricted to main trunk and few branches, not reaching margins. Tergalius I as long as length of segment II; Tergalius IV as long as length of segments V and 1/3 VI combined; Tergalius VII as long as segments VIII and IX combined.

Paraproct. With six or seven stout, marginal spines. Surface scattered with U-shaped scale bases and micropores. Cercotractor with numerous small, marginal spines.

Adult stages. Unknown.

Eggs (Fig. 40a, b ). Egg of Fig. 40a still in early stage of development, probably not showing the final shape (see Fig. 40b , pack of developing eggs extracted from same larva). Surface with numerous papillae-like structural elements (polygonal to rounded structure, centrally with a smaller, rounded, slightly elevated area surrounded by a round trench).

Etymology.

Referring to the province Kalimantan (Indonesia, Borneo), where the species was collected.

Distribution

(Fig. 40c ). Indonesia, Borneo (East Kalimantan).

Biological aspects.

The specimens were collected on altitudes of ca. 130 m. The streams were 2-30 m wide, ca. 0.1 m deep, and flowing with ca. 0.6 m/s. The location was dominated by riffles and run, substrate was mainly gravel and cobble, water temperature ca. 26 °C.

Type-material.

Holotype. Indonesia • larva; East Kalimantan, Bas. Malinau, riv. Seturan, loc. Seturan, main river; 116°30'48"E, 03°00'05"N, 28.iii.2001; leg. P. Derleth and B. Feldmeyer; on slide; GBIFCH00592661; MZL. Paratypes. Indonesia • 3 larvae; same data as holotype; 2 on slides; GBIFCH00592655, GBIFCH00592662; MZL • 2 larvae; East Kalimantan, Bas. Malinau, Riv. Seturan, Loc. Seturan (1999-bloc 39-40), Trib. Temalat (Sungai Guang); 03°00'10"N, 116°32'24"E; 27.iii.2001; leg. P. Derleth; in alcohol; GBIFCH00975671; MZL • 2 larvae; East Kalimantan, Bas. Malinau, Riv. Seturan, Loc. Seturan (2001-bloc 57), Trib. Tamalang (Sungai Guang); 18.vii.2001; leg. P. Derleth and F. Béboux; 1 on slide; GBIFCH00592614; 1 in alcohol; GBIFCH00975683; MZL • 5 larvae; East Kalimantan, Bas. Malinau, Riv. Seturan, Loc. Seturan (2001-bloc 57), Trib. Tamalang (Sungai Guang); 10.iv.2001; leg. P. Derleth; in alcohol; GBIFCH00975684, GBIFCH00975685; MZL • 2 larvae; East Kalimantan, Bas. Malinau, riv. Rian, loc. Langap South (1997-bloc 6), trib. Belakau; 116°30'26"E, 3°04'04"N; 18.iv.2001; leg. P. Derleth and M. Sartori; in alcohol; GBIFCH00975672; MZL • 1 larva; East Kalimantan, Bas. Malinau, riv. Seturan, loc. Seturan (2000-bloc 43), trib. Temalat (Sungai Guang); 116°33'29"E, 02°59'29"N; 16.viii.2000; leg. P. Derleth and R. Schlaepfer; in alcohol; GBIFCH00975673; MZL • 3 larvae; East Kalimantan, Bas. Malinau, Riv. Rian, Loc. Langap Sud (1995), Trib. Ngayo; 03°04'56"N, 116°30'58"E; 17.iv.2001; leg. P. Derleth and M. Sartori; 2 on slides; GBIFCH00592656, GBIFCH00975691; 1 in alcohol; GBIFCH00975693; MZL.

Figures

Figure 34. Nigrobaetis kaliman sp. nov., larva habitus a dorsal view b ventral view (a, b after more than 20 years in 70 % alcohol) c dorsal view (soon after collection). Scale bars: 1 mm.

Figure 35. Nigrobaetis kaliman sp. nov., larva morphology a labrum, ventral focus b labrum, dorsal focus (arrows: submedian and submarginal setae) c right mandible d left mandible. Scale bars: 20 µm.

Figure 36. Nigrobaetis kaliman sp. nov., larva morphology a hypopharynx and Hypopharynx superlinguae b, c maxilla d maxilla, ventrolateral section. Scale bars: 20 µm.

Figure 37. Nigrobaetis kaliman sp. nov., larva morphology a labium b labial palp, dorsal focus c labial palp, ventral focus d glossae and paraglossae, ventral focus e apex of glossae and paraglossae, dorsal focus f labial palp, inner apical margin of segment III (arrows: setae-like processes). Scale bars: 20 µm.

Figure 38. Nigrobaetis kaliman sp. nov., larva morphology a foreleg b setae on dorsal apex of fore tibia c setae of anterior surface of fore tibia d ventral apex of fore tibia and base of fore tarsus e fore claw f tergalius IV g section of margin of tergalius IV. Scale bars: 50 µm.

Figure 39. Nigrobaetis kaliman sp. nov., larva morphology a posterior margins of abdominal tergites VI-VII b paraproct. Scale bars: 20 µm.

Figure 40. a Nigrobaetis kaliman sp. nov., egg b Nigrobaetis kaliman sp. nov., pack of developing eggs (extracted from same larva than a) c distribution of Nigrobaetis species in Indonesia. Scale bars: 40 µm (a, b).