Larinioides Caporiacco, 1934

Šestáková, Anna, Marusik, Yuri M. & Omelko, Mikhail M., 2014, A revision of the Holarctic genus Larinioides Caporiacco, 1934 (Araneae: Araneidae), Zootaxa 3894 (1), pp. 61-82 : 62-64

Larinioides Caporiacco, 1934

Type species: Larinioides dernae Caporiacco, 1934 [= L. folium ( Schrank, 1803) ( Grasshoff 1983) ].

History of Study: The genus was described as including only the type species, L. dernae Caporiacco, 1934 . Later, Caporiacco (1940) described another species, L. subinermis Caporiacco, 1940 from Ethiopia, which was recently transferred to Singafrotypa Benoit, 1962 ( Šestáková & Omelko 2012) . Larinioides included just two species until Grasshoff (1983) studied the type material and found that L. dernae was a junior synonym of Araneus folium . At that time all species currently included in Larinioides were placed in Nuctenea Simon, 1864 (cf. Levi 1974) or in Araneus (e.g. Palmgren 1974; Thaler 1974).

Diagnosis. Larinioides males differ from all other Holarctic araneid genera by having a one-armed (lacking median spur) median apophysis with bipartite tip ( Fig. 10 ) (not a bifurcated median spur as in Aculepeira ), a very simple and weakly sclerotized conductor ( Fig. 9 ), and a well-developed subterminal apophysis 2 ( Figs 11–24 , blue). The transparent protrusion on retrolateral side of embolus is unique among Palaearctic Araneidae ( Figs 11–25 ), except for Nuctenea Simon, 1864 . Another character shared by Larinioides and Nuctenea is the unmodified male tibiae on legs I and II. Females have a shorter flexible scapus and the median plate of the epigyne is not so protruding (except L. chabarovi ) with a raised, folded margin forming lateral lamellae ( Figs 26–32 ). The habitus of Larinioides is very similar to Nuctenea , especially in females of L. ixobolus , which can be confused with N. umbratica . However, unlike Nuctenea , males of Larinioides have long terminal apophysis and females (except L. patagiatus ) have a thin, flexible scapus. Both sexes of Larinioides have a typical brown folium , apically with white-bordered triangular macula.

The monophyly of Larinioides has not been tested phylogenetically and this is beyond the scope of this study. However, the genus does not appear to be paraphyletic and we are not altering the limits of this genus.

Description. Medium-sized, total length ♂♂ 5.5–9.5, ♀♀ 7.7–12. Coloration grey to brown ( Figs 1–7 ). Carapace uniformly coloured or with dark pattern, covered with pale hairs. Cephalic area protruding. Abdomen oval, dorsoventrally slightly flattened, without humps; dark folium always present, usually with large, pale, crosslike pattern with dark cardiac mark and anterior triangular macula. Ventrally between epigastrium and spinnerets with a dark median strip enclosed by white longitudinal wide bands. Legs yellow, annulated with dark rings ( Fig. 8 ).

Males. Coxa I with a hook and corresponding depression on base of femur II. Tibia II not modified, at least slightly shorter and thicker than tibia I ( Fig. 8 ). Palp heavily sclerotised. Patella with 2 macrosetae. Cymbium narrow. Radius well-developed. Stipes indistinct, and most probably fused with embolus. Median apophysis with one arm, relatively large and projecting, terminal tip bipartite ( Fig. 10 ). Conductor weakly sclerotized, simple with a widened distal end ( Fig. 9 ). Subterminal apophysis 1 rounded; subterminal apophysis 2 pointed or serrated ( Figs 11–24 , pink and blue). Terminal apophysis long and pointed, except in L. patagiatus and L. sericatus ; L. ixobolus have only a short pointed process ( Figs 11–24 , red). Embolus massive, terminally pointed, without cap, retrolaterally with semitransparent protrusion ( Figs 11–24 , green). There are two types of embolus ( Fig. 25 ). First type has a flat shield covering embolus tip ( L. cornutus , L. ixobolus , L. jalimovi , L. folium ). The second type lacks a shield, and embolus tip is clearly visible ( L. chabarovi , L. patagiatus , L. sericatus ).

Females. Epigyne well sclerotised, scapus flexible, narrow, originated anteriorly, except a large short pearshaped scapus in L. patagiatus and a strongly reduced scapus in L. chabarovi ; median plate edged by lateral lamellae; copulatory openings usually covered posteriorly by lateral lamellae. Three species with noticeable basal lamellae ( L. cornutus , L. ixobolus , L. folium ); in other species, basal lamella most probably fused with lateral lamellae ( Figs 26–32 ).

Composition. We include seven species in this genus: L. chabarovi (Bakhvalov, 1981) , L. cornutus ( Clerck, 1757) , L. folium ( Schrank, 1803) , L. ixobolus ( Thorell, 1873) , L. jalimovi (Bakhvalov, 1981) comb. n., L. patagiatus ( Clerck, 1757) , and L. sericatus ( Clerck, 1757) .

Natural history. The species of Larinioides build vertical orb-webs, often near water, on reeds, bridges, and fences. In extreme habitats without suitable vegetation it makes retreats among stones (e.g. L. jalimovi , this paper; L. cornutus, Braendegård 1958 ). Larinioides patagiatus sometime builds webs far from water on tree trunks. Retreats of Larinioides are usually covered by plants (e.g. L. folium , L. cornutus ), under bark, or in crevices (e.g. L. ixobolus , L. sericatus ). Males can mate three to four times with each palpus (Gerhardt 1926). They appear to clog up the copulatory openings of epigyne with an amorphous plug ( Figs 26 A, 27A, 32C), with the exception of L. patagiatus , where a broken scapus was often found ( Šestáková & Krumpál 2012; personal observation). Whether this damage is caused by male during copulation requires a further study.

Figures

FIGURE 8. Prolateral view of the second pair of male legs of Larinioides species. A— L. jalimovi; B— L ixobolus; C— L. sericatus; D— L. patagiatus; E— L. chabarovi, F— L. cornutus; G— L. folium.

FIGURE 9. Conductor of male palp of Larinioides species. A— L. jalimovi; B— L. ixobolus; C— L. sericatus; D— L. patagiatus; E— L. chabarovi; F— L. cornutus; G— L. folium.

FIGURE 10. Median apophysis of male palp of Larinioides species. A— L. jalimovi; B— L. ixobolus; C— L. sericatus, arrow pointed to the spur from different view; D— L. patagiatus; E— L. chabarovi; F— L. cornutus; G— L. folium.

FIGURE 25. Two types of embolus of Larinioides species. The first type (A, B) has a complex structure, the embolus tip (grey) is covered by a flat shield. The second type (C, D) lacks this shield and embolus is exposed. Arrows point to a transparent protrusion. Spermatic ducts are marked with dashed lines. A— L. ixobolus; B— L. folium; C— L. sericatus; D— L. patagiatus.

FIGURES 11, 12. Male embolic division of Larinioides jalimovi. Letters indicate columns; numbers indicate rows. 11 — before maceration; 12 — after maceration in NaOH solution; A, B—prolateral view; C, D—retrolateral view. TA = terminal apophysis; STA = subterminal apophysis; EM = embolus.

FIGURES 13 – 16. Male embolic division of Larinioides cornutus and L. folium. Letters indicate columns; numbers indicate rows. 13, 14 — L. cornutus; 15, 16 — L. folium; 13, 15 — before maceration; 14, 16 — after maceration in NaOH solution; A, B—prolateral view; C, D—retrolateral view.

FIGURES 17, 18. Male embolic division of Larinioides ixobolus. Letters indicate columns; numbers indicate rows. 17 — before maceration; 18 — after maceration in NaOH solution; A, B—prolateral view; C, D—retrolateral view.

FIGURES 19, 20. Male embolic division of Larinioides chabarovi. Letters indicate columns; numbers indicate rows. 19 — before maceration; 20 — after maceration in NaOH solution; A, B—prolateral view; C, D—retrolateral view.

FIGURES 21 – 24. Male embolic division of Larinioides sericatus and L. patagiatus. Letters indicate columns; numbers indicate rows. 21, 22 — L. sericatus; 23, 24 — L. patagiatus; 21, 23 — before maceration; 22, 24 — after maceration in NaOH solution; A, B—prolateral view; C, D—retrolateral view.

FIGURES 26 – 32. Epigyne of Larinioides species. Letters—columns. Numbers—rows. 26 — L. jalimovi; 27 — L. ixobolus; 28 — L. sericatus; 29 — L. patagiatus; 30 — L. cornutus; 31 — L. folium; 32 — L. chabarovi. A – D—posterior, E—lateral, F—dorsal view. A, C—before maceration; B, D – F—after maceration in NaOH solution. BL = basal lamella, LL = lateral lamella, SC = scapus.

FIGURES 1 – 4. Habitus of Larinioides species. Letters indicate columns; numbers indicate rows. 1 — L. jalimovi; 2 — L. ixobolus; 3 — L. sericatus; 4 — L. patagiatus. A, B—females; C, D—males; A, C—dorsal side; B, D—ventral side.

FIGURES 5 – 7. Habitus of Larinioides species. Letters indicate columns; numbers indicate rows. 5: L. chabarovi; 6: L. cornutus; 7: L. folium. A, B—females; C, D—males; A, C—dorsal side; B, D—ventral side.