Kalliste pavonum, Martens, 2018

Martens, Jochen, 2018, A European discovery: Kalliste pavonum gen. nov., sp. nov., the smallest phalangiid species known to date (Arachnida: Opiliones: Phalangiidae), Revue suisse de Zoologie 125 (1), pp. 155-164 : 156-159

Kalliste pavonum sp. nov.

Figs 1-27

Holotype: SMF; male; France, Corsica, Département Haute-Corse , Col de Verde, 1200 m; J. and B. Martens; leg. 26.8.2012.

Paratypes: CJM 3373 ; 2 males; France, Corsica, Département Haute-Corse , Col de Verde, 42°01’N, 9°11’E, 1280 m; B. Schröter [later B. Pfau] & K. Pfau; leg. 9.1982 . – CJM 7255 ; 1 female; France, Corsica, Département Haute-Corse , Col de Vizzavona, 42°06’N, 9°06’E, 1000-1200 m; J. and B. Martens; leg. 8.9.2012 . – MHNG; 1 male; France, Corsica, Département Haute-Corse, Col de Vizzavona, 42°06’N, 9°06’E, 1000- 1200 m; J. and B. Martens; leg. 8.9.2012 . – CJM 7267 ; 1 female; France, Corsica, Col de Verde , 1200 m; J. and B. Martens; leg. 26.8.2012 .

Additional non-type material examined: CJM 7780 ; 2 juveniles; France, Corsica, Col de Vizzavona , 1000-1200 m; J. and B. Martens; leg. 29.8.2012 and 11.9.2012 . – CJM 7781 ; 1 juvenile; France, Corsica, Col de Verde , 1200 m; J. and B. Martens; leg. 26.8.2012 .

Diagnosis: At present, the diagnosis of genus Kalliste gen. nov. applies.

Remarks: It is noteworthy that Kalliste pavonum sp. nov. represents the smallest phalangiid species known to date. Tsurusaki (2007) mentions 2.2 mm as the minimum size for species of this family; K. pavonum sp. nov. is below that limit (see Measurements).

Name: Kalliste pavonum sp. nov. honors Beate and Klaus Pfau, distinctive zoologists who first provided specimens of this unusual species and put the material at my disposal. Pfau in Latin is “pavo”, peafowl in English, “pavonum” is the plural genitive case referring to both collectors.

Description: MALE: Body, dorsal side ( Figs 1 , 5-6 ): Small, roundish, dorsal side without marked armament of granules, “hooks” or strong setae; only on 2nd thoracal segment with a loose row of low denticles (and a few setae), latero-distal and lateral rim of prosoma with small spiny protuberances.

Colour pattern ( Figs 1 , 6 ): Fully grown adults with shiny silvery ground colour and marked saddle pattern extending over dorsal thoracal segments and opisthosoma, broadest on metapeltidium, narrowest on opithosomal segment I, from there broadening to rear rim of segment II, then irregularly tapering toward segments III, IV and V of opisthosoma, causing a brownish appearance. Irregular rows of few light spots of different sizes across metapeltidium and opisthosomal segments, ocularium light silvery, large eyes black.

Tuber oculorum ( Figs 1 , 5-6, 9 ): Large (in comparison with other phalangiids), shiny, situated near posterior edge of prosoma, set back from anterior end of prosoma by about half of its length, dorso-laterally armed with two irregular rows of about 10-12 stout denticles, each one carrying a short seta.

Body, ventral side ( Fig. 2 ): Cx with minute dark distal spot, otherwise like Op gen whitish with a yellow touch; free opisthosomal segments laterally light brown, medially with an irregular white stripe. Body unarmed except for few dark setae scattered on Cx and Op gen, shorter and hardly recognizable setae on opisthosomal segments.

Legs: Generally light to translucent, with broad, light brown, ring-shaped markings on Fe, Pt, Ti and Mt; size normal (in comparison with other phalangiids), with five sharply delimited longitudinal rows of minute, black, closely spaced setae accentuating the pentagonal cross section of Pt and Ti, less so of Fe; Mt and Ta with a rounded cross section; longest setae on tarsal articles; no denticles present on legs.

Pedipalp ( Figs 10-12, 16 ): Translucent shiny, raptorialclamp-type (by combination of both pedipalps) with strong equipment of Apo on Pt and Ti, massive spines on Fe and Ti ventrally, sexually dimorphic (see below). All articles stout and massive; Tr with few denticles and setae ventrally. Fe slightly bent ventrad, strong setae dorsally, pro-laterally and ventrally, on ventral side setae placed on blunt spines proximally and distally; a field of hairs (setae or microtrichia) present pro-laterally near distal end of Fe, at same position as knob-like Apo of female (see below). Pt large, with a prominent, pointed prolateral Apo directed slightly dorsad and distad, covered with strong setae; minute strong setae forming a curved field distally on pro-lateral side of Fe. Ti strong, slightly curved downwards, distinct knob-like pro-lateral Apo at distal end of article covered with few strong setae, longer setae present on dorsal and ventral side of Ti. Ta slender, curved ventrad, most slender in mid-part, tapering distally and proximally, covered all round with setae of different lengths, long and fine setae at distal end around the claw, minute trichomes interspersed. No ventral row (or band) of dark, sclerotized, point-like structures (as present in many species of various Phalangiinae genera). Claw ( Fig. 16 ) well developed, on inner (ventral) side two fine, filiform denticles with a slightly broadened base (not a comb-like row of denticles like in Sclerosomatidae or Dentizacheus Rambla, 1956 ), situated in proximal half.

Chelicera ( Fig. 7 ): Stout, 1st article short, with few denticles dorsally, 2nd article comparatively large, with several strong denticles at the proximal knee and on pro-lateral side, scattered setae frontally, pro- and retrolaterally; setae largest close to insertion of movable finger.

Penis morphology ( Figs 18-26 ): Truncus penis ( Figs 18-22 ) stout, enlarged base (in do/ve views) comprising about three fifth of whole truncus and containing penial muscle. Truncus from its base towards glans first slightly broadened for a short section, then slightly tapering and continuing more or less parallel-sided and slightly widening towards glans (in ve/do views). Base in la view ( Figs 20, 22 ) much slenderer, less abruptly merging into distal part of truncus. Glans ( Figs 23-24 ): In la view upper edge (i.e. ventral side) slightly concave, lower edge strongly bulging; two pairs of short setae in distal third of glans; in ve view strongly constricted at about mid-length. Stylus ( Figs 25-26 ) strong and relatively long, with a broad triangular tooth sub-distally on lower (i.e. dorsal) side.

FEMALE ( Figs 3-4 , 8 , 13-15, 17 , 27 ): Similar to male, Tu oc situated even closer to prosoma frontal rim, shiny and armed as in male.

Coloration and dorsal saddle markings: As in male, segments VI and VII silvery white, ventral side as in male, ovipositor visible through translucent cuticle of Op gen.

Chelicera ( Fig. 8 ): Proportions as in male, no denticles on 2nd article.

Pedipalp ( Figs 13-15, 17 ): Similar to male but with spines, setae and Apo more strongly developed (i.e. the normal phalangiid condition). Fe with long setae and several strong tubercles topped by a seta each spread all over ventral side, distally on pro-lateral side a knob-like Apo covered with few strong setae. Pt with Apo like in male but more pronounced, distally slightly rounded. Ti massive, ventrally with four spines of different sizes topped by a long seta each, pro-laterally at distal end a large knob-like Apo covering nearly entire depth of article (in pro-lateral view, Fig. 13 ), long setae mainly in distal part of article. Ta being the longest article, straight, slightly tapering towards distal end, covered by long setae all over, longest setae nearly reaching depth of article (in la view), in addition a dense coat of microtrichia. Claw ( Fig. 17 ) generally similar to that of male, lower (concave) side with two small denticles, each carrying a filiform apex, about twice as long as base, located in proximal half of claw.

Legs: Proportions similar to those of male; slightly less strong, black, closely spaced setae present; Pt less pentagonal but more rounded in cross section.

Ovipositor morphology ( Fig. 27 ): Two complete distal segment rings broader than proximal ones, three distal rings more or less distinctly split (last one completely split, second last one split only distally, third last one completely split). Long setae on two distal rings, shorter ones on proximal rings. Rec sem not recognizable. Distolateral bulbs on last segment longish, distally covered by long fine setae forming a compound sensillum ( Hoheisel & Martens, 1990).

Measurements: Body length of males 1.8-2.0 (n=4), of females: 1.9-2.6 (n=3). Leg II length of male (holotype), in parantheses of female paratype: Fe 2.7 (2.2), Pt 0.7 (0.6), Ti 2.3 (2.0), Mt 1.9 (1.4), Ta 5.3 (4.3). Pedipalp length of male, in parentheses of female: Tr 0.25 (0.25) Fe 0.6 (0.6), Pt 0.35 (0.4), Ti 0.4 (0.4), Ta 0.6 (0.8). Penis length of holotype and of one male paratype (n=2): 0.9, 1.0.

Variation: Shape of glans and length of stylus of glans vary remarkably ( Figs 23-26 ). Due to sparse material, detailed information is presently not available.

Distribution, habitat and phenology: According to present knowledge, K. pavonum sp. nov. is confined to the central mountainous parts of the island of Corsica ( France) and until now only known from two high-altitude passes, Col de Verde and Col de Vizzavona. These are in easy reach by car on good roads, about 35 km east of Aléria on the eastern coast. The two localities are separated from each other by approximately 12 km linear distance.

The specimens were found on the ground, under stones and dead wood, in forests dominated by beech ( Fagus sylvatica ). Present records lie between 1000-1200 m. Maturity time is August and September and may extend at least to the onset of frost; juveniles were also collected in August and September (see Material). Because of its small size and light colour, specimens of this species are easily overlooked among juveniles of other species to which adults of K. pavonum sp. nov. look similar.

Figures

Figs 1-4. Kalliste pavonum gen. sp. nov. (1) Body of male holotype in dorsal view. (2) Same in ventral view. (3) Body of female paratype in dorsal view. (4) Same in ventral view. Scale: 0.5 mm.

Figs 5-9. Kalliste pavonum gen. sp. nov. (5) Body of male holotype with chelicerae and pedipalps in lateral view. (6) Same (without chelicerae and pedipalps) in dorsal view. (7) Male chelicera in retro-lateral view. (8) Female chelicera in same view. (9) Male tuber oculorum in lateral view. Scales: 1.0 mm (Figs 5-6); 0.3 mm (Figs 7-8); 0.25 mm (Fig. 9).

Figs 10-17. Kalliste pavonum gen. sp. nov. (10-12) Male pedipalp in pro-lateral (10), retro-lateral (11) and dorsal view (12); patella and tibia only (11-12). (13-15) Female pedipalp in pro-lateral (13), retro-lateral (14) and dorsal view (15); patella and tibia only (14-15). (16-17) Palpal claws of male (16) and female (17), both from Col de Verde, lateral view. Scales: 0.3 mm (Figs 10-15); 0.03 mm (Figs 16-17).

Figs 18-27. Kalliste pavonum gen. sp. nov. Male and female copulatory organs. (18-20) Penis of male from Col de Verde in ventral (18), dorsal (19) and lateral view (20). (21-22) Penis of male from Col de Vizzavona in dorsal (21) and lateral view (22). (23-24) Stylus, glans and distal part of truncus penis in lateral view (23: Col de Verde, 24: Col de Vizzavona). (25-26) Distal part of stylus in lateral view (25: Col de Verde, 26: Col de Vizzavona). (27) Distal part of ovipositor in ventral view. Scales: 0.3 mm (Figs 18-22); 0.05 mm (Figs 23-24); 0.025 mm (Figs 25-26); 0.2 mm (Fig. 27).