Ancyronyx punkti Freitag & Jaech , 2007

Freitag, Hendrik & Balke, Michael, 2011, Larvae and a new species of Ancyronyx Erichson, 1847 (Insecta, Coleoptera, Elmidae) from Palawan, Philippines, using DNA sequences for the assignment of the developmental stages, ZooKeys 136, pp. 47-82 : 57-60

Ancyronyx punkti Freitag & Jaech, 2007 Figs 412 A–K

Ancyronyx punkti Freitag & Jäch, 2007: 47-50 (adult description).

Material examined.

1♀ (ZMUC) "PHIL.: Palawan, P.Princesa; Bgy. Binduyan, Olanguan Falls/Brdg., Nat. Highway km 29; 2.5 km upstr.,rocks, gravel boulder, CPOM; degr. prim. veget., 10°02'11"N, 119°03'01"E 28.08.2010, leg. Freitag (126a)M"; 3 exs. (CFP) PHIL.: Palawan, P.Princesa; 2km SE Laptay/Napsan, Bubugtungan mountain stream, semi-prim.forest, 9°41'14"N, 118°27'17"E 07.9.2008, leg. Freitag (23a)M; 2 exs., 1L (0.27) (CFP) "PHIL.: Palawan, P.Princesa; Concepcion, Taranaban R.; c.6km upstr. Highw., mount.riv., riffle; boulders, woodlitter; c.150m asl 10°02'30"N, 119°00'45"E, 20.1.1995 leg. Freitag (16b)M"; 5♂♂, 6♀♀, 2 L (0.28, 0.31) (ZSM [FR002, FR008], CFP) "PHIL.: Palawan, Aborlan; Cabigaan, Talakaigan R.; mount.Riv. upst.dam, riffle, rocks, boulders,CPOM,forest, c.50m asl, 9°26'50"N, 118°26'49"E 25.2.1995, leg. Freitag (154)M"; 34 exs., 3L (0.29, 0.30, 0.31) (NMW, SMTD) "PHIL.: Palawan, Narra, 7 km N town centre, downstr. Estrella Falls, mountain riv.; sec. forest, gravel, boulders, submerged wood, riffle; c. 50m asl., c. 9°20'N, 118°23'E 16.4.2010, leg. Freitag & Pangantihon (180a)"; 1♂, 2L (0.20, 0.28) (CFP) "PHIL.: Palawan, Narra, 5 km W town proper, Taritien River near DENR Station; riffle, boulders, gravel, wood litter 9°18'55"N, 118°22'56"E 17.4.2010, leg. Freitag et al. (182b)M"; 37exs., 13L (0.24, 0.25, 0.26, 2 × 0.28, 4 × 0.30, 2 × 0.31, 2 × 0.32) (NMW, ZMUC, IMRL) "PHIL.: Palawan, Narra, 5 km W town proper, Taritien River, riffle, boulders, gravel, wood litter/leaf litter c. 100m asl. 9°19'11"N, 118°22'35"E 17.4.2010, leg. Freitag et al. (182a)"; 3 exs. (CFP) "PHIL.: Palawan, Rizal, Campung-ulay, Kalitawan Riv.; HW km 212.2, sec. veget/forest; slightly polluted, submerged wood in run, c. 30m asl. 9°19'11"N, 118°22'35"E 02.7.2010, leg. Freitag (186)"; 2L (0.29, 0.32) (CFP) "PHIL.: Palawan, Brookes P., Salogon, Manguguran Riv./Sitio, mount. riv.; rocks, CPOM, sand; riffle sec. veget., 70m asl., 8°44'07"N, 117°42'15"E 01.9.1994, leg. Freitag (148)M"; 1 L (0.31) (PCSD) "PHIL.: Palawan, Brookes P., Sabsaban River, c.10km NW of town proper, downstr. falls, grassbank rills, 8°49'N, 117°48'E 20.5.1994, leg. Freitag (79c)M".

Larval diagnosis (based on 6th instar).

Colour (Fig. 4) very similar to that of Ancyronyx minerva , but most distinctly different by ventral head portions pale; anterior yellow pronotal band not extended posteriad along the midline; meso-, metanotum and abdominal segments with rather inconspicuous or without yellow pattern at medioposterior margin and apex of abdominal segment IX with conspicuous yellow pattern extending anteriad up to c. posterior 0.3.

HW 0.32 mm; entire larva about 3.0 mm long. Body elongate, broader than that of Ancyronyx minerva , but very similar in the external characters, except for the following:

Posterolateral projections (Fig. 12A) of abdominal segments IV–VIII distinctly overreaching posterior segment margins (approximately as long as the squamose setae at posterior segment margins).

Head (Figs 4; 12 B–F) broadest posterior 0.4, not subparallel in posterior half; lateral setae moderately long; dorsolaterally with a pair of rather long double setae (Fig. 12C). Frontal suture V-shaped, rather inconspicuous (Fig. 4). Subbasal fringe of clypeus with rather short fasciculate setae. Ventral side (Fig. 12D) dominantly rugulose, without glabrous areas. Antennae as in Fig. 12E, fringe of scapus setae fasciculate with one long trichoid medial extension each, pedicel longer than in Ancyronyx minerva (c. four times as long as broad); apex of flagellum with cylindrically elongate sensillum (broken off in figured specimen). Maxilla (Figs 12D, F) with stipes slightly tapering towards apex; maxillary palpus (Fig. 12F) slightly broader and stouter than in Ancyronyx minerva . Labial mentum (Figs 12D, F) distinctly concave in posterior half, narrowest at basal 0.25, pair of trichoid setae long (reaching anterior margin) inserted sublaterally at anterior 0.2; lateroapical pair of spines broad, subtriangular, positioned at distal edge, not subapical. Submentum (prementum), ligula and labial palpi as in Ancyronyx minerva .

Pro-, meso- and metathorax (Figs 4; 12G, H) distinctly narrower anteriorly. Pronotum with several rather inconspicuous small round signa (glabrous areas) in posterior half (Fig. 12B). Sclerites of venter of prothorax (Fig. 12G) with concentrically arranged asperities and therefore rugulose, not glabrous. Venter of meso- and metathorax (Fig. 12H) rugulose due to dense cover with asperities.

Legs (Fig. 12H) slightly slenderer than those of Ancyronyx minerva and with asperities at coxae, trochanter and femora.

Abdomen (Figs 4; 12A, H–K) without noticeable dorsosagittal carinae except for subanterior portion of segment IX (Fig. 12J); squamose setae at posterior rim of segments I–VIII large and overlapping (Fig. 12I). Ventral sclerites of segment I with sagittal ridge almost reaching up to posterior margin, distinctly longer than 1/3 of segment length (Fig. 12H)

Operculum (Fig. 12J) with deep median depression. Apex of segment IX (Fig. 12K) truncate to very slightly emarginate.

Variation between larval instars.

The few available prefinal instar specimens vary from the description above by relatively slenderer thoracic and abdominal segments, the relatively longer posterolateral projections, the distinctly shorter and broader legs and fewer setae on tibiae and femora.

Larval differential diagnosis.

The species can most easily be distinguished from Ancyronyx minerva which looks superficially most similar by the colour pattern of ventral head, pronotum and last abdominal segment and the longer median crest of the first abdominal segment venter.

Distribution.

Known from Palawan island.