Platambus convexus Okada 2011
Creators: name: Okada, Ryohei
name: Alarie, Yves
name: Michat, Mariano C.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dytiscidae
Platambus
Platambus convexus

description: Description of the larvae of Platambus convexus Okada, 2011
Source of material. 4instar I,6instar III, Japan:Nishinopporo-sawa,Nopporo,Ebetsu-shi, Hokkaido Pref., 22.III.2014, 21.III.2015, R. Okada leg; 26.XII.2015, D. Sumikawa leg; Japan: Ishihoko riv., Hatori, Ten-ei-mura, Fukushima Pref., 26.X.2016, K. Hirasawa leg. First instar larvae were reared ex ovo from adults collected at that locality. The identification of instar III is firm as P. convexus is the only Platambus species found at those localities (Okada 2011).
Diagnosis. First instar larva of P. convexus can be distinguished from the other species studied by the following combinations of features: frontoclypeus with more than 15 spatulate setae (Fig. 15); seta FR3 shorter than seta FR2 (Fig. 15); seta PA6 subequal in length to seta PA7 (Fig. 15); primary seta LA10 inserted subapically (Fig. 22); ratio L3/HW = 3.30–3.50. In addition to color patterns of head capsule (Fig. 58), last abdominal segment, and urogomphi (Figs 70, 73–82), the total number of spatulate setae on frontoclypeus, secondary setae on pro- and mesofemur, and the presence/absence of ventral setae on protarsus (Table 2) are helpful at discriminating later instars.
Instar I (Figs 15–28). Color (alcohol preserved). Dorsal surface of head capsule predominantly creamy white; frontoclypeus creamy white apically, dark brown around each egg burster; parietale creamy white with a dark brown V-shaped macula across the ecdysial suture along with some pale brown maculae. Head appendages creamy white; thoracic and abdominal terga I to VII creamy white; LAS dark brown over anterior 1/2, paler posteriorly; urogomphi creamy white; legs creamy white.
Body. Measurements and ratios that characterize the body shape are shown in Table 3.
Head. Head capsule (Figs 15–16). Subovate, sides subparallel; frontoclypeus with 15–16 spatulate setae. Antenna (Figs 17–18). A3’ protruding, finger-like.
Chaetotaxy. Seta FR3 shorter than seta FR2; seta PA6 shorter than seta PA7; seta PA13 subequal or longer than seta PA12; prementum with two additional setae on dorsal surface; setae TI2, TI3, TI6, TI7, TA6, and TA7 acute apically; seta AB2 subequal to seta AB9; seta AB15 longer than seta AB11; setae UR2, UR3 and UR4 inserted contiguously; position and number of additional setae on legs are shown in Table 1.
Instar II. No specimen was available for study.
Instar III (Figs 58, 63–64, 70, 82). As first-instar larva except as follows:
Color. Dorsal surface of head capsule yellowish; parietale yellowish with W-shaped pale brown marking and pale spot maculae across distal margin of ecdysial suture; thoracic and abdominal segments pale brown with several pale yellowish maculae; LAS brown over anterior 1/2, yellowish posteriorly.
Body. Measurements and ratios that characterize the body shape are shown in Table 3.
Head. Head capsule (Fig. 58). Frontoclypeus with 42–45 spatulate setae. Antenna. A3’ bulge-like.
Chaetotaxy. Position and number of secondary setae on legs are shown in Table 2; parietale with 6–7 spine-like secondary setae along lateral margin.
Habitat. Larvae were collected along the quiet margin of a shallow creek flowing under broadleaved trees (Fig. 86). Whereas frozen in winter, we were able to collect some larvae under ice.
description: Published as part of Okada, Ryohei, Alarie, Yves & Michat, Mariano C., 2019, Description of the larvae of four Japanese Platambus Thomson, 1859 (Coleoptera: Dytiscidae: Agabinae) with phylogenetic considerations, pp. 401-433 in Zootaxa 4646 (3) on pages 413-414, DOI: 10.11646/zootaxa.4646.3.1, http://zenodo.org/record/3351180