Tychius (s. str.) parallelus (Panzer, 1794)

Skuhrovec, Jiří, Gosik, Rafał & Caldara, Roberto, 2014, Immatures of Palaearctic species of the weevil genus Tychius (Coleoptera, Curculionidae): new descriptions and new bionomic data with an evaluation of their value in a phylogenetic reconstruction of the genus, Zootaxa 3839 (1), pp. 1-83 : 7

Tychius (s. str.) parallelus (Panzer, 1794)

Caldara 1990: 85.

Material examined. 2 larvae from pods of Cytisus scoparius (L.) Link., collected 14.viii.1989 at Navacerrada , Sierra de Guadarrama, Madrid ( Spain), 1500 m, leg. A.J. Velázquez de Castro, determined by association with adults collected on the same plant .

Differential diagnosis. See Table.2 .

Description of mature larva. COLORATION. Head brown to dark yellow. All thoracic and abdominal segments light yellow.

HEAD CAPSULE AND MOUTH PARTS. Head width: 0.45–0.51 mm (see Table. 1 ). Endocarinal line present, reaching middle of frons. Des 1 located almost in central parts of epicranium; des 2 absent; des 3 located along frontal suture; des 4 absent; des 5 located laterally ( Fig. 1 ). Fs 1 and fs 2 absent; fs 3 very short, located medially; fs 4 located anteromedially (along epistoma); fs 5 located anterolaterally (along epistoma), 3 to 4 times longer than fs 3 ( Fig. 1 ). Both les almost as long as des 3; ves very short. Postepicranial area with 1 minute pes. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla ( Fig. 4 ).

Labrum ( Fig. 5 ) approximately 2.5 times as wide as long; lms 1 slightly longer than lms 3, lms 2 distinctly longer than lms 1; anterior margin slightly sinuate. Clypeus ( Fig. 5 ) 3.5 times as wide as long; with 2 pairs of short cls of same length, located posterolaterally; anterior margin slightly rounded inside. Epipharynx ( Fig. 6 ) with 3 pairs of als, different in length; with 2 pairs of short ams, ams 2 distinctly shorter than ams 1; with 3 relatively short and finger-like mes; labral rods short, kidney-shaped, strongly converging posteriorly. Mandibles ( Fig. 3 ) with 2 short mds, different in length. Maxilla ( Fig. 2 ): stipes with 1 stps, and with 2 pfs of equal length; mala with 5 slightly curved dms, different in length; with 4 vms, moderately long and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1.4; basal palpomera with 1 short mxps; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum ( Fig. 2 ) almost rounded, with 1 prms; margin of ligula slightly curved inside; ligula with 2 lig; premental sclerite distinct. Postmentum ( Fig. 2 ) with 3 pairs of pms different in length.

THORAX AND ABDOMEN. Body length 3.9–4.9 mm (see Table. 1 ), elongate. Abdominal segments I–VI almost equal in length ( Fig. 7 ). Spiracles on abdomen in anteromedian parts of segments (abdominal segments I–VIII).

Chaetotaxy of body rather reduced. Setae moderately short or very short, and light yellow. Thorax. Prothorax ( Fig. 8 ) with 8 prn, 7 macro- and 1 microsetae; 2 moderately long ps of same length; 1 eus. Meso- and metathorax ( Fig. 8 ) with 1 prs; 3 pds, different in length; alar area with 1 very short as; 1 very short ss; 1 eps; 1 ps; and 1 short eus. Each pedal area of thoracic segments well-separated and with 5 pda, different in length (long, moderately long, short). Abdomen. Abdominal segments I–VII ( Fig. 9 ) with 1 prs; 3 pds of different length; 1 ss; 2 eps of different length; 1 ps; and 2 short eus. Abdominal segment VIII ( Fig. 10 ) with 1 prs; 3 pds; 1 ss; 1 ps; and 2 short eus. Abdominal segment IX ( Fig. 10 ) with 1 ds; and 1 sts. Anal lobes on abdominal segment X ( Fig. 10 ) without setae.

Biological observations. Larvae emerged in laboratory from pods collected a few days before (A.J. Velázquez de Castro, pers. comm.). No other information is available.

Remarks. Tychius parallelus lives on different species of Cytisus in central and southern Europe and in Algeria. Biological information on adults are reported by Caldara & Velázquez de Castro (1991).

Figures

FIGURES 1–6. Tychius parallelus mature larva head, antenna and mouth parts: 1—dorsal view (des—dorsal epicranial s., fs—frontal epicranial s., les—lateral epicranial s., ves—ventral epicranial s., pes—posterior epicranial s., at—antenna); 2—right maxilla, dorsal view (dms—dorsal malar s., vms—ventral malar s., mpxs—maxillary palps s., pfs—palpiferal s., stps—stipital s.), prementum and postmentum, ventral view (prms—premental s., pms—postmental s., ligs—ligular s.); 3—right mandible (mds—mandible dorsal s.); 4—antenna; 5—labrum and clypeus (cls—clypeal s., lms—labral s.); 6—epipharynx (ams—anteromedial s., als—anteriolateral s., mes—median s., lr—labral rods).

FIGURES 7–10. Tychius parallelus mature larva habitus: 7—lateral view, 8—lateral view of thoracic segments, 9—lateral view of abdominal segment I., 10—lateral view of abdominal segments VIII–X (prns—pronotal s., prs—prodorsal s., pds—postdorsal s., as—alar s., ss—spiracular s., eps—epipleural s., ps—pleural s., pda—pedal s., eus—eusternal s., ds—dorsal s., sts—sternal s.).