Branchiobaetis javanicus (Ulmer, 1913) 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

publication ID	https://dx.doi.org/10.3897/zookeys.1135.93800
publication LSID	lsid:zoobank.org:pub:0915A6D8-A8C5-4C7A-9560-1D6EF9E14B0F
persistent identifier	https://treatment.plazi.org/id/43A16986-0A59-5469-A762-297A15ADCE3B
treatment provided by	ZooKeys by Pensoft
scientific name	Branchiobaetis javanicus (Ulmer, 1913)
status	comb. nov.

Treatment

1. Branchiobaetis javanicus (Ulmer, 1913) comb. nov.

Figs 1a, b View Figure 1 , 3a View Figure 3 , 5a-5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11d View Figure 11 , 27b View Figure 27

Baetis javanicus : Ulmer 1913: 110 (♂ & ♀ imago); Müller-Liebenau 1981: 198 (♂ imago, larva); Sartori et al. 2016: 54 (syntypes locality).

Baetis javanica : Ulmer 1924: 52 (♂ & ♀ imago); Ulmer 1939: 523 (♂ imago, ♂ subimago, ♀ subimago); ibid.: 643 (larva).

Material examined.

Type locality. Indonesia • W. Java, Gedeh, Tjibodas; 1400 m; 24.-30.XII.1930 ; leg. M. A. Lieftinck; 2 ♀ larvae on slides; ZMH • Java, Cibodas; 6-11.VIII.2009 ; leg. N. Kluge & L. Sheyko; 4 ♂ subimagos with associated larval exuviae; [III](2)B2009, [III](7)B2009; 73 larvae; slides 7.XII.2021 -1, 11.XII.2021 -1, 24.XII.2021 -1, 24.XII.2021 -2, 24.XII.2021 -3, 17.XII.2021 -1; SPbU. Other material. Indonesia • Java, vic. Bogor, Mt. Sulak , Chiapus; 06°39'29"S, 106°44'55"E; 624 m; 24.II.2008 GoogleMaps ; leg. S. Melnitsky; 1 ♂ imago; SPbU • Lombok, Mount Rinjani National Park ; 25.IX.2009 ; leg. N. Kluge & L. Sheyko; 1 ♀ imago with associated larval and subimaginal exuviae; [XXXIX](1)2009; 34 larvae; SPbU • Java, Bogor, Ciliwung River , downstream of botanical garden; 06°35'32"S, 106°48'00"E; 235 m; 01.V.2010 GoogleMaps ; leg. J.-M. Elouard; 1 larva on slide, GBIFCH00592476, 1 larva in alcohol, GBIFCH00592468; MZL • Java, Malang Batu Jalang , cascade, forest river; 07°54'52"S, 112°35'05"E; 570 m; 09.V.2010 GoogleMaps ; leg. J.-M. Elouard; 2 larvae in alcohol, GBIFCH00592466, GBIFCH00592467; MZL.

B. cf. javanicus comb. nov. material examined.

Indonesia • Sumba, forest stream; 09°38'37"S, 119°40'56"E; 470 m; 27.IX.2011; leg. M. Balke; larva on slide; GBIFCH00592481; MZL; larva in alcohol; GBFCH00592463; MZL • Sumbawa, Batu Dulang, 10 mins to Tepal, forest stream; 08°35'52"S, 117°16'41"E; 860 m; 16.IX.2011; leg. M. Balke; 2 larvae on slides; GBIFCH00592479, GBIFCH00592480; MZL; 39 larvae in alcohol; GBIFCH00592462, GBIFCH00975593, GBIFCH00975594, GBIFCH00975604, GBIFCH00975605; MZL • Bali, Ubud, Sayan, Ayung River; 08°29'59"S, 115°14'35"E; 194 m; 20.IX.2011; leg. M. Balke; larva on slide; GBIFCH00592477; MZL • Bali, Ubud, Monkey River ; 08°31'10"S, 115°15'18"E; 260 m; 16.V.2010; leg. J.-M. Elouard; larva on slide; GBIFCH00592478; MZL; 2 larvae in alcohol; GBIFCH00975611; MZL • Sumatra Barat, Universitas Andalas campus, forest stream; 00°54'40"S, 100°28'23"E; 360 m; 08.XI.2011; leg. M. Balke; 3 larvae on slides; GBIFCH00592474, GBIFCH00592475, GBIFCH00592502; MZL; 69 larvae in alcohol; GBIFCH00592489, GBIFCH00592501; GBIFCH00975582, GBIFCH00975583, GBIFCH00975595, GBIFCH00975596, GBIFCH00975597, GBIFCH00975603; MZL GoogleMaps • Flores, Maumere region , river in garden land; 08°42'55"S, 124°04'24"E; 134 m; 21.IV.2012; leg. M. Balke; 2 larvae on slides; GBIFCH00592262, GBIFCH00592297; MZL; 18 larvae in alcohol; GBIFCH00592264, GBIFCH00592265, GBIFCH00975606; MZL GoogleMaps .

Differential diagnosis.

Larva. Following combination of characters distinguish B. javanicus comb. nov. from other species of Branchiobaetis gen. nov.: A) labial palp segment II with triangular protuberance, segment III rather long ( Müller-Liebenau 1981: fig. 1b); B) dorsal margin of fore femur with row of spine-like setae, basally dense and partly arranged in double row (Fig. 7a View Figure 7 ; Müller-Liebenau 1981: fig. 1k); C) posterior margin of tergite I smooth, without spines; posterior margins of tergites II-X with triangular spines, partly longer than wide (Fig. 7j View Figure 7 ), partly as long as wide; posterior margin of sternites: I-VI smooth, without spines; VII smooth or with few small spines; VIII with few spaced, small, blunt spines; IX with triangular spines; D) paraproct not expanded, with stout setae along posterior margin.

Morphological features and their development.

Imagos and subimagos are described by Ulmer (1913, 1924). Müller-Liebenau correctly reported that hind wing has not two, but three veins (Fig. 9e View Figure 9 ; Müller-Liebenau 1981: fig. 2b). Larva is described by Ulmer (1939); larval characters are illustrated by Müller-Liebenau (1981: fig. 1). Here we give additional figures of larvae (Figs 1a, b View Figure 1 , 3a View Figure 3 , 5a View Figure 5 - 7k View Figure 7 ), subimagos (Fig. 8a-h View Figure 8 ), male imago (Figs 9a, b, j View Figure 9 , 10d-f View Figure 10 ) and female imago (Fig. 9c-g, k View Figure 9 ).

Turbinate eyes. Ulmer (1913, 1924) reported only colour of turbinate eyes (brown-grey), but not their shape. Turbinate eyes of male imago and subimago unusually small, cylindrical, with facetted surfaces round; facetted surface with approx. ten facets in diameter (Fig. 9b View Figure 9 ). In last instar male larva, precursors of the turbinate eyes representing a pair of reddish-brown maculae of egg-like shape; at middle of this macula, a smaller round area with well-expressed facets, approx. ten facets in diameter; peripheral area of the macula consists of very small and indistinct facets (Fig. 5c View Figure 5 ). Facetted surface of subimago and imago is developed from the round area, but not from the whole reddish brown macula.

Larval mandibles (Fig. 6a, b View Figure 6 ). Incisors of left and right mandibles very long and parallel-sided (i.e., blade-like), with rounded apex and two small pointed denticles in proximal half.

N.B. Such shape of mandibular incisors is only visible when they are developed inside mandibles of the previous instar (Fig. 6a, b View Figure 6 ) and possibly just after the moult, before the mandibles are hardened and the larva starts to eat. After feeding, the incisors are worn and sometimes broken, so look much shorter (see outer lines of the same figures). Such worn mandibles are figured by Müller-Liebenau (1981: fig. 1e).

Maxillary and sternal gills (Fig. 1a, b View Figure 1 ). Presence of small ventral tracheal gills not formerly reported. Presence of a pair of maxillary gills and a pair of fore coxal gills.

Each maxillary gill located on outer side of articulation between stipes and cardo; trachea penetrating into this gill, arising from paired tracheal stem which is more distally divided into branch penetrating into maxilla and branch penetrating into corresponding half of labium (Fig. 1a View Figure 1 ).

Each fore coxal gill located on inner side of coxal articulation, i.e., on the membrane between coxa and prosternum; trachea penetrating into this gill, arising from trachea going into foreleg; close to its base, trachea is divided into branch passing inside prosternum and branch penetrating into gill. Inside fore coxal gill, trachea widened, thin-walled and colourless (Fig. 1b View Figure 1 ).

Patella-tibial suture. Patella-tibial suture present on all legs of larva, female subimago and female imago, including their fore legs (that is characteristic for Anteropatellata); greatly stretched along tibia: in larva reaching inner side of tibia in distal ¼ (Fig. 7a, c View Figure 7 ), in subimago and imago near middle of tibia (Figs 8a, e View Figure 8 , 9g View Figure 9 ); in all stages patella-tibial suture barely reaching inner side of tibia, not crossing it.

Femoral patch. Each larval leg with a femoral patch/field of minute curved setae on inner side of femur near its base (that is characteristic of Baetofemorata); femoral patch on hind leg large (Fig. 7f, i View Figure 7 ), but on fore and middle legs either much smaller (Fig. 7d, e View Figure 7 ), or indistinct (Fig. 7g, h View Figure 7 ).

Texture of subimaginal tarsi (Fig. 8c, d, h View Figure 8 ). In subimagos of both sexes, all tarsomeres covered with blunt microlepides; only very basal part of first tarsomere covered with microtrichia (like tibia), and apical parts of tarsomeres with pointed microlepides.

Colouration of subimaginal cuticle. Head colourless, antennae brown. Pronotum brown. Mesonotum mostly brown (Fig. 8g View Figure 8 ). Thoracic pleura with brown and colourless areas (Fig. 8f View Figure 8 ). Legs mostly light brownish with dark brown markings on femur, tibia, and tarsus (Fig. 8a-e View Figure 8 ). Abdominal terga nearly uniformly brown, slightly darker laterally; sterna lighter; cerci lighter brownish.

Colouration of abdomen of winged males. Abdominal colouration of male imago is adequately described by Ulmer (1913, 1924). It consists of contrasting colourless-white areas, vine-red areas and black areas, with sharply different colour patterns of the terga I-II, III-IV, V-VII, VIII-IX, and X, and sharply different colour patterns of the sterna I-IV, V-VII, VIII, and IX (Fig. 9j View Figure 9 ).

Abdominal colouration of subimago was briefly characterized by Ulmer (1924) as ‘Ähnlich der Imago, Segment III bis VII bräunlichgelb durchscheinend’. Among examined male subimagos reared from larvae or extracted from mature larvae, some individuals agree with this characteristic, i.e., their terga I-II and VIII-IX are dark brown, but terga III-VII and all sterna are uniformly light brownish (Fig. 9h View Figure 9 ); some individuals have terga and sterna III-VII differentiated somewhat approximating to that of imago (Fig. 9i View Figure 9 ).

Gonostyli of male. Imaginal gonostyli with characteristic species-specific shape (Fig. 10d, e View Figure 10 ; Ulmer 1924: fig. 25): unistyliger (wrongly called 'Glied I’ in Ulmer 1924) cylindrical, somewhat narrowed at middle; segment I of gonostylus (wrongly called 'Glied II’ in Ulmer 1924) with projected blunt angle proximad of its middle; segment III of gonostylus (wrongly called 'Glied IV’ in Ulmer 1924) short and triangular, i.e., apically widened and truncate.

N.B. When developing subimaginal gonostyli are bent under the larval cuticle, segment II of gonostylus is bent medially (as in other Baetofemorata), and segment III is sharply bent laterally, that is a peculiar feature of Branchiobaetis gen. nov. (Fig. 10a, b View Figure 10 ). In subimago freed from the larval cuticle, gonostyli retain features of their previous pose under larval cuticle, with segments II sharply bent medially and segments III somewhat bent laterally (Fig. 10c View Figure 10 ); the species-specific shape of segment III is present in imaginal stage only (Fig. 10d, e View Figure 10 ). A paradoxical feature is that segment III starts to develop as unusually long (Fig. 10a View Figure 10 ), later it is bent and pressed to the 2nd segment (Fig. 10b View Figure 10 ), while subsequently it becomes shorter (Fig. 10c, d View Figure 10 ).

Internal parts of male genitalia. Sterno-styligeral muscle developed, but slender; gonovectes S-shaped, i.e., arched, with apices curved cranially (Fig. 10f View Figure 10 ).

Egg (Fig. 11a-d View Figure 11 ). Eggs irregularly oval, with irregularly situated shallow cavities, and surface of chorion rugose.

Dimension . Size rather variable: fore wing length of male and female (and the general body length) varies from 6 mm to 10 mm; females usually larger than males.

Larval habitat.

Tergalii unable for rhythmical respiratory movements (as in other Baetungulata), and larvae are unable to live for a long time in stagnant water. Larvae are most abundant in fast streams with cold water.

Distribution

(Fig. 27b View Figure 27 ). Indonesia: Java, Lombok; B. cf. javanicus comb. nov. Indonesia: Sumatra, Bali, Sumba, Sumbawa, Flores.