Caracladus avicula L. Koch 1869
Creators: name: Frick, Holger
name: Muff, Patrick
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Linyphiidae
Caracladus
Caracladus avicula

description: Caracladus avicula (L. Koch, 1869)
(Figs 1–28)
Erigone avicula L. Koch, 1869: 30.
Caracladus aviculus, Simon 1884: 590, figs 408–409; Simon 1894: 658, fig. 657; Simon 1926: 387, 498, fig. 690. Caracladus avicula, Thaler 1969: 205, figs 15–21; Thaler 1972: 32, figs 7–11; Millidge 1977: 40, fig. 162; Heimer and Nentwig 1991: 124, fig. 350.1–350.5; Pesarini 1996: 416, figs 9–10.
Type material. HOLOTYPE: Austria: Tyrol: Küthai, next to the chapel, ca. 1950 m [47°12'45'' N, 11°00'50'' E], ♂ 08.vii, under a stone, leg. A. Ausserer (Koch 1869). Koch (1869) notes that Anton Ausserer found both sexes together. The whereabout of the material is not known to the authors. Parts of the collection of Ludwig Koch are stored in the BMNH (Horn et al. 1990), but the material from Küthai was untraceable. Instead, there is one tube with two intact males and one tube with several legs, one abdomen, two right and two left palps in the collections of the BMNH. They are tagged as “coll. Koch” but with notes saying “E. Simon” and “Hautes- Alpes”. As Simon (e.g. 1884) usually used the term “Hautes-Alpes” for a province in France, these specimens most probably are not Koch’s original types.
Examined material. Austria: Carinthia: Grossglocknerstrasse, Guttal, 1900–1960 m [47°03'40'' N, 12°47'15'' E], 10♂ 9♀ 29.vi.1978 – 15.ix.1979, meadow and edge of larch forest with stones and dwarf-shrub heath (Rhododendron), leg. K. Thaler (MHNG) (Thaler 1989). Tyrol: Innsbruck, Patscherkofel, 2000 m [47°12' N, 11°27' E], 10♂ 4♀ 1997, leg. Ebenbichler (NHMW 1999 XVIII) (Rief et al. 2001); Stubaital, above Schönberg, Gleinser Jöchl, 1600 m [47°08'47'' N, 11°24'31'' E], 1♂ 19.viii.1962, leg. and coll. K. Thaler (Thaler 1969); Stubaier Alpen, Maria Waldrast, ca. 1650 m [47°07'54'' N, 11°24'27'' E], 18♂ 1♀ 22.iv.–15.v.1976, 2♂ 15.v.–06.vi.1976, 1♂ 3♀ 06.iv–26.vi.1976, 6♀ 26.vi.–28.vii.1976, 3♂ 4♀ 28.vii.–29.viii.1976, 1♀ 29.viii.–02.x.1976, 4♂ 1♀ 16.xi.1976 – 04.v.1977, subalpine spruce forest, leg. and coll. K. Thaler (Thaler 1982). Vorarlberg: Montafon, Garneratal, close to Tübinger Hütte, 2040 m [46°54'43'' N, 9°59'58'' E], 1♂ 10.ix.1998 – 27.vii.1999, 1♂ 31.viii.1999 – 19.vii.2000, 1♂ 29.viii.2000 – 19.vii.2001, leg. and coll. W. Breuss (Breuss unpubl.). France: Provence-Alpes-Côte d'Azur: Hautes-Alpes, le Monétier, lower border of forest, ca. 1400 m [44°58'30'' N, 6°30'30'' E], 4♂ viii, leg. E. Simon (BMNH) (Cambridge 1875; Simon 1884). Rhône-Alpes: Haute-Savoie, Col de Mont Cenis, 1700 m [45°16' N, 6°54' E], 2♂ 6.vi.1986, pitfall trap in larch forest, leg. and coll. R. Bosmans (Bosmans unpubl.). Germany: Bavaria: Allgäu, Einödsberg, close to Einödsbach, 15 km south of Oberstdorf, ca. 1900 m [47°19'41'' N, 10°17'20'' E], 1♂ 20.vi.2004, coll. C. Muster (Muster pers. com.); Allgäuer Alpen, Ponten, 1450 m – 1920 m [47°29' N, 10°27' E], 17 adults vi–v, subalpine spruce forest, leg. C. Muster (Muster 2001); Ammergebirge, Hochplatte, 1450–1920 m [47°33' N, 10°50' E], 22 adults vi–v, subalpine spruce forest, meadow, alpine meadow, leg. C. Muster (Muster 2001); Garmisch-Patenkirchen, 7 km northwest of G.-P., 1700 m [47°31'9'' N, 11°0'33'' E], 7♂ 09.viii.–13.ix.1990, northern slope of Krottenköpfel, leg. G. Schmidt, coll. T. Blick (Schmidt 1994). Italy: Trentino: Monte Coppolo, Dolomites, 1900 m [46°05'33'' N, 11°42'17'' E], 1♂ 1♀ 12.ix.–20.x.1999, 2♂ 2♀ 20.x.–28.vi.1999, alpine meadow, leg. V. Zingerle (NB) (Zingerle 1999a); Sextner Dolomiten, national park, 2000 m [46°41'19'' N, 12°19'38'' E], 4♀ 22.vi.–24.vii.1997, 1♂ 5♀ 21.v.–22.vi.1997, 1♂ 1♀ 24.vii.–22.viii.1997, 6♂ 1♀ 21.x.1997 – 02.vi.1998, mountain meadow, leg. V. Zingerle (NB) (Zingerle 1999b); Sextner Dolomiten, national park, 1960 m [46°41'24'' N, 12°19'26'' E], 5♀ 22.vi.–24.vii.1997, 5♀ 21.v.–22.vi.1997, 3♂ 1♀ 22.viii.–21.ix.1997, 16♂ 7♀ 21.x.1997 – 02.vi.1998, meadow with many trees, leg. V. Zingerle (NB) (Zingerle 1999b); Naturpark Puez-Geisler, Dolomites, 2♂ 1♀ 1995/1996, leg. V. Zingerle (NHMW 1997 IX); Naturpark Puez-Geisler, Dolomites, 1500 m [46°37'34'' N, 11°51'14'' E], 17♂ 4♀ 12.i.–21.iv.1995, 20♂ 1♀ 11.iv.–30.iv.1995, 11♂ 3♀ 30.iv.–21.v.1995, 1♂ 5♀ 21.v.–18.vi.1995, 1♀ 18.vi.–09.vii.1995, 4♀ 29.vii.–20.viii.1995, 2♂ 20.viii.–09.ix.1995, 1♀ 09.ix.–30.ix.1995, meadow with many trees and light larch-spruce forest, leg. V. Zingerle (NB) (Zingerle 1999a); Naturpark Puez-Geisler, Dolomites, 1490 m [46°38'11'' N, 11°51'43'' E], 1♂ 12.i.–21.iv.1995, 1♂ 21.v.–18.vi.1995, larch-spruce forest, leg. V. Zingerle (NB) (Zingerle 1999a); Naturpark Puez-Geisler, Dolomites, 2100 m [46°36'27'' N, 11°50'42'' E], 1♀ 18.vi.1995 – 9.vii.1995, meadow at alpine timberline, leg. V. Zingerle (NB) (Zingerle 1999a); Rolle Pass, 1920 m [46°18'39'' N, 11°49'17'' E], 1♂ 1♀ 27.viii.–23.ix.1997, 2♂ 1♀ 24.x.1997 – 03.v.1998, larch-spruce forest, blockforest, leg. V. Zingerle (NB) (Zingerle 1999a). Ven e ti a: Valparola-Pass, Dolomites, 2160 m [46°31'67'' N, 11°59'60'' E], 1♂ 1♀ 13.xi.1998 – 16.vi.1999, meadow at alpine timberline, leg. V. Zingerle (NB) (Zingerle 2000a); Valparola-Pass, Dolomites, 2130 m [46°31'31'' N, 11°00'25'' E], 1♂ 13.vi.–15.vii.1998, light dwarf pine area, leg. V. Zingerle (NB) (Zingerle 2000a). Switzerland: Bern: Gadmen, Gadmertal, Schaftelen, 1200 m – 1600 m [46°43'16'' N, 8°19'30'' E], 1♀ 06.viii.1932, forest floor, leg. E. Schenkel (NMB 810g) (Schenkel, unpubl.). Grisons: Alp Tavrü, ca. 2100 m [46°42'00'' N, 10°18'28'' E], 1♂ viii., leg. R. de Lessert (MHNG) (Lessert unpubl.); Davos, ca. 1600 m [46°48' N, 9°50' E], 1♂ 03.v.–06.vi.1979, leg. Wartmann (NMB 810m) (Wartmann unpubl.); Dischmatal, ca. 1700 m – 2100 m [46°45'10'' N, 9°54'00'' E], 1♀ 07.ii.–28.vi.1979, leg. Wartmann (NMB 810l) (Wartmann unpubl.); Unterengadin, Ramosch, ca. 1150 m [46°50'00'' N, 10°22'50'' E], 6♂ 2♀ 06.xii.1970 – 19.vi.1971, leg. and coll. K. Thaler (Thaler 1972); St. Moritz, 1800 m [46°29'40'' N, 9°50'10'' E], 1♂ 1916, leg. P. Revilliod (NMB 810b) (Revilliod unpubl.); Sur, Alp Flix, Salategnas, 1960 m [46°31'07'' N, 9°38'48'' E], 51♂ 54♀ 15.v.–14.vi.2003, 26♀ 14.vi.–07.vii.2003, 5♂ 18♀ 07.vii.–04.viii.2003, 11♂ 12♀ 04.viii.–03.ix.2003, 9♂ 18♀ 03.–28.ix.2003, 11♂ 19♀ 28.ix.–28.x.2003, 164♂ 72♀ 28.x.2003 – 24.v.2004, alpine timberline, leg. H. Frick (NMBE) (Frick et al. 2006); Sur, Alp Flix, Salategnas, 1960 m [46°31'07'' N, 9°38'48'' E], 1♀ 20.–27.vi.2002, 1♀ 27.vi.–04.vii.2002, 2♀ 04.–11.vii.2002, 3♀ 11.–18.vii.2002, 3♀ 18.–25.vii.2002, 2♂ 25.vii.–01.viii.2002, 1♀ 08.–15.viii.2002, 1♀ 15.–26.viii.2002, 1♂ 26.viii.–11.ix.2002, 1♂ 11.ix.–01.x.2002, 13♂ 2♀ 01.x.2002 – 14.v.2003, 3♀ 14.–29.v.2003, 1♀ 14.v.–09.vi.2003, 1♀ 29.v.–09.vi.2003, alpine timberline, leg. A. Bolzern, A. Hänggi (NMB) (Frick et al. 2006); Sur, Alp Flix, Salategnas, 1960 m [46°31'05'' N, 9°38'47'' E], 16♂ 33♀ 27.v.–24.vi.2005, 1♂ 39♀ 25.vi.–23.vii.2005, 2♂ 10♀ 24.vii.–21.viii.2005, 10♂ 15♀ 22.viii.–18.ix.2005, 8♂ 11♀ 19.ix.–16.x.2005, 28♂ 17♀ 17.x.2005 – 06.v.2006, alpine timberline, leg. P. Muff (NMBE) (Muff et al. 2007). Ticino: Olivone, Campra di La, 1425 m [46°31'12.58'' N, 8°52'07.40'' E], 1♂ 02.viii.1992, raised moss, leg. F. Rampazzi (NMB 810k) (Rampazzi unpubl.); Val Bedretto, Bedretto to Alpe di Folcra, 1400m- 1800m [46°30'8'' N, 8°30'59'' E], 1♀ 11.–22.vii.1927 /1928, forest slope on the right valley side, leg. E. Schenkel (NMB 810e) (Schenkel 1929). Valais: close to Fiesch, Rafgarten – Ober Titer, 1500–1600 m [46°30'50'' N, 8°18'20'' E], 3♂ 6♀ 15.vii.1925, leg. E. Schenkel (NMB 810c) (Schenkel 1926); Leukerbad, ca. 1400 m [46°22'30'' N, 7°37'30'' E], 2♀ viii.1930, leg. R. de Lessert (NMB 810h) (Lessert unpubl.); Lötschental, close to Ried, 1500–1600 m [46°24'50'' N, 7°48'20'' E], 3♂ 16♀ vii.1938, leg. E. Schenkel (NMB 810i) (Schenkel 1939); Saas-Tal, Saas- Tal below Saas-Fee, Almagell-Saas-Fee [46°6'30'' N, 7°55'40'' E], 1♂ 15♀ vii.,viii., E. Schenkel (NMB 810d) (Schenkel); Zermatt,> 1600 m [46°1' N, 7°44' E], leg. and coll. K. Thaler (Thaler 1972).
Unexamined literature records. Austria: Tyrol: Lech, Forchach, ca. 900 m [47°25'48'' N, 10°35'26'' E], Blockau, (Steinberger 1996); Obergurgl, 1960 m [46°52'' N, 11°02' E], 5♂ 2♀ 02.ix.1976 – 08.x.1976, hey meadow, leg. S. Puntscher (Puntscher 1980). Germany: Bavaria: Mangfallgebirge, Hochmiesing, Alp Spitze, Hoher Fricken, ca. 1500–1700 m [47°39' N, 11°57' E] (Staudt 2008). Italy: Aosta valley: La Thuile, 1800 m [45°42'53'' N, 6°56'56'' E], 2♀, leg. Focarile (MSNM) (Pesarini 1996). Lombardia: Presolana [45°53' N, 10°03' E], 1♂ 23.vii.1989, leg. Sciaky (MSNM) (Pesarini 1996). Trentino: close to Corvara, 1700–1800 m [46°33'10'' N, 11°53'00'' E], 2♂ many ♀ vii.1973, Dolomites, leg. A. F. Millidge (Millidge 1979). Switzerland: Grisons: Engadin, Sils, Baselgia, ca. 1800 m [46°26'03'' N, 9°45'22'' E], leg. Kummer (Vogelsanger 1947); Frauenkirch, Aebiwald, 1600 m – 2000 m [46°45'39'' N, 9°48'58'' E], vi.–vii., subalpine zone, leg. T. Vogelsanger (Vogelsanger 1947); Pontresina, Belvoir, ca. 1850 m [46°29'30'' N, 9°54'20'' E], subalpine zone, leg. Kummer (Vogelsanger 1947); Trins, Flims, ca. 900–1200m [46°50' N, 9°19' E], vii, leg. E. Schenkel (Vogelsanger 1947). Valais: path to Saas-Fee [46°06'30'' N, 7°55'40'' E], 1♂ 12./ 18.vii.1929, forest zone, left valley slope, leg. E. Schenkel (Schenkel 1933); Saas-Fee, Egg or Bärenfalle or Fluh or Imseng or Bider, 1700–1900 m [46°07'30'' N, 7°55'40'' E], 4♂ 8♀ 07.viii.1926, leg. E. Schenkel (Schenkel 1927); Saas-Fee, Gletscheralp, around the hut, 2135 m [46°04'51'' N, 7°55'01'' E], 1♀ 05.viii.1926, leg. E. Schenkel (Schenkel 1927); Vassorey, close to Bourg-Saint-Pierre, lower border of forest, ca. 1633 m [45°56'50'' N, 7°12'30'' E], viii, leg. Simon (MNHN) (Simon 1884); Zermatt, äussere Wälder, ca. 2000 m [46°01' N, 7°44' E], 5♀, leg. T. Vogelsanger (Vogelsanger 1944).
Diagnosis. Males: Koch (1869) describes the cephalic lobe in detail as “similar to a bird head, placed on a long neck” which is indicated in the species epithet “ avicula ”. This lobe has been considered to be typical for C. avicula but is also present in C. zamoniensis spec. nov. However, C. avicula with long, straight, whip-like embolus that narrows constantly towards the end (Figs 18, 19). Cephalic lobe much thinner below the eyefield than above. Distance between channel-like sulcus and AME above 0.12 mm (Fig. 22).
Females: Dorsal plate rectangular without sclerotised parts visible in transparency through the dorsal plate but lateral to it (Fig. 26). Epigyne with two anterior pouches formed by the ventral and the dorsal plate (Fig. 26). They are much larger and less sclerotised than in C. zamoniensis spec. nov. (Fig. 56). Vulva with a rather complex copulatory duct (Figs 27, 28).
Description. Male (NMBE Ar 5292): Total length 2.02 mm. Cephalothorax: honey brown (138 U); reticulated; 0.84 mm long without cephalic lobe, 1.19 mm long with cephalic lobe, 0.71 mm wide. Cephalic lobe: light brown (124 U); Thaler (1969) describes this lobe as slim elongated shaft which is sloped forwardly, originating at the position of the median eyes (Fig. 23), with a hairy tip that is laterally compressed (Fig. 21); smallest diameter below the eye-field 0.06 mm wide laterally, 0.07 mm wide dorsally; ventral side of the shaft with channel-like depression bearing a sulcus (Thaler 1969), margin of sulcus 0.16 mm below the AME (Fig. 22). Eyes: PME dorsally on tip of lobe; AME projecting forward from the shaft (Fig. 23); one long macroseta projecting forward between AME (Fig. 23). Clypeus: directed obliquely backwards (Fig. 23). Sternum: very fine brown (469 U) pigmentation on yellow (124 U) ground, dark brown (469 U) on the margins; 0.47 mm long; 0.47 mm wide. Chelicerae: light brown (124 U); stridulatory striae fine and dense (Fig. 13); promargin with five big teeth; retromargin with five denticles. Legs: yellow (120 U); tibia I–IV with one dorsal proximal macroseta (1-1-1-1), 1.3–1.6 times longer than diameter of tibia; Tm I: 0.58 mm. Pedipalp: yellow (120 U); patella cylindrical; tibia nearly two times longer than broad, with glabrous band retrolaterally (Fig. 20), dorsal with highly sclerotised small tip facing forward (Fig. 20); paracymbium simple clasp (Fig. 17); tegulum distal with short and long papillae on protegulum (Figs 17, 18); suprategulum kneed; column broad; marginal suprategular apophysis present (Thaler 1969: Figs 17, 18); distal suprategular apophysis pointed (Thaler 1969: Figs 17, 18); embolic membrane slender; radix simple without any processes other than the short radical tailpiece and the strongly sclerotised, slim, terminal, whip-like embolus (Figs 18, 19). Abdomen: dorsal olive green to brown (125 U), ventral darker (117 U); booklung covers brown (125 U), scaly (Fig. 15).
Female (NMBE Ar 5315): Total length: 1.79 mm. Cephalothorax: honey brown (138 U); broad eggshaped (Thaler 1972); 0.77 mm long, 0.62 mm wide. Eyes: eye-field steep (Thaler 1972); posterior eyes separated by their diameter; AME separated by their radius. Clypeus: concave. Sternum: very fine brown (469 U) pigmentation on yellow (124 U) ground, dark brown (469 U) on the margins; 0.47 mm long; 0.47 mm wide. Legs: yellow (122 U); tibia I–IV with one dorsal proximal macroseta (1-1-1-1), 1.4–1.8 times longer than diameter of tibia; Tm I: 0.56. Chelicerae: light brown (124 U); promargin with five teeth; retromargin with five denticles; stridulatory striae indistinct and scaly. Epigyne: rectangular dorsal plate visible in ventral view; receptacula laterally to dorsal plate, visible in transparency trough ventral plate (Fig. 26). Vulva: copulatory pouch narrows in the middle of the vulva forming a copulatory duct (Figs 26, 27); receptacula globular, incoming dorsally. Abdomen: dark olive green to black (147 U). Tracheal system with two thick median and two thin lateral tracheae (Fig. 25).
Variation. The measurements are based on specimens from the NMBE (Ar5281, Ar5290, Ar5292, Ar5298, Ar5304, Ar5315, Ar5318, Ar5324, Ar5329, Ar5352, Ar5356: 6♂ 6♀) and the NB (P-G 1-4 H, P-G 1- 4 I, coll. Zingerle: 4♂ 3♀).
Males (n=10, means in brackets): The coloration is variable. Total length 1.95–2.31 mm (2.10 mm). Cephalothorax: 0.76–0.89 mm (0.82 mm) long without cephalic lobe, 1.10–1.26 mm (1.17 mm) long with cephalic lobe, 0.65–0.71 mm (0.69 mm) wide. Cephalic lobe: smallest diameter below the eye-field 0.06–0.07 mm (0.06 mm) wide laterally, 0.06–0.08 mm (0.07 mm) wide dorsally; margin of sulcus 0.12–0.16 mm (0.14 mm) below the AME. Legs: dorsal proximal macroseta on tibia 1.3–1.6 times longer than diameter of tibia (Thaler 1969); Tm I: 0.50–0.61 mm (0.56 mm).
Females (n=9, means in brackets): The colorations are variable. Total length: 1.68–1.91 mm (1.80 mm). Cephalothorax: 0.77–0.84 mm (0.81 mm) long, 0.62–0.67 mm (0.65 mm) wide. Legs: dorsal proximal macroseta on tibia 1.4–1.8 times longer than diameter of tibia; Tm I: 0.53–0.60 mm (0.57 mm).
Distribution. Endemic to the Alps, distributed between the Western- and the Eastern Alps (Thaler 1969) in France, Switzerland, Germany, Austria and Italy (Fig. 59). The records in Romania (Fuhn & Oltean 1970) are questionable (Thaler 1972). Bonnet (1956) erroneously lists C. avicula as present in Hungary citing Kolosváry (1939) who mentioned this species as a characteristic subalpine spider of Switzerland (Thaler 1972).
Habitat. Subalpine region, in moss of coniferous forests (Lessert 1910; Maurer & Hänggi 1990). Records between 1150–2160 m (Muster 2001) in litter of coniferous forests (mainly Norway spruce, Picea abies, sporadically mixed with larch, Larix decidua) (Zingerle 1999a). Extensive sampling at the alpine timberline at 1960 m a.s.l. showed that C. avicula occurs in the litter of subalpine Norway spruce forests and is also common under stand alone trees in the dwarf-shrub heath (Frick et al. 2006). However, it is more or less absent in the surrounding open areas like meadows and dwarf-shrub heath (Muff et al. 2007).
Phenology. Adults eurychronous in lower altitudes (Thaler 1972). However, alpine records (Zingerle 1999a; Frick et al. 2006; Muff et al. 2007; together sampled app. 80% of the collected specimens) indicate winter activity between September and April.
Remarks. Our discovery of two sympatric Caracladus species (the first with a male cephalic lobe that is wider above the eye-field (AME, ALE, PLE) than below and with a longitudinal channel-like sulcus, the second one with an equally broad “neck” above and below the eye-field with a transverse cup-like sulcus) leads to the question, which species L. Koch had described as C. avicula. From Koch’s (1869: 31) original description it is clear that the name C. avicula refers to the first species (“... über diesen Augen [AME, ALE, PLE] wird der Fortsatz dicker”; “...die Basis ... ist an der Unterseite rinnenartig ausgehöhlt, wo diese Rinne aufhört, sitzen die beiden vorderen Mittelaugen...”). The second species is here newly described. The original description of the female in Koch (1869) is ambiguous and was therefore redescribed in Thaler (1969).
Lessert (1907) noted that his specimens from Valais and Bern differ slightly from Simon’s (1884) drawings. According to Thaler (1972), Lessert’s (1907: Fig. 7; 1910: Fig. 100) females belong to Diplocentria bidentata (Emerton, 1882). Lessert’s (1907: Figs 5–6; 1910: Figs 98–99) males belong to C. zamoniensis spec. nov.
description: Published as part of Frick, Holger & Muff, Patrick, 2009, Revision of the genus Caracladus with the description of Caracladus zamoniensis spec. nov. (Araneae, Linyphiidae, Erigoninae), pp. 1-37 in Zootaxa 1982 on pages 7-13, DOI: 10.5281/zenodo.185321