Ancyronyx patrolus 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 : 63-66

Ancyronyx patrolus Freitag & Jaech, 2007 Figs 615 A–K

Ancyronyx patrolus Freitag & Jäch, 2007: 41, 44-46 (adult description).

Material examined.

1♂ (ZSM [FR032]) PHIL.: Busuanga, Coron, San Nicolas/Borac, "7Falls" mount. creek; riffle & pool; gravel, boulders, CPOM, sec. forest/rural; c.50m asl, 12°03'11"N, 120°15'28"E 02.2.1995, leg. Freitag (165)M; 4L (0.23, 0.31, 2 × 0.32) (CFP) "PHIL.:Palawan, El Nido, Bgy. Pasadeña Nagkalit-Kalit Falls, small mountain river, degr. prim. forest, rocks, gravel, wood litter, c. 11°15'N, 119°26'E 14.10.1994, leg. Freitag (112)M"; 1L (0.19) (CFP) "PHIL.: Palawan, P. Princesa Panaguman R. 10°15'09"N, 118°58'03"E 17.5.2001, leg. Freitag (PR1)D"; 21 exs.; 1L (0.30) (NMW) "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"; 2L (0.30, 0.32) (CFP) "PHIL.: Palawan, P.Princesa; Concepcion, Taranaban R. trib.;mount.creek c.8km upstr.; dist. prim. forest; riffle;rocks, boulders,roots; c.450m asl 10°05'N, 119°01'E, 28.1.1995 leg. Freitag (16f)M"; 2♀♀, 1L (0.26) (CFP, SMTD) "PHIL.: Palawan, P.Princesa; Concepcion, Tagpaya, Camp Aga, Taranaban R. trib.; mount.creek c.8km upstr. Highw., dist. prim. forest; riffle;rocks, boulders, roots; c.450m asl 10°05'N, 119°01'E, 26.4.1995 leg. Pangantihon (16f)M"; 1L (0.30) (CFP) "PHIL.: Palawan, P. Princesa, Bacungan, Bisor Riv.,6km NW Highw. km23, mount. riv., sec. forest; riffle, boulders, gravel, wood, mos; algae, c. 9°57'42"N, 118°41'47"E 22.1.1995, leg. Freitag (140b)M";15L (0.26, 0.27, 2 × 0.30, 5 × 0.31, 0.32, 5 × 0.33) (NMW) "PHIL.: Palawan, P. Princesa, Irawan River, 6km NW of PPC, 2km upstream of water plant 9°49'N, 118°39'E 06.4.1994, leg. Freitag (60)M"; 1L (0.25) (CFP) "PHIL.: Palawan, P. Princesa, Iwahig, Salomon Riv.; rural near sec. forest, riffle, boulders, gravel, wood; 9°46'59"N, 118°40'53"E 24.1.1994, leg. Freitag (159)M"; 1♂, 4♀♀, 18L (0.20, 0.29, 0.21, 0.30, 6 × 0.32, 6 × 0.31, 2 × 0.33) (NMW, ZSM [FR005, FR006]) " PHIL.: Palawan, P. Princesa, Iwahig, Balsahan Riv., upstr.dam; riffle, boulders, gravel, wood, moss; 9°46'36"N, 118°39'55"E 24.1.1995, leg. Freitag (20)M"; 5L (0.25, 0.28, 2 × 0.30, 0.31) (PCSD) "PHIL.: Palawan, P.Princesa; Junction to Napsan, 8km SW PPC; 20m S Binuan Bridge,gravel, root packs, riffle, sec.veget. c.20m asl 9°43'N, 118°40'E, 08.2008 leg. Freitag (22b)M"; 3L (0.26, 0.30, 0.32) (SMTD, ZSM) "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"; 1♀, 4L (0.28, 2 × 0.31, 0.32) (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)"; 1L (0.30) (CFP) "PHIL.: Palawan, Narra, 5 km W town proper, Taritien River, riffle, boulders, gravel, leaf litter c. 100m asl. 9°19'11"N, 118°22'35"E 17.4.2010, leg. Freitag et al. (182a)".

Larval diagnosis (based on 6th instar).

Colour as in Fig. 6: almost entirely dark-brown; antennae, area of explanate lateral thoracic and abdominal gutter, lateral head portions and legs (except for darkened area around claw insertation) pale brown or yellowish. Mouthparts and surrounding portions of head capsule almost black. Without pale pattern at dorsal thoracic and abdominal segments; only apex of abdominal segment sightly paler. Ventral side pale brown.

HW 0.32 mm; entire larva up to 3.5 mm long. Body shape as in Ancyronyx minerva , except for the following: dorsosagittal carinae at the posterior portions of abdominal segments IV–VIII and the entire length of segment IX very distinct (Figs 15A, B). Setiferous tubercles at dorsal side very prominent and protruding (Figs 15A, B) as in Ancyronyx pseudopatrolus . Ventral side smoother, with scattered setae (Fig. 15I).

Head as in Fig. 6 and Figs 15 C–F, similar to that of Ancyronyx pseudopatrolus . Glabrous area with stemmata slightly exposed. With few short, acuminate setae on each side and a dorsolateral pair of long double setae (Fig. 15C). Frontal suture U-shaped (Fig. 6). Fasciculate setae at subbasal fringe of clypeus very long (Figs 15C, F). Gula (Fig. 15D), labium (Figs 15D, E), maxillae (Figs 15D, E) and labrum (Figs 15D, F) as in Ancyronyx minerva . Antennae (Fig. 15F) as in Ancyronyx punkti .

Pro-, meso- and metathorax as in Figs 6, 15G and Fig. 15H. Dorsal thoracic segments with conspicuous small round signa (arranged as in Fig. 15G) and a distinct sagittal line (sagittal line partly fused with signa). Thoracic venters (Fig. 15H) rather smooth as in Ancyronyx minerva . Legs (Figs 15 H–J) similar to those of Ancyronyx minerva ; inner side of tibiae and femora with longitudinal rim of spinous setae (Fig. 15J); all other parts with scattered squamose setae.

Abdomen (Figs 6; 15A, B, I, K) with distinct dorsal sagittal line and slightly elevated surrounding portions in segments I–IV. Dorsosagittal carinae at the posterior portions of abdominal segments IV–VIII distinctly elevated, somewhat drop-shaped and densely covered with setiferous tubercles (Fig. 15B). Sagittal ridge of ventral sclerite of first segment distinctly shorter than 1/2 of segment length (Fig. 15I). Apex of segment IX emarginate. Operculum (Fig. 15K) elongately subtrapezoidal, medially moderately impressed, rugulose.

Variation between larval instars.

Specimens of 4th and 5th instar vary only little from the final larval instar. The species typical dorsosagittal carinae of the posterior abdominal segments are very distinct. However, the emargination of the abdominal segment IX` apex is not conspicuous, the overall colour is paler, the thoracic and abdominal segments are relatively narrower, the legs are slightly shorter and broader and the setae on tibiae and femora are fewer and not well arranged in rims.

Larval differential diagnosis.

The species can clearly be distinguished from other Palawan species by the lack of pale dorsal colour patches and its highly elevated dorsosagittal carinae which is most conspicuous at the posterior portion of abdominal segment VIII where it appears as a drop-shaped protuberance.

Distribution.

Only known from Palawan and Busuanga.