Hydrothassa (Hydrothassa) fairmairei (Brisout, 1866)

Baselga, Andrés & Novoa, Francisco, 2006, Description of the mature larva of Hydrothassa fairmairei (Brisout) (Coleoptera: Chrysomelidae: Chrysomelinae) and key to the larvae of the genus, Zootaxa 1344, pp. 23-31 : 25-27

Hydrothassa (Hydrothassa) fairmairei (Brisout, 1866) , mature larva

( Figs. 1–6 )

Material examined. SPAIN. A Coruña, Oroso, Sigüeiro, (UTM 29TNH4457), 250 m, 5 May 2004, 2 mature larvae; Lugo, Sierra de Xistral, Abadín, Valdeinfernos (UTM 29TPH2109), 600 m, 17 July 2002, 9 mature larvae.

Description. Habitus as in Fig. 1 . Length: 5.7–6.6 mm. Body eruciform, moderately convex and slightly arched in preserved specimens. Inter-tubercular plates and tubercles concolor, red brown in dorsal region, light brown in ventral region. Head. Hypognathous, well sclerotized. Color red brown. Epicranial suture well developed and long, frontal arms distinct, V-shaped and almost straight ( Fig. 2 ). Endocarina present, extending to clypeus. Vertex bearing 3 pairs of setae (v1, v3, v6). Frons with 3 pairs of setae (f3, f4, f6). Antennae short and well sclerotized, three-segmented: first joint highly transverse, bearing 4 placoid sensilla (only 2 visible in frontal view, Fig. 3 ); second joint 1.5 times longer than wide, bearing a large conical membranous sensillum and 6 minute setae; distal joint narrow, bottle-shaped, with membranous apex bearing 5 highly minute setae (central one three times larger than the others) and 1 placoid sensillum (not visible in frontal view). Stemmata arranged in two groups, 1 pair located below the base of antenna and 2 pairs behind the antenna. Clypeus with 2 pairs of setae. Mouthparts. Labrum ( Fig. 2 ) bearing 1 pair of placoid sensilla and 2 pairs of setae on upper surface, one near middle, the other near lateral sides; anterior border with a median wide U-shaped notch and 3 stout setae on each side. Mandibles symmetrical, 4-toothed, bearing 2 setae on external face and 1 placoid sensillum on dorsal side. Maxillae ( Fig. 4 ): cardo transverse, without setae; stipes elongate, with 2 large setae near base of maxillary palp; mala bearing 9–11 setae on internal margin and apex, basal setae longer than apical ones; maxillary palpi 4- segmented, first joint almost as long as wide, bearing 2 long setae basally in ventral side and a placoid sensillum in dorsal side (not visible in Fig. 4 ), second joint transverse with 1 minute seta on external side, third joint longer than wide with 1 seta and 1 placoid sensillum on internal face, and two setae on external side, and fourth joint conical with 1 minute seta on internal face and membranous apex bearing 9–11 highly minute setae. Labium ( Fig. 4 ) with postmentum membranous, bearing 3 pairs of setae, anterolateral one very short; prementum with 4 pairs, 2 posterior and 2 anterior to labial palpi, one of the former much longer than the others; labial palpi 2-segmented, first joint transverse, distal joint conical with membranous apex bearing 8–9 highly minute setae. Thorax. Tubercles poorly delimited. Prothorax with tubercles D (dorsal), DL (dorsolateral) and EP (epipleural) fused together in a pronotal sclerite ( Fig. 6 ), pronotum (D-DL-EP) bearing 9 pairs of primary setae along with 1 pair of shorter setae and 3 pairs of extremely minute ones; tubercle P (pleural) with 1 setae; ventral region with midventral tubercle ES (eusternal) separated in two halves, each one fused with tubercle SS (sternellar). Each fused tubercle SS-ES bears 2 setae. Meso- and metathorax with 4 tubercles on each side of dorsal region: Dai-Dae (dorsal anterior interior and dorsal anterior exterior fused together, bearing 1 seta), Dpi-Dpe (dorsal posterior interior and dorsal posterior exterior fused together, 1 seta), DLai-DLpi (dorsolateral anterior interior and dorsolateral posterior interior fused together, 1 long seta and 2 smaller ones), and DLae-DLpe (dorsolateral anterior exterior and dorsolateral posterior exterior fused together, 3 setae, one of them extremely minute) enclosing the eversible gland; epipleural region with 2 tubercles, EPa (epipleural anterior, 1 seta) and EPp (epipleural posterior, 1 seta); mesothoracic spiracle very close to EPa tubercle; P tubercle bearing 1 seta; SS well developed, bearing 1 seta; ES tubercle bearing a pair of setae. Legs. All pairs similar in size; trochantin ( Tr) located in front of P tubercle ( Fig. 6 ), bearing 2 extremely minute setae in anterior half; prothoracic trochantin also with 1 larger seta in postero-ventral angle; coxa 1.5 times longer than wide in lateral view ( Fig. 5 ), with 3 large setae on dorsal face and 3–4 shorter ones in lateral declivities; trochanter triangular, with 2 setae on each side, 5 placoid sensilla near coxal articulation on anterior side and 2 on posterior side; femur wider apically than basally in lateral view, with 2 setae dorsally, 3 ones on each lateral declivity and 1 placoid sensillum on anterior side; tibio-tarsus twice longer than wide, bearing 4 setae dorsally, 1 on each side and 1 ventrally; unguis wide basally, curved apically, bearing 1 seta on lower side. Abdomen. Segments 1–6 with only 2 large tubercles on each side of dorsal region ( Fig. 6 ): Dpi-Dpe (2 setae, one of them minute) and DLae-DLpe (2 setae, one of them minute) enclosing the eversible gland; Dai-Dae and DLai-DLpi lacking; epipleural region with tubercle EP bearing 2 setae; spiracle located between EP and DLae- DLpe tubercles; P tubercle with 2 setae, one of them minute (lacking in segment 1); sternal region presents the following tubercles: SS (3 setae, excepting segment 1 with only 2 setae), ES (1 pair of setae). Segment 7–9 with tubercles SS and ES fused together; segment 8 and 9 also with dorsal and dorsolateral tubercles fused together; segment 10 forming anal pseudopod.

Distribution and ecology. Hydrothassa fairmairei (Brisout) is an Iberian endemic distributed in the northern half of the peninsula reaching central mountains of Spain to the south ( Marseul, 1883; Petitpierre, 1981; Petitpierre & Doguet, 1981; Garc ί a-Ocejo, et al., 1992; Garc ί a-Ocejo & Gurrea, 1995; Baselga & Novoa, 2000a; 2000b; Vives, 2000; Baselga & Novoa, 2006), reaching also Portugal ( Oliveira, 1893) and the French Pyrenees to the north (Tempẻre, 1971). The recorded host plants are Ranunculaceae belonging to the genera Caltha L. and Ranunculus L.: Caltha palustris L. ( Baselga & Novoa, 2000a and other personal observations in Galicia, unpublished), Ranunculus aquatilis L. (Garc ί a- Ocejo & Gurrea, 1995). We have also collected this species on other species of Ranunculus (unpublished) especially Ranunculus repens L., including the larvae described in this paper.

Figures

FIGURE 1. Habitus of Hydrothassa fairmairei, mature larva from Valdeinfernos. Length = 6.4 mm.

FIGURE 2 – 5. Hydrothassa fairmairei, mature larva from Valdeinfernos. (2) Head, frontal view. (3) Antenna, frontal view. (4) Maxillae and labium, ventral view. (5) Leg, lateral view. Scale bars = 0.1 mm.

FIGURE 6. Hydrothassa fairmairei, mature larva from Valdeinfernos: location of tubercles and body chaetotaxy, right side. Pr, prothorax; Ms, mesothorax; Mt, metathorax; A 1 - A 10, abdominal segments 1 – 10. See text for definition of tubercles abbreviations. Scale bar = 0.5 mm.