Anticura flinti Spangler, 1979

Minoshima, Yûsuke N., Fikáček, Martin, Gunter, Nicole & Leschen, Richard A. B., 2015, Larval Morphology and Biology of the New Zealand-Chilean Genera Cylomissus Broun and Anticura Spangler (Coleoptera: Hydrophilidae: Rygmodinae), The Coleopterists Bulletin 69 (4), pp. 687-712 : 693-699

Anticura flinti Spangler, 1979

( Figs. 2–8 )

Material Examined. CHILE: Los Lagos: 7 L1, 16 L2, 10 L3 ( NMPC, including molecular voucher MF793.2, KMNH): Parque Nacional

Puyehue ( Fig. 2H ), Anticura, Río Anticura between Salto Pudú and confluence with Río Golgol, 40°40.0–40.5′ S 72°9.9 –10.6′W, floating moss from stone in the river (submerged + just above water) ( Fig. 2H , white bar) and the flood debris accumulated in logjam ( Fig. 2I , white bar) ( CH 29), 350–460 m, 6–9.xii.2013 lgt. Fikáček, Kment & Vondráček lgt. La Araucanía: 21.8 km SE of Pucón, Río Palguín ( Fig. 2G ) at 9.km of Ruta S-941, 39°24.6′ S 71°46.4′ W, 650 m, floating of moss (submerged + directly above water) from stones in the stony mountain river ( Fig. 2F, G , white bar) ( CH 21), 1.xii.2013, lgt. Fikáček, Kment & Vondráček; 2 L3 ( NMPC): Parque Nacional Nahuelbuta ( Fig. 2J ), 2.2 km N of Pehuenco, Estero Aqua de Los Gringos, 37°48.5′S 73°0.7′W, 1160 m, floated from moss at water level or in the splash zone at stones at sides and in the middle of a mountain stream ( Fig. 2K , white bar) ( CH 37), 11–12.xii.2013, lgt. Fikáček, Kment & Vondráček.

Description. General Morphology. Third Instar. Body ( Fig. 2B–D ) moderately thick, nearly parallel-sided, lobate laterally; widest between abdominal segments 2–5. Eight pairs of spiracles present laterally on tubercles on mesothorax and abdominal segments 1–7, 1 pair on abdominal segment 8 enclosed in spiracular atrium. Color dark brown with slightly paler tubercles and yellowish brown to brown sclerites. Head: Head capsule ( Figs. 6 , 8A ) subtrapezoidal, widest medially. Cervical sclerite large, elongate subquadrate. Frontal lines indistinct, only basal half slightly visible; coronal line short. Basal part of frontale bearing densely arranged small, tooth-like projections. Six stemmata on each anterolateral portion of head capsule. Posterior tentorial pits present close to junction of submental sulcus and gular sulcus. Clypeolabrum ( Fig. 6C ) very slightly asymmetrical. Nasale with 2 teeth closely aggregated, projecting beyond epistomal lobes. Lateral lobes of epistome large, projecting anteriorly. Anterior margins of the lobes slightly to weakly sinuate; inner part of the lobes bearing fine cuticular teeth and trichoid cuticular projections on left side, fine trichoid cuticular projections on right side. Antenna ( Fig. 7A–B ) 3-segmented, rather slender, surface smooth. Antennomere 1 wider and longer than antennomere 2; antennomere 3 shortest and narrowest. Antennal sensorium present, small. Mandibles ( Fig. 7C–D ) almost symmetrical, with 2 inner teeth each. Apical inner tooth larger than basal one. Inner face of incisor area distally of inner teeth and between them smooth, without distinct serration. Inner face of mandible basally of basal inner tooth almost straight. Maxilla ( Fig. 7E–F ) 6-segmented, longer than antenna. Cardo large, irregularly shaped. Stipes the longest and widest, distinctly longer than palpomere 1–4 combined. Outer face of stipes without densely arranged, short, trichoid cuticular projections dorsally (this part of second/third instars bearing a series of stout setae, bearing few projections). Maxillary palpus short, 4-segmented. Palpomere 1 widest, incompletely cylindrically sclerotized dorsally. Inner process sclerotized. Palpomeres 2 wider than palpomere 3, palpomere 4 narrowest. Intersegmental membranes between palpomere 1 and 2 and 2 and 3 bearing fine trichoid cuticular projections dorsally. Labium ( Fig. 7G–H ) well-developed. Hypopharyngeal lobe absent. Submentum fused to head capsule, large, subpentagonal; submental sulcus only partly visible. Mentum subquadrate, slightly longer than wide. Dorsal surface with densely arranged cuticular teeth. Prementum subquadrate, transverse, anterior part wider than posterior part. Anterior membranous area of prementum with densely arranged, short trichoid cuticular projections behind palpomere 1. Ligula well-developed, median part sclerotized as ring. Labial palpus long, longer than ligula; palpomere 1 wider than palpomere 2 and shorter than ligula, bearing extremely fine, trichoid cuticular projections; intersegmental membrane between palpomere 1 and 2 bearing short, trichoid cuticular projections dorsally and laterally. Thorax: With several pairs of sclerites; meso- and metanotum tuberculate laterally. Prothorax slightly wider than head capsule. Proscutum formed by 1 large plate subdivided by fine sagittal line, anterior part weakly sclerotized; median part with transverse groove, lateral part with convex portions. Proscutal plate shagreened, covered with fine granules. Prosternal sclerite ( Fig. 8B ) subpentagonal, fine sagittal line visible only at base, anterior part weakly sclerotized; bearing numerous short setae anteriorly and laterally. Mesonotum with 3 pairs of sclerites. Anterior 2 sclerites small, narrow, transverse; 1 mesally, 1 laterally. Posterior sclerite large, transverse, subquadrate. Sclerites adjacent mesally; anterior part bare, with transverse ridge; posterior part shagreened, bearing fine granules. Metanotum with 3 pairs of sclerites. Anterior sclerite very small, narrow on anterolateral part (very indistinct in second instar, absent in first instar). Median sclerite large, subquadrate, transverse; anterior part of median sclerite bare, with transverse ridge. Posterior part of median sclerite shagreened, bearing fine granules posteromesally; posterior sclerite finely shagreened, narrow, transverse, on posterolateral part. Legs ( Fig. 8C ) moderate in length, slightly visible in dorsal view, 5-segmented; all 3 pairs similar in shape. Abdomen: Ten-segmented, slightly tapering posteriorly, bearing 2 transverse rows of tubercles of several sizes, lateral sides with tubercles ( Fig. 8D ); segments 1–7 similar in shape and size. Dorsal sclerites on segment 1 possibly absent or very weakly sclerotized. Segment 1 with anterior row of 4 very small tubercles dorsally, posterior row of 4 large tubercles. Lateral face with 6 projections, 5 anteriorly, 1 posteriorly. Spiracle present on apex of dorsal-most projections of anterior ones. Segments 2–7 similar to segment 1 but dorsal sclerites seem absent, but a pair of very small, bare portions anteromesally. Anterior row of 4 large tubercles dorsally, lateral 2 smaller than median 2, often indistinct. Posterior row on segment 7 with 2 tubercles. Spiracular atrium ( Fig. 8D ) on segment 8 with large, oval dorsal plate bearing small setae; plate partially pigmented, thus seemingly composed of 2 sclerites. Procercus incompletely sclerotized, with 2 rather long and 1 short seta. Spiracular atrium on segment 9 trilobed, partly sclerotized dorsally. Median lobe transverse, lateral lobe without acrocercus; 1 pair of membranous projections between median lobe ante lateral lobes. Urogomphi short, 1-segmented; prostyli absent.

Second Instar. Very similar to third instar. Head: Frontal lines clearly visible as in first instar ( Fig. 2B–D ; see description of first instar). Antenna slightly proportionally stouter than in third instar.

First Instar. Very similar to third instar ( Fig. 2A ). Head: Frontal lines clearly visible, lyriform, converged at base, coronal line very short ( Fig. 3 ). Antenna ( Fig. 4A–B ) slightly proportionally stouter than in second instar. Maxilla ( Fig. 4E–F ). Outer face of stipes bearing densely arranged, small, trichoid to tooth-like cuticular projections dorsally (this part of second/third instars bearing a series of stout setae).

Chaetotaxy of Head of First Instar. Frontale: Fig. 3A, C . Central part with numerous short to moderately long setae, FR1 indistinguishable from them by morphology, likely situated close to bend of frontal line (based on comparison with Cylomissus , see below). FR2 pore-like situated between FR1 and FR3, close to FR3; FR3 short stout seta situated anteromesally to FR2, very close to FR8. Moderately long seta FR5 and long seta FR 6 in area anterolateral to FR2 and posterolateral to FR3. Oval pore-like sensillum FR4 situated anteromesally to FR6, mesally to antennal socket. Rather short seta FR7 close to inner margin of antennal socket. Short seta FR10, long seta FR9, and pore-like sensillum FR14 slightly anteromesal to antennal socket; FR10 anterior to FR4; FR9 between FR10 and FR14; FR14 laterally to FR9. The area mesally of antennal socket with several short additional setae. Distribution of sensilla on epistomal lobe nearly symmetrical; pore-like sensillum FR11 close to emargination between nasale and epistomal lobe, FR13 anteromesally of FR11 and anteriorly to FR9, FR11 and FR13 not closely aggregated; short seta FR12 situated medially on anterior margin of epistomal lobe. Rather long seta FR8 behind nasale. Pore-like sensillum FR15 on base of nasale. Nasale with 6 short stout setae (gFR1), 4 on projecting part, 1 on each side laterally of the nasal tooth. Left epistomal lobe with 8 setae excluding FR12 (gFR2); short seta in emargination between nasale and epistomal lobe, 2 rather stout setae on mesal portion of anterior margin, 5 stout to fine setae on anterolateral margin of the lobe. Parietale: Fig. 3A–B . Dorsal to lateroventral surface with very numerous, minute to rather long additional trichoid sensilla, situated along frontal line, around, posteriorly and anteriorly of stemmata, and laterally on posterior 2/3; scale-like additional setae absent. Dorsal surface with a group of 5 sensilla (PA1–5) forming irregularly longitudinal row in posterior part of parietale; PA1–2 and 4–5 short, stout setae, PA3 pore-like. PA6 porelike, located laterally to coronal line. PA8 (broken in examined specimen, but likely a seta) anterolateral to mesal-most anterior stemma, close to frontal line. PA10 pore-like, between mesal-most anterior and posterior stemmata, short seta PA11 between median stemmata. PA7 and PA12–17 forming irregularly transverse row on median part of lateral face of parietale. PA7 rather long seta behind mesal-most posterior stemma; PA12 long seta behind posteromedian stemma; long seta PA13 close and lateral to PA14. PA14–17 on lateroventral surface; PA14 seta, PA15 pore-like, behind PA14; PA16 very long seta, situated ventrally to PA14–15; PA17 pore-like. PA18 and PA30 on ca. posterior third of head capsule; PA18 very long seta, PA30 pore-like sensillum. PA9, PA19 and PA22 situated on anterior corner of head capsule, PA9 most dorsally, PA22 most ventrally (PA20–21 not found in examined specimen); PA9 very long seta, PA19 pore-like sensillum, PA22 long seta. PA23–25 on ventral mandibular articulation; PA23–24 laterally to PA25, PA24 between PA23 and PA25. PA26–29 on median part of ventral surface of parietale, forming longitudinal row divergent anteriad, not equidistant from each other; PA26 long seta, PA28 seta, possibly very long (compared with third instar), PA27 and PA29 pore-like sensilla; PA28–29 closely aggregated, PA27 anteriorly to them, PA26 largely isolated from the latter, situated in anterior fourth of parietale. Antenna: Fig. 4A–B . Antennomere 1 with 5 pore-like sensilla (AN1–5); AN1 situated dorsally on outer face posterolaterally to AN2; AN2 on median part; AN3–5 apical to subapical, AN3 on outer face, AN4–5 on inner face. Antennomere 2 with 1 pore-like sensillum (AN6) situated dorsally in distal fourth of sclerite; setae AN7–11 and sensorium SE1 on intersegmental membrane between antennomeres 2 and 3; AN7–8 and SE1 on lateral face, AN7–8 minute, basally to SE1, SE1 ca. 0.3X as long as antennomere 3, stout, conical; AN10–11 on inner face, AN10 very long, AN11 short, both setae close to each other. Antennomere 3 with group of sensilla (gAN) in apical membranous area; 1 very long, 1 long seta, others minute. Mandibles: Fig. 4C–D . Mandible with 3 pore-like sensilla (MN2–4) on median part, forming triangular group; MN3 mesal to MN2, posteromesal to MN4, MN4 on lateral face, anterior to MN2–3; MN2 between MN1 and MN3; MN1 short seta at ca. midlength of lateral face. Minute seta MN5 subapical on lateral face, candidate for minute pore MN6 on subapical part of inner face. Maxilla: Fig. 4E–F . Cardo with 1 short ventral seta ( MX 1). Inner face of stipes with a row of rather short setae densely arranged on dorsal part (gMX2), slightly increasing in size toward distal margin, most of them (except basal-most setae) bearing subapical tooth, MX 7 short and stout dorsal seta at base of gMX2, stouter than adjacent gMX2 setae. Ventral surface of outer face of stipes with 3 primary sensilla ( MX 4–6) closely aggregated on distal part of sclerite, MX 4 pore-like, MX 5–6 long setae. Pore-like sensilla MX 2–3 situated ventrally, both ca. at basal 2/5 of length, MX 3 mesad MX 2. Dorsal surface of palpomere 1 with 1rather short, stout seta ( MX 16) situated on inner face. Three sensilla ( MX 12–14) ventrally on distal part of sclerite; MX 12 pore-like on lateral face, MX 13–14 long setae on median part. Pore-like sensilla MX 15 and MX 17 situated on membrane below inner appendage, MX 17 dorsally, MX 15 ventrally. Inner appendage with 1 very long seta and 1 short stout seta apically (gAPP). Palpomere 2 with 2 pore-like sensilla ( MX 18 and MX 19) and 1 minute seta ( MX 27); MX 18 situated ventrally on lateral part of anterior margin of sclerite; MX 19 situated dorsally on inner face of intersegmental membrane between palpomeres 2 and 3; MX 27 situated basally on lateral face. Palpomere 3 with 2 long setae ( MX 21 and MX 23) and 2 pore-like sensilla ( MX 20 and MX 22); MX 21 and MX 22 situated ventrally, MX 22 basal to MX 21; MX 20 and MX 23 on lateral part, both closely to distal margin of sclerite, MX 23 dorsad MX 20. Palpomere 4 with 1 seta ( MX 24) situated basally on inner face and with small digitiform sensillum ( MX 25) and pore-like sensillum ( MX 26) apically on outer face of sclerite. Apical membranous area of palpomere 4 with several minute setae (gMX). Labium: Fig. 4G–H . Submentum with 2 pairs of setae (LA1–2) on anterolateral portion; LA1 very long on lateral margin, LA2 short on anterior margin. Ventral surface of mentum with 1 pair of rather short setae (LA3) and pore-like sensilla (LA4), LA3 posteriorly to LA 4 in basal half/third of sclerite, LA4 close distal margin of sclerite. Prementum and its anterior membranous area with 5 pairs of sensilla (LA5–9). LA5 minute seta at laterobasal margin of sclerite, LA6–7 ventral, on anterior margin of sclerite, LA6 very long seta mesal to LA7, LA7 pore-like. LA8–9 dorsal on median part, LA8 pore-like, on anterior margin of sclerite, LA9 transversely pore-like on median portion of membranous area. Ligula with 3 pairs of sensilla (LA10–12); LA10 long seta, lateral to midline; LA11 pore-like, subapical on ventral surface; LA12 pore-like, digitiform, apical on dorsal surface. Palpomere 1 with 2 sensilla (LA13–14); LA13 minute seta, situated ventrally on basal part; LA14 pore-like, dorsal on intersegmental membrane between palpomeres 1 and 2. Palpomere 2 with pore-like sensillum LA15 situated on distal margin on outer face of sclerite. Apical membranous area of palpomere 2 with minute setae (gLA; not examined in detail).

Chaetotaxy of Head of Second Instar. Head: Similar to third instar. Antenna: Fig. 5A–B . Similar to first instar, sensorium (SE1) proportionally smaller, dorsal face of antennomere 1 with several additional minute setae. Mandibles: Similar to third instar. Maxilla: Fig. 5C–D . Similar to first instar. Setae of inner face of stipes (gMX2) more numerous, basally not distinguishable from MX 7; dorsal face of stipes with additional irregular row of long stout setae parallel to gMX2 submesally; lateroventral surface with numerous scattered additional minute setae; outer face with numerous long stout additional setae throughout the length, some of them simple, some of them with subapical tooth. Maxillary palpus without additional sensilla, MX 23 slightly more basal than in first instar, MX 25 relatively longer than in first instar. Labium: Similar to third instar.

Chaetotaxy of Head of Third Instar. Head: Fig. 6 . With many more additional setae, hence multisetose and with primary setae very difficult to recognize from secondary/additional ones. Arrangement of primary sensilla which may be recognized very similar to that of first instar. Ventral surface with scattered short setae anteriorly and in area between and behind PA26–29. PA28 anteriorly to PA 29 in contrast to first instar (but may represent variation rather than inter-instar difference, as few larvae were examined). Base of epistomal lobes anterior to antennal sockets with several short additional setae. Antenna: Fig. 7A–B . Dorsal surface of antennomere 1 with a few minute secondary setae medially. Mandible: Fig. 7E–F . Outer face between basal and apical fifths of the length with numerous additional short setae. Maxilla: Fig. 7C–D . Dorsal inner face with a irregular row of stout secondary setae with subapical tooth medially; outer face with densely arranged stout secondary setae with subapical tooth; small secondary setae distributed anterior part of ventral surface and whole lateral surface. Labium: Fig. 7G–H . Distal margin and whole dorsolateral surface of mentum with numerous long stout additional setae.

Figures

Fig. 2. Anticura flinti. A) First instar, dorsal view, B–D) Third instar, dorsal, lateral, and ventral views, E) Adult, F) Detail of microhabitat in Parque Nacional Villarica, with the plastic box used for floating the specimens from moss, G) Parque Nacional Villarica, Río Palguín, 21.8 km SE of Pucón, Chile, H) Parque Nacional Puyehue, Río Anticura, Chile, I) Logjam at side of the river from which the accumulated debris was also floated and some Anticura collected, J) Parque Nacional Nahuelbuta, Estero Agua de Los Gringos, Chile, K) Detail of microhabitat Parque Nacional Nahuelbuta from which Anticura were collected. Photograph J by D. Vondráček.

Fig. 3. Anticura flinti, first instar, head capsule. A) Dorsal view, B) Ventral view, C) Anterior margin, dorsal view.

Fig. 4. Anticura flinti, first instar. A–B) Antenna, dorsal and ventral views, C–D) Left and right mandible, dorsal view, E–F) Maxilla, dorsal and ventral views, G–H) Labium, dorsal and ventral views.

Fig. 5. Anticura flinti, second instar. A–B) Antenna, dorsal and ventral views, C–D) Maxilla, dorsal and ventral views.

Fig. 6. Anticura flinti, third instar, head capsule. A) Dorsal view, B) Ventral view, C) Anterior margin, dorsal view.

Fig. 7. Anticura flinti, third instar. A–B) Antenna, dorsal and ventral views, C–D) Left and right mandible, dorsal view, E–F) Maxilla, dorsal and ventral views, G–H) Labium, dorsal and ventral view.

Fig. 8. Anticura flinti, third instar. A) Head, dorsal view, B) Prosternal sclerite, ventral view, C) Metathoracic leg, ventral view, D) Abdominal segments 8–10 with spiracular atrium, dorsal view.