Arcobaetis, Kaltenbach & Kluge & Gattolliat, 2023
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publication ID |
https://dx.doi.org/10.3897/zookeys.1168.104844 |
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publication LSID |
lsid:zoobank.org:pub:28A21391-A433-4E80-8845-E5C0996EFAF0 |
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persistent identifier |
https://treatment.plazi.org/id/F4E4945E-62ED-4E71-80A0-B993DA84EB57 |
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taxon LSID |
lsid:zoobank.org:act:F4E4945E-62ED-4E71-80A0-B993DA84EB57 |
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treatment provided by |
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scientific name |
Arcobaetis |
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gen. nov. |
Arcobaetis gen. nov.
Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11 , 12 View Figure 12 , 13 View Figure 13 , 14 View Figure 14 , 15 View Figure 15 , 16 View Figure 16 , 17 View Figure 17 , 18 View Figure 18 , 19 View Figure 19
Type species.
Arcobaetis sripadai sp. nov., by present designation.
Species included in Arcobaetis gen. nov.
1. Arcobaetis sumbawensis sp. nov.
2. Arcobaetis sumatrensis sp. nov.
3. Arcobaetis bornensis sp. nov.
4. Arcobaetis sripadai sp. nov.
5. Arcobaetis gracilentus (Chang & Yang, in Kang et al. 1994), comb. nov.
Diagnosis.
Larva. The following combination of characters differentiate Arcobaetis gen. nov. from all other genera of Baetidae : A) frons with carina-like elevation, slightly overlapping antennal base (Fig. 4e View Figure 4 ); B) maxillary palp with two segments (Fig. 2g View Figure 2 ); C) both mandibles with outermost denticle in ventral position, set apart from other denticles; both mandibles with long, slightly feathered setae between prostheca and mola (Fig. 7b, d View Figure 7 ); D) paraglossae dorsally with an arc of long, spine-like, simple setae in distal area (Fig. 2h, j View Figure 2 ); E) labial palp segment II with poorly developed distomedial protuberance (Fig. 2h View Figure 2 ); F) legs very slender; femur length 4-6 × maximum width; outer margin of femora with row of short, spine-like setae (Fig. 4a-c View Figure 4 ); G) claw with single row of denticles, distal denticles larger and directed distad, proximal denticles minute (Figs 3b View Figure 3 , 5a, b View Figure 5 ); H) surface of abdominal terga with fine, longitudinally striated scales situated in angulate nests, whose angles bear opercula (Fig. 3c, d View Figure 3 ); H) folding of subimaginal gonostyli developing under cuticle of last instar male larva of the " Nigrobaetis -type".
Description.
Larva. Head (Fig. 4e View Figure 4 ). Frons with carina-like elevation, slightly overlapping antennal base.
Labrum (Fig. 2a View Figure 2 ). Sub-rectangular, wider than long. Distal margin with medial, shallow emargination and small process. Dorsally with pair of long, simple, sub-median setae, and on each side partial sub-marginal arc of long, stout, simple setae; sometimes with setae between sub-median seta and partial sub-marginal arc; surface scattered with medium to long, simple setae. Ventrally with long long-feathered setae on anterolateral margin and medium short-feathered setae on medial margin; several small, stout setae near anterolateral and sometimes also midlateral margin.
Right mandible (Fig. 2b, c View Figure 2 ). Incisor and kinetodontium fused; incisor with denticles, outer denticle turned ventrally and much lower than other denticles; kinetodontium with denticles; inner margin of innermost denticle of kinetodontium with row of thin setae; prostheca stick-like, distolaterally denticulate; margin between prostheca and mola straight, with long, slightly feathered setae; apex of mola with tuft of setae.
Left mandible (Fig. 2d, e View Figure 2 ). Incisor and kinetodontium fused; incisor with denticles, outer denticle turned ventrally and set apart from other denticles; kinetodontium with denticles; prostheca robust, distally denticulate; margin between prostheca and mola straight, with row of long, slightly feathered setae; apex of mola without tuft of setae.
Both mandibles with outer lateral margins almost straight.
Hypopharynx and superlinguae (Fig. 2f View Figure 2 ). Apex of lingua with poorly developed tuft of setae. Distolateral margin of superlinguae with fine setae.
Maxilla (Fig. 2g View Figure 2 ). Apically with three slender, pointed canines and three denti-setae; distal denti-seta tooth-like, bent in the same direction as canines; other denti-setae slender, bifid, and pectinate; maxillary palp with two segments, apex rounded.
Labium (Fig. 2h View Figure 2 ). Glossae basally broad, narrowing towards apex, shorter than paraglossae; inner margin with row of spine-like setae, increasing in length distally; apex with several medium to long, robust setae; outer margin with row of spine-like setae; ventral surface with numerous medium to long fine, simple scattered setae. Paraglossae laterally straight, distally slightly bent inwards; apex with three rows of long, robust, distally pectinate setae; ventrally usually with several short, simple setae in distomedial area; dorsally with distal arc of long, spine-like setae. Labial palp with three segments, segment II with slightly developed distomedial protuberance.
Thorax. Legs (Figs 3a, b View Figure 3 , 4a-c View Figure 4 ). Long and very slender. Femur. Length approx. 4-6 × maximum width; outer margin with row of curved, spine-like setae; apex rounded, with pair of curved, spine-like setae; ventrally with stout, pointed, pectinate setae along margin; femoral patch absent. Tibia. Outer margin of fore legs almost bare, with one curved, spine-like seta at apex; middle and hind legs additionally with row of few spine-like setae. Tarsus. Dorsal margin almost bare. Claw. Slender, with long point, and with one row of denticles. Distal denticles larger and directed distad, proximal denticles are minute.
Abdomen. Terga (Fig. 3c, d View Figure 3 ). Surface with irregular rows of scale bases and with fine, longitudinally striated scales situated in angulate nests, whose angles bear opercula (see also Kluge 2012: 365, fig. 6).
Tergalii. Present on segments I-VII or II-VII.
Paraproct (Fig. 3f View Figure 3 ). Posterior margin with stout spines. Cercotractor with numerous, small, marginal spines.
Larval protogonostyli (Fig. 4d View Figure 4 ). Subimaginal gonostyli developing under cuticle of last instar male larvae folded in " Nigrobaetis -type": all segments (1st, 2nd, and 3rd) directed caudally and compressed in longitudinal direction, base of 2nd segment deeply inserted into 1st segment, and 3rd segment inserted into 2nd segment (as in Novikova and Kluge 1994: fig. 2: 1, 5, 20).
Diagnoses.
Imago. Following combination of characters differentiate Arcobaetis gen. nov. from other genera of Baetidae A) forewing with double intercalary veins (Fig. 17a View Figure 17 ); B) gonostylus segment III extraordinary small, much narrower than apex of 2nd segment (Fig. 18a View Figure 18 ); C) gonovectes sharply bent (Fig. 18a View Figure 18 ).
Description.
Male Imago. See description of male imago under A. sripadai sp. nov. below.
Etymology.
Arcobaetis is a combination of Arco -, in reference to the Latin word arcus for arc and the arc of long, simple setae dorsodistally on paraglossae, and baetis, to highlight the similarities with the genus Baetis . The gender is masculine.
Distribution
(Fig. 19 View Figure 19 ). Indonesia (Sumatra, Sumbawa), Brunei, Sri Lanka, Taiwan.
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