Fourteen new species of the spider genus Thaiderces from Southeast Asia (Araneae, Psilodercidae)

Abstract Fourteen new species of the genus Thaiderces F.Y. Li & S.Q. Li, 2017 from Indonesia, Myanmar, and Thailand are described: T. shuzi Li & Chang, sp. nov. (♂♀), T. peterjaegeri Li & Chang, sp. nov. (♂), T. ganlan Li & Chang, sp. nov. (♂♀), T. ngalauindahensis Li & Chang, sp. nov. (♂), T. yangcong Li & Chang, sp. nov. (♂♀), T. zuichun Li & Chang, sp. nov. (♀), T. miantiao Li & Chang, sp. nov. (♀), T. jiazi Li & Chang, sp. nov. (♀), T. tuoyuan Li & Chang, sp. nov. (♂♀), T. fengniao Li & Chang, sp. nov. (♂♀), T. haima Li & Chang, sp. nov. (♂♀), T. chujiao Li & Chang, sp. nov. (♀), T. thamphadaengensis Li & Chang, sp. nov. (♂♀), and T. thamprikensis Li & Chang, sp. nov. (♂♀). In addition, two species of Psiloderces Simon, 1892 are transferred to Thaiderces: Thaiderces rimbu (Deeleman-Reinhold, 1995) comb. nov. (♂♀) and Thaiderces djojosudharmoi (Deeleman-Reinhold, 1995) comb. nov. (♂♀).

Composition. Thaiderces jian (♂♀) (the type species), T. vulgaris (Deeleman-Reinhold, 1995)  Embolic stubble aligned, almost as wide as bulb (Fig. 1K)  Lateral spermathecae similar to median spermathecae but embedded with ovoid duct structure (Fig. 2I)  Etymology. The species name is a noun in apposition derived from the Chinese pinyin shūzǐ (comb) and refers to the serrated stubble on the embolic stalk that resembles a comb.
Diagnosis. Males of T. shuzi sp. nov. can be distinguished from all other species of the genus by the unique structure of the male bulb with a long embolic stalk bearing serrated embolic stubble (Fig. 4A) that resembles a comb (vs. absence of serrated embolic stubble in congeners); females can be differentiated from congeners by two pairs of stalked spermathecae with globose distal parts ( Fig. 3A) (vs. one pair of spermathecae or spermathecae without stalk in congeners).
Distribution. Known only from the type locality (Fig. 29).     length of femur; cymbium dark with concentrated purplish spots, half the length of femur; bulb light yellow, narrow, and oblong, length/width ratio = 1.90; embolus thin and straight, arises distally, half the length of the entire bulb (Fig. 6).

Thaiderces peterjaegeri
Female. Unknown. Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin gănlăn (olive) and refers to the structure of the bulb that resembles an olive or a rugby ball (Fig. 8A).

Thaiderces ganlan
Diagnosis. Diagnostic features of males are discussed under T. peterjaegeri sp. nov. Females of T. ganlan sp. nov. can be distinguished by a pair of twisted ribbon-liked spermathecae, with globular distal ends two times wider than stalk (vs. spermathecae with globular heads three times wider than stalk in T. tuoyuan sp. nov., Fig. 6A).
Description. Male (holotype). Total length 1.63; carapace 0.63 long, 0.63 wide; abdomen 1.00 long, 0.75 wide. Carapace round and brown with 3 longitudinal brown bands, lateral bands three times wider than the median band ( Fig. 7C). Chelicerae brown (Fig. 28E). Clypeus dark brown medially and light brown laterally. Endites light brown. Labium dark brown. Sternum with dark brown pattern. Abdomen brown and elongated, dorsum with complex yellow dotted patterns, anteroventrally brown with pair of dark brown circular patches followed by a light brown elliptical patch, posterior part with a pair of yellow dotted lines laterally and a V-shaped mark medially. Legs uniformly brown; measurements: I 5.  (Fig. 8C, D): femur three times longer than patella; patella not swollen, tibia 2/3 the length of femur; cymbium dark with concentrated purplish spots, half the length of femur; bulb light yellow and elliptical, with a distinct protrusion arising distally, adjacent to embolus; embolus thick and branched, arising distally, almost equal in length to the entire bulb (Fig. 8A).
Female (Paratype). General features and coloration similar to that of male (Fig. 7D Endogyne with a pair of twisted ribbon-liked spermathecae with long stalks and globular heads, heads 2 times wider than stalks, stalks almost equal to the interdistance of stalk bases (Fig. 7A).
Distribution. Known only from the type locality (Fig. 29).   (Fig. 10D) (vs. the absence of lamina connected to the embolus in T. rimbu) and the embolic stalk is slanted at a 30° incline (Fig. 10D) (vs. embolic stalk rather round and curved in T. rimbu).
Female. Unknown. Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin yángcōng (onion) and refers to the entire structure of the bulb which resembles an onion bulb.
Diagnosis. Thaiderces yangcong sp. nov. is similar to T. djojosudharmoi, but males can be distinguished by the thin and long embolus (vs. a thick and short embolus in T. djojosudharmoi), a rather plump and rounded bulb (vs. a rather ovate bulb), and the presence of embolic stubble (vs. absence of embolic stubble); females can be distinguished by a pair of short, twisted, and rather distant wavy spermathecae (vs. two pairs of short petal-like spermathecae that are close together in T. djojosudharmoi).
Description. Male (holotype). Total length 1.95; carapace 0.70 long, 0.75 wide; abdomen 1.25 long, 0.90 wide. Carapace round and pale brown, with three longitudinal dark brown bands, median band only half the length of carapace, lateral bands three times wider than the middle band (Fig. 11C). Chelicerae brown (Fig. 27B). Clypeus dark brown medially and light brown laterally. Endites pale yellow. Labium light brown. Sternum with dark brown pattern. Abdomen elongated, dorsum with brown stripes medially (Fig. 11C), anteroventrally brown with pair of dark brown circular patches followed by a light brown elliptical patch, posterior part with a pair of yellow dotted lines laterally and a V-shaped mark medially.  (Fig. 12A-D): femur four times longer than patella; patella not swollen, tibia 2/3 the length of femur; cymbium darker anteriorly, half the length of femur; bulb light yellow, round with sparse embolic stubble; embolus thin and dark, arising distally, almost the same length as bulb (Fig. 12A).
Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin zuǐchún (lip) and refers to the overall structure of the spermathecae which is similar to a human lip.

Thaiderces zuichun
Diagnosis. Thaiderces zuichun sp. nov. is similar to T. miantiao sp. nov. but can be easily distinguished by a pair of stalked spermathecae with an oblong distal part connected to a wavy horizontal duct (vs. two pairs of strongly twisted spermathecae in T. miantiao sp. nov.).

Thaiderces miantiao
Male. Unknown. Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin jiázǐ (clamp) and refers to the spermathecae structure which resembles a face clamp (Fig. 15A).

Thaiderces jiazi
Diagnosis. Thaiderces jiazi sp. nov. can be distinguished from other species by the unique pattern on the carapace, with trident purplish stripes medially and purplish stripes laterally (Fig. 15C), a pair of spermathecae that resemble a face clamp (curved perpendicularly and oppositely directed), attached to a funnel-shaped structure posteriorly (Fig. 15A) (vs. stalked spermathecae with oblong heads connected by a horizontal arched duct in T. zuichun sp. nov.).
Male. Unknown. Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin tuŏyuán (oval) and refers to the ovoid shape of the bulb.

Thaiderces tuoyuan
Diagnosis. Thaiderces tuoyuan sp. nov. is similar to T. jian, but males can be distinguished by the obovate bulb (vs. oblong bulb in T. jian), the position of the entire bulb is a mirror image of that of T. jian but theembolus arises from the opposite position in the two species; females can be distinguished by having one pair of spermathecae (vs. two pairs in T. jian).
Distribution. Known only from the type locality (Fig. 29).  Etymology. The species name is a noun in apposition derived from the Chinese pinyin fēngniăo (hummingbird) and refers to the entire structure of the bulb, including the embolic stalk and laminar apophysis, resembling the head of a hummingbird.
Diagnosis. Thaiderces fengniao sp. nov. is similar to T. haima sp. nov. but can be distinguished by a lighter color of pale yellow and purplish pattern as a whole (vs. rather darker color of brown pattern as a whole in T. haima sp. nov.), the embolic stubble is divided into two rows (Fig. 19C) (vs. the embolic stubble is undivided in T. haima sp. nov.), presence of laminar apophysis adjacent to embolus (Fig. 19C) (vs. the absence of laminar apophysis in T. haima sp. nov.), and the tibia is 2/3 the length of femur (vs. tibia almost equal to the length of femur in T. haima sp. nov.); females can be distinguished by a pair of short tubular spermathecae (vs. a pair of circular doublet spermathecae in T. haima sp. nov.).
Distribution. Known only from the type locality (Fig. 29).    Etymology. The species name is a noun in apposition derived from the Chinese pinyin hăIimă (seahorse) and refers to the distal bending of bulb that resembles the head of a seahorse.
Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is a noun in apposition derived from the Chinese pinyin chùjiăo (antenna) and refers to the structure of the spermathecae that resembles two pairs of clavate antennae (Fig. 22A). Diagnosis. Thaiderces chujiao sp. nov. can be distinguished from other species by the two pairs of tubular spermathecae resembling two pairs of clavate antennae, lateral pair half the length of the median pair (Fig. 22A) (vs. circular spermathecae with with ovoid duct in T. haima sp. nov.).
Male. Unknown. Distribution. Known only from the type locality (Fig. 29). Etymology. The species name is an adjective referring to the type locality. Diagnosis. Thaiderces thamphadaengensis sp. nov. can be distinguished from other species of the genus by the distinct long, flat and tapered embolic stalk (vs. embolic stalk not flat and tapered in other congeners); females can be distinguished by two pairs of spermathecae, lateral pair with short stalks, median pair circular (vs. one pair of similar spermathecae, tubular or twisted spermathecae in other congeners).
Distribution. Known only from the type locality (Fig. 29).  26C) (vs. long embolus in T. vulgaris (embolus tip exceeds perimeter of bulb)), aligned arrangement of embolic stubble on embolic stalk (vs. embolic stubble divided into two rows in T. vulgaris), and palpal tibia is longer than the entire bulb (vs. palpal tibia is shorter than the entire bulb); females can be distinguished by a pair of tubular spermathecae laterally, connected with wavy horizontal ducts medially (vs. two pairs of spermathecae with lateral pair shorter than median pair).

Thaiderces thamphrikensis
Description. Male (holotype). Total length 1.62; carapace 0.62 long, 0.70 wide; abdomen 1.00 long, 0.55 wide. Carapace round and brown, with three longitudinal dark brown bands, lateral bands almost equally wide with the median band (Fig. 25C). Chelicerae brown (Fig. 27A). Clypeus dark brown medially and light brown laterally. Endites brown. Labium dark brown. Sternum with dark brown pattern, delimiting an inverted triangle medially. Abdomen elongated, dorsum with dark brown striped pattern, posterior with brown stripes, anteroventrally dark brown with pair of light brown kidney-shaped marks, followed by a horizontal, linear brown pattern medially, posterior part with pair of light brown vertical dotted lines laterally. Legs uniformly brown; measurements: I-II missing, III 3.50 (0.25, 0.25, 1.30, 1.10, 0.60), IV missing. Palp (Fig. 26A-D): femur 4 times longer than patella; patella not swollen, tibia almost equal   in length to femur, swollen; cymbium scattered with dark brown spots, 1/3 the length of femur; bulb pale yellow, pyriform, with a patch of aligned embolic stubble distally; embolus short and bent, arises distally.

Description. Described by
Distribution. Indonesia. Remarks. The somatic morphology and diagnostic features are similar to the type species of the genus; therefore, we transfer it to Thaiderces.