Tychius tibialis Boheman 1843
Creators: name: Skuhrovec, Jiří
name: Gosik, Rafał
name: Caldara, Roberto
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Curculionidae
Tychius
Tychius tibialis

description: Tychius (s. str.) tibialis Boheman, 1843
Caldara 1990: 190.
Material examined. 45 larvae from pods of Trifolium incarnatum L., collected 2.vii.1982 at Levanto, La Spezia province, Liguria (northern Italy), leg. R. Caldara, and 8 pupae reared from larvae collected contemporaneously together with the others, all determined by association with reared adults.
Differential diagnosis. See Tables 2 and 3.
Description of mature larva. COLORATION.Head brown to dark brown. All thoracic and abdominal segments yellow.
HEAD CAPSULE AND MOUTH PARTS. Head width: 0.44–0.52 mm (see Table. 1). Endocarinal line present, exceeding middle of frons. Des 1 located almost in central parts of epicarnium; des 2 located very near frontal suture, near des 3; des 4 located anterolaterally; des 5 located anterolaterally; des 2 and des 4 5 times shorter than des 3 and des 5 (Fig. 203). Fs 1 and fs 2 absent; fs 3 short, located medially; fs 4 and fs 5 located anterolaterally (along epistoma), 4 times longer than fs 3 (Fig. 203). Les distinctly shorter than des 3. Post-epicranial area with group of 4 minute pes. Antennal segment membranous, bearing conical sensorium and 3 very short, triangular, sensilla (Fig. 206).
Labrum (Fig. 207) approximately 1.8 times as wide as long; lms 1 longer than lms 2 and lms 3 (both equal in length); anterior margin doubly sinuate. Clypeus (Fig. 207) 3.2 times as wide as long; with 2 pairs of short cls of same length, and 1 sensillum, all located posterolaterally; anterior margin almost straight. Epipharynx (Fig. 208) with 2 pairs of als, almost of equal length; with 3 pairs of very short ams; with 2 long finger-like and 1 short mes; labral rods kidney-shaped, converging posteriorly. Mandibles (Fig. 205): molar edge jagged with triangular tooth; mds 1–2 short, almost of equal length. Maxilla (Fig. 204): stipes with 1 stps, 2 pfs almost of equal length, and 1 mbs; mala with 4 straight dms, different in length; with 2 vms, short and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1; basal palpomera with 1 short mpxs; distal palpomera with group of some conical, cuticular apical processes. Prementum (Fig. 204) heart-shaped, with 1 prms; margin of ligula slightly sinuate, ligula with 1 lig; premental sclerite distinct. Postmentum (Fig. 204) with 3 pairs of pms, different in length.
THORAX AND ABDOMEN. Body length 2.2–3.1 mm (see Table. 1), elongate. Abdominal segments I–III slightly smaller than abdominal segments IV–VI (Fig. 209). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).
Chaetotaxy of body rather reduced. Setae moderately long or short and light yellow. Thorax. Prothorax (Fig. 210) with 8 prn; 6 macro- and 2 microsetae; 2 moderately long ps of same length; 1 eus. Meso- and metathorax (Fig. 210) with 1 prs; 2 pds, different in length; 1 short ss; 1 eps; 1 ps; and 1 short eus. Each pedal area of thoracic segments well-separated and with 3 long and 3 short pda. Abdomen. Abdominal segments I–VII (Fig. 211) with 1 prs; 2 pds of different length; 1 ss; 2 eps of different length; 1 ps; 1 lsts; and 2 eus. Abdominal segment VIII (Fig. 212) with 2 pds; 1 ss; 2 eps of different length; 1 ps; 1 lsts; and 2 short eus. Abdominal segment IX (Fig. 212) with 1 ds; and 2 sts of same length. Each anal lobe on abdominal segment X (Fig. 212) with 1 very short, feebly visible seta.
Description of pupa. COLORATION. Body yellow.
MORPHOLOGY (Figs. 213–215). Body length 2.2–3.0 mm; widest part 1.4–1.6 mm (see Table. 1). Body elongate. Rostrum long, approximately 4.5 times as long as wide, reaching mesocoxae. Pronotum 1.4 times as wide as long.
CHAETOTAXY (Figs. 213–215). Setae distinct, long or moderately long; unequal in length, light brown; on pronotum and head placed on small protuberances. Head capsule including 1 vs, 1 os, 1 sos, and 1 pas. Rostrum with 1 rs located medially. Setae on head slightly shorter than setae on thoracic and abdominal segments. Pronotum with 2 as, 2 ls, 1 ds, and 1 pls; ds as long as other setae on pronotum. Dorsal parts of meso- and metathorax with 2 setae. Each apex of femora with 1 fes. Setae on abdominal segments I–VIII placed posteromedially and posterolaterally; all abdominal setae located on thorn-like protuberances. Pseudocerci slender, slightly curved inside.
Biological observations. Pupae were found in the cells 8 days later the entrance of larvae into the soil. The duration of the pupal stage was 8 days. Adults emerged at the surface 4–5 days later.
Remarks. Tychius tibialis is a species with a western European and circummediterranean distribution and is distinguishable from the numerous similar species by the colour of the tibiae which is black at its basal portion (Caldara 1990). There were no previous biological data on this species. In the same field, where T. tibialis was collected, also T. curtirostris was collected, but on Trifolium glomeratum.
KEY TO SPECIES OF IMMATURE STAGES OF THE GENUS TYCHIUS
In the following keys it was not possible to include the species described by Clark et al. (1978) due to lack of some diagnostic characters in their description. However, concerning larvae, T. sordidus, T. lineellus, T. tectus, T. soltaui and T. prolixus might be included at point 16, but the next step would be impossible, because Clark et al. (1978) did not recognize stps, pfs and mbs setae. The species of the T. stephensi group (T. stephensi, T. picirostris and T. flavus) might be included at point 2, but the next step would be impossible; in fact Clark et al. (1978) did not include abdominal segment VIII. Concerning pupae every assumption appears impossible, since Clark et al. (1978) did not include a count of ds on the pronotum.
Larvae
1. Meso- and metathorax with 2 pds or variable in segments (Figs. 41, 145, 158, 171, 184, 197, 210).................... 2
- Meso- and metathorax with 3 pds (Figs. 8, 18, 28, 54, 67, 80, 93, 106, 119, 132)................................... 8
2. Abdominal segment VIII with 1 prs (Fig. 173)..................................................... T. decretus
- Abdominal segment VIII without prs (Figs. 43, 147, 160, 186, 199, 212)......................................... 3
3. Abdominal segments I–VII with 2 eps (Figs. 42, 159, 211).................................................... 4
- Abdominal segments I–VII with 1 eps (Figs. 146, 185, 198).................................................... 6
4. Abdominal segments I–VII with 1 ps (Fig. 211)....................................................... T. tibialis
- Abdominal segments I–VII with 2 ps (Figs. 42, 159)......................................................... 5
5. Mala without mbs (Fig. 35). Abdominal segment VIII with 1 ps (Fig. 43)................................. T. alpinus
- Mala with 1 mbs (Fig. 152). Abdominal segment VIII with 2 ps (Fig. 160)............................ .. T. curtirostris
6. Meso- and metathorax without as (Fig. 145). Abdominal segment VIII without ss (Fig. 147).............. T. breviusculus
- Meso- and metathorax with 1 as (Figs. 184, 197). Abdominal segment VIII with 1–2 ss (Figs. 186, 199)................ 7
7. Abdominal segments I–VII without prs and 2 ss (Fig. 185)............................................. T. meliloti
- Abdominal segments I–VII with 1 prs and 1 ss (Fig. 198).............................................. T. pusillus
8. Abdominal segments I–VII with 2 prs (Figs. 29, 94)......................................................... 9
- Abdominal segments I–VII with 1 prs (Figs. 9, 19, 55, 68, 81, 107, 120, 133).................................... 10
9. Pronotum with 6 prn (Fig. 28). Meso- and metathorax without as and ss (Fig. 28)................... T. quinquepunctatus
- Pronotum with 8 prn (Fig. 93). Meso- and metathorax with 1 as and 2 ss (Fig. 93)........................ T. capucinus
10. Meso- and metathorax with 2 prs (Fig. 80)........................................................ T. schneideri
- Meso- and metathorax with 1 prs (Figs. 8, 18, 54, 67, 106, 119, 132)........................................... 11
11. Abdominal segments I–VII with 1 pds (Fig. 107).................................................... T. caldarai
- Abdominal segments I–VII with 2 or 3 pds (Figs. 9, 19, 55, 68, 120, 133)....................................... 12
12. Abdominal segments I–VII with 2 pds (Figs. 68, 120)....................................................... 13
- Abdominal segments I–VII with 3 pds (Figs. 9, 19, 55, 133).................................................. 14
13. Abdominal segment VIII with 1 prs and 1 pds (Fig. 69)............................................. T. depressus
- Abdominal segment VIII without prs and with 2 pds (Fig. 121)..................................... T. squamulatus
14. Abdominal segment VIII without prs (Fig. 134)................................................... T. argentatus
- Abdominal segment VIII with 1 prs (Figs. 10, 20, 56)....................................................... 15
15. Abdominal segments I–VII with 1 ss (Fig. 9). Abdominal segment VIII with 3 pds (Fig. 10)................ T. parallelus
- Abdominal segments I–VII with 2 ss (Figs. 19, 55). Abdominal segment VIII with 1–2 pds (Figs. 20, 56).............. 16
16. Clypeus with 2 cls (Fig. 15). Abdominal segment X with 3 setae (Fig. 20)................................ T. striatulus
- Clypeus without cls (Fig. 51). Abdominal segment X with 1 seta (Fig. 56)................................. T. brisouti
Pupae
1. Femora without fes (Figs. 45, 84, 188, 201)................................................................ 2 - Femora with 1 or 2 fes (Figs. 32, 58, 71, 97, 110, 123, 136, 149, 162, 175, 214).................................... 5
2. Pronotum with 1 ds (Figs. 188, 189, 201, 202).............................................................. 3
- Pronotum with 2 ds (Figs. 45, 46, 84, 85).................................................................. 4
3. Rostrum with 1 rs (Figs. 200, 202). Meso- and metathorax with 2 setae (Fig. 201).......................... T. pusillus
- Rostrum without rs (Figs. 187, 189). Meso- and metathorax with 1 seta (Fig. 188).......................... T. meliloti
4. Rostrum without rs, head with 1 vs (Figs. 44, 46).................................................... T. alpinus
- Rostrum with 1 rs, head with 2 vs (Figs. 83, 85)................................................... T. schneideri
5. Pronotum with 1 ds and 1 pls (Figs. 71, 72, 123, 124, 162, 163, 175, 176, 214, 215)................................ 6
- Pronotum with 2 ds and 1 pls (Figs. 32, 33, 58, 59, 97, 98, 110, 111, 136, 137, 149, 150)........................... 10
6. Pronotum with 1 ls (Figs. 71, 72)............................................................... T. depressus
- Pronotum with 2 ls (Figs. 123, 124, 162, 163, 175, 176, 214, 215).............................................. 7
7. Meso- and metathorax with 2 setae (Fig. 214)........................................................ T. tibialis
- Meso- and metathorax with 1 seta (Figs. 123, 162, 175)....................................................... 8
8. Head with 2 os (Figs 122, 124)............................................................... T. squamulatus
- Head with 1 os (Figs 161, 163, 174, 176).................................................................. 9
9. Rostrum without rs (Figs. 174, 176).............................................................. T. decretus
- Rostrum with 1 rs (Figs. 161, 163)............................................................ .. T. curtirostris
10. Femora with 2 fes (Figs. 32, 136)....................................................................... 11
- Femora with 1 fes (Figs 58, 97, 110, 149)................................................................. 12
11. Head with 2 vs and without sos (Figs. 135, 137)................................................... T. argentatus
- Head with 1 vs and 1 sos (Figs. 31, 33).................................................... T. quinquepunctatus
12. Head with 2 vs (Figs. 57, 59).................................................................... T. brisouti
- Head with 1 vs (Figs 96, 98, 109, 111, 148, 150)........................................................... 13
13. Head with 2 os (Figs 96, 98).................................................................. T. capucinus
- Head with 1 os (Figs 109, 111, 148, 150)................................................................. 14
14. Rostrum without rs (Figs. 148, 150)........................................................... T. breviusculus
- Rostrum with 1 rs (Figs. 109, 111)................................................................ T. caldarai
description: Published as part of 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, pp. 1-83 in Zootaxa 3839 (1) on pages 25-27, DOI: 10.11646/zootaxa.3839.1.1, http://zenodo.org/record/4927721