Orchestina sakhalinensis Marusik, Perkovsky et Eskov, 2018

Marusik, Yu. M., Perkovsky, E. E. & Eskov, K. Yu., 2018, First records of spiders (Arachnida: Aranei) from Sakhalinian amber with description of a new species of the genus Orchestina Simon, 1890, Far Eastern Entomologist 367, pp. 1-9 : 4-6

Orchestina sakhalinensis Marusik, Perkovsky et Eskov , sp. n.

Figs 1–9

TYPE MATERIAL. Holotype ♂ ( PIN 3387 /731) and paratype ♀ ( PIN 3387 /

732), Russia: Starodubskoye, Sakhalinian amber, Middle Eocene. Well-preserved inclusion in clear yellow amber; syninclusions absent; both are deposited in PIN.

DIAGNOSIS. The new species resembles Orchestina imperialis Petrunkevitch,

1963 (cf. fig. 19 in Marusik & Wunderlich, 2008), a species known from Baltic amber. Two species have moderately swollen palpal tibia (not strongly as in many other species), relatively large cymbium and elongate patella. The new species differs by embolus bent anteriorly (vs. posteriorly), and not modified (swollen) palpal femur vs. thick femur. Two species differ also be length of embolus shorter in O.

sakhalinensis sp. n. (long and thin, stylus or whip like in O. imperialis ), but it can be caused of deformation of embolus and actually broken tip in the new species.

DESCRIPTION. Male (holotype, Figs 1–2, 6–9 ). Body 0.93 mm long. Carapace

0.36 mm long, 0.26 mm wide; slightly deformed; eyes not properly visible. Leg length: I 1.27 (0.39, 0.36, 0.31, 0.21), II 1.13 (0.4, 0.31, 0.23, 0.19). Femur IV 0.1

mm thick. Carapace, abdomen and legs covered with long setae.

Palp as in Figs 1–2 , 8–9 ; femur almost 2 times longer than patella; patella 1.5

shorter than tibia; tibia swollen, almost t time longer than wide cymbium slightly shorter than tibia; bulb massive; tegular part wider than patella, 2 times wider than long; psembolus long, as long as tegulum wide, tip of psembolus broken in both palps and real length of psembolus unknown as well as conformation of the tip, that can be stylus like or bifurcated.

Female (paratype, Figs 3–5 ). Total length са. 0.92 mm. Carapace 0.33 mm long.

Abdomen, carapace and legs covered with long hairs. Fe I-III ca 0.29 mm, patella+

tibia I 0.23 mm, metatarsus and tarsus I ca 0.17 mm. Tarsi I and II gradually widening toward the top, possibly due to the deformation. Femur IV not so wide as in male.

NOTES. The female considered as conspecific with the male because it has almost the same size and body covered with long hairs. At the same time, it has shorter legs with widened tarsi I and II, as well as no so strongly swollen femur IV.

Shape of the male palp does not fit to any of recognized species groups in fossil

Orchestina (sensu lato). Unlike in all other Orchestininae embolic part of the bulb

(psembolus sensu Saaristo, 2006) is bent anteriorly ("upward"), but not posteriorly

("downward"). Shape of the palp of new species does not resemble any extant species.

With some extent palp is little bit similar to these in O. chaparrita Izquierdo, 2017

( Mexico) and O. laselva Izquierdo, 2017 ( Costa Rica & Ecuador) (see Izquierdo &

Ramírez, 2017: figs 42a-b, g-h). These species have relatively small and not strongly swollen palpal tibia, long femur, large tegular part (wider than long), and elongate and almost straight psembolus with slightly bent tip in O. laselva . Both species have modified tip with lamellar structures unrecognizable in O. sakhalinensis sp. n.

due to deformed terminal part of psembolus.

ETYMOLOGY. The species name derived from the Sakhalin Island.

(3–5). 1 – prosoma ventral; 2 – habitus, dorsal; 3 – habitus, ventral; 4 – abdomen, dorsal; 5 –

habitus, lateral; 6–7 – tarsi I and II showing onychium.

habitus, dorsal; 9 – palp.

Figures

Figs 1–7. Orchestina sakhalinensis sp. n.: holotype male (1–2, 6–7) and paratype female

Figs 8–9. Line drawings of the holotype male of Orchestina sakhalinensis sp. n. 8 –