Stygophrynus orientalis, Seiter, Michael & Wolff, Jonas O., 2017

Seiter, Michael & Wolff, Jonas O., 2017, Stygophrynus orientalis sp. nov. (Amblypygi: Charontidae) from Indonesia with the description of a remarkable spermatophore, Zootaxa 4232 (3), pp. 397-408 : 399-406

Stygophrynus orientalis sp. nov.

( Fig. 1–5 )

Type material. Holotype: Adult female (NHMW 21944). Paratypes: Adult male (NHMW 21945); 5 Adult females, 5 adult males, 8 subadult specimens (NHMW 21946); 2 adult females, 1 adult male, 3 juveniles ( SMNS): Indonesia, Central Sulawesi province , Island Banggai (Pulau Banggai), all individuals were collected close to each other in October 2013, leg. P. Grabowitz.

Comparative diagnosis. Stygophrynus orientalis sp. nov. is easily distinguishable from S. moultoni by the presence of only one large spine with a smaller subsidiary basal spine on the antero-dorsal margin of the pedipalp basitarsus. Two big and well separated spines of equal size can be found antero-dorsal margin of the basitarsus in S. moultoni . Stygophrynus orientalis sp. nov. differs from Stygophrynus brevispina Weygoldt, 2002 and Stygophrynus cerberus Simon, 1901 in the count of dorsal and ventral spines of the pedipalp femur. Stygophrynus orientalis sp. nov. has four of these spines while females of S. brevispina have five dorsal and five ventral spines and S. cerberus harbors five dorsal spines. Furthermore, in adult males of S. brevispina not only T4 is strongly reduced in size but also T3. The cheliceral dentition allows distinguishing S. orientalis sp. nov. from S. sunda . In S. orientalis sp. nov. the uppermost tooth of the external row of teeth is bicuspid while it is not in S. sunda , furthermore the movable cheliceral finger harbors five teeth in S. orientalis sp. nov. and six in S. sunda . In S. dammermani the dorsal surface of the chelicera is smooth, and in Stygophrynus berkeleyi Gravely, 1915 it is roughened with small tubercles whereas, it is finely roughened with and harbors eight big tubercles in S. orientalis sp. nov. Stygophrynus cavernicola ( Thorell, 1889) and Stygophrynus longispina Gravely, 1915 exhibit five to six contiguous ventral spines distally of the large submedial ventral spine. Four contiguous spines can be found, respectively, on the dorso- and the ventrodistal margin of the pedipalp basitarsus of S. dammermani . In contrast none of the 26 examined specimens of S. orientalis sp. nov. harbored more than three contiguous spines on the dorso- or the ventrodistal margin. Stygophrynus dammermani and S. sunda can both be distinguished from S. orientalis sp. nov. by the count of trichobothria on the distitibia of leg IV, which is 21 in S. dammermani , 23 in S. sunda against 22 in S. orientalis sp. nov.

Description of female holotype. Color in life ( Fig. 4 ): Carapace, opisthosoma and pedipalps uniformly dark brown to blackish; walking leg segments distal to the patella are lighter colored.

Carapace ( Fig. 1 A, 4, 5D–F): 1.36 times wider than long, finely granular, with setiferous tubercles on the anterior margin. Cerotegument with regular, globular granules with a rough surface structure, based on crystal- and fiber-like particles. Short connecting fibers between granules and the underlying cuticle. Eyes well developed, elevated and large, more pronounced in median eyes; median eyes rounded with small triangular frontal process, visible from above.

Chelicera ( Fig. 1 B–D): Dorsal surface finely roughened with eight big tubercles, each with a setum, internal teeth row with four denticles, the lower tooth the biggest, the most dorsal tooth bicuspid of which the lower cusp is the larger one; external row with two teeth, the uppermost tooth bicuspid. Claw (movable finger) with five teeth, the proximal tooth the biggest, following teeth decreasing in size distally; teeth flattened and blunt. Cheliceral surface with many fine hairs.

Sternum ( Fig. 1 A): The first sternite (tritosternum) elongated with paired apical setae, stretching between pedipalp coxae and several other lateral setae facing distally; second and third sternites small and rounded with small setae; fourth sternite (metasternum) unpaired with six setae.

Pedipalps ( Fig. 1 A, E, 2A): Trochanter with twelve spines and several setiferous tubercles on antero-dorsal margin, one prominent large spine on the antero-ventral margin. Femur with four major spines and many small denticles on antero-dorsal margin, F2 largest one (F2> F3> F1> F4), one small spine between F2–F3 and F3–F4, two smaller spines internally close to the margin of trochanter, four major spines and four small spines on the anteroventral margin (FIII> FII> FIV> FI), between FII–FII and FIII–FIV one smaller spine more internally, the rest with several small spines in between, FIV closer to the ventral surface than the rest. Tibia with four major dorsal spines, T2 largest one (T2> T1> T3> T4), one small spine between T1–T2, two small spines between T3– T4, three small spines between T1 and the distal margin (some specimen only harbors two small spines between T1 and the distal margin on one pedipalp hand; compare Table 1 ), most distal one the smallest, four major spines on the antero-ventral margin, TII largest one (TII> TIII> TIV> TI), one small spine between TI–TII and TV– TIV, TI markedly curved. Basitarsus with one large submedial spine on antero-dorsal margin (lsmd-s), which has a subsidiary proximal basal spine (spb-s), one small setiferous tubercle (set) followed by three contiguous spines (cod-s) on the distal margin, these three spines decreasing in size proximally, the most distal the largest one, anteroventral margin with one large spine (lsmv-s) followed by three smaller spines (cov-s) on the distal margin, these three spines decreasing in size proximally, the most distal the largest one, a row of two to three long setae with thickened tips similar to those at proximal end of cleaning organ of the distitarsus at dorsal distal margin. Distitarsus spineless, with large well developed cleaning organ (co), with a row of short dorsal setae (co-ss) and 27 long setae (co-ls) ventrally, cleaning organ with five small cuspid tubercles (co-ct), a row of two to three long setae with thickened tips near proximal end of cleaning organ (rs). Pretarsus/ claw separated from distitarsus by an articulation.

Legs ( Fig. 1 A, F): Antenniform legs with 25 tibial and 46 tarsal articles; walking legs elongated, basitibia II and III with one segment, basitibia IV divided into four segments, fourth segment with single trichobothrium bt close to the distal margin, 22 trichobothria on distitibia, bc closer to sbf than bf (distance: 1.06 to 0.38 to 0.14 to 0.78, bt to bf to bc to sbf to stf1; mm), tarsi with well pronounced light transverse line, tarsal segment without oblique slit, arolium present.

Gonopods ( Fig. 3 C): Soft, cone-shaped with paired finger-like apically pointed projections. Ventrally covered by genital operculum harboring many setae on margin.

Description of male paratype. Male genitalia ( Fig. 3 A–B): Dark brown sclerotized regions on the distal end of the fistula. The LoL1 and the LoL2 blunt, the LoL1 being one third of the size of the LoL2, posterodorsal LoD smaller than LoL1 and blunt. Spermatophore organ covered ventrally by the genital operculum.

Spermatophore ( Fig. 3 D–G): The spermatophore consists of the stalk, the head and the sperm masses. The complete structure is about 2.68 mm in height. It bears two protruding sperm masses (sp) apically which are connected by a broad strip (bs). Two small upwardly directed processes emanate apically of the sperm masses (upper wings; uw). Lateral horns (lh) are well developed. Posterior extensions (pe) present but stout, connected with notched structures (ns), connected basally to the stalk. pe and ns linked like a hinge. The empty spermatophore consists of the same parts. One lateral wing is missing in the depictured emptied spermatophore.

The inner part is destroyed and the notched structures are dissolved. The region of the spermatophore head formerly bearing the sperm packages is lifted up nearly at an angle of 90 degree to the stalk.

Measurements (in mm). See Table 1 .

Etymology: The name refers to this species representing the easternmost record of the genus known to date.

Variability between analyzed specimens. The description above is based on the female holotype, but several important morphological variations within the 26 studied specimens were observed. In the female holotype the dorsal margin of the basitarsus harbors three contiguous spines (cod-s) distal of the large submedial spine (lsmd-s) which decreases in in size proximally. Differences in this pattern were found in several specimens. Sometimes the two distal spines are fused on their bases as it is the case in paratype male specimens ( Fig. 2 B, D). In one case the spination of the basitarsi differs from one another in the same specimen (compare Fig. 2 B and 2C). The spination of the disto-ventral margin of the basitarsus also exhibits variation. In the holotype female three contiguous spines proximally decreasing in size (cov-s) can be found distally of the large spine. In some specimens these can be reduced or only visible as setiferous tubercles ( Fig. 2 B), or enlarged and well pronounced ( Fig. 2 A, C–D). Furthermore, the form and shape of the subsidiary proximal basal spine on the pedipalp basitarsus can vary in size and the tip can be curved proximally or distally ( Fig. 2 B).

Variation was also observed in the region between spine T1 and the distal margin of the pedipalp tibia. In the holotype female three small spines are situated in this area ( Fig. 1 A, E). Out of 26 analyzed specimens eight showed an aberrant spination pattern (either on both sides or only on one side). These specimens harbor two or one spine with another “fused” second and third one in this region of the pedipalp tibia ( Fig. 2 D).

Comparative morphology of cerotegument structure. The cerotegument of S. orientalis sp. nov. exhibits regular, globular granules with a rough surface structure. There are short connecting fibers between granules and the underlying cuticle ( Fig. 5 D). The granule surface is built by both crystal- and fiber-like nano-particles ( Fig. 5 E, F). In Sarax curioi Giupponi & Miranda, 2012 (Charinidae) the globule surface is fine granular, which is comparable to the structure found in Charinus spp. ( Charinidae ) ( Wolff et al. 2017). Similar to S. orientalis sp. nov. there are connecting fibers between granules and the underlying cuticle ( Fig. 5 G, H), and the cerotegument surface is built by both crystal- and fiber-like nano-particles ( Fig. 5 I). In contrast, Charon cf. grayi (Gervais, 1842) (Charontidae) exhibits small globular crystals ( Fig. 5 C), forming the regular nubby granule surface ( Fig. 5 A, B), that has some similarity with that of S. orientalis sp. nov. However, fibers are lacking, and the overall structure is more regular.

Figures

FIGURE 1. Stygophrynus orientalis sp. nov. A Habitus of female holotype, dorsal and ventral view, respectively. B – D Female chelicera, denticles enhanced with white lines (B internal view; C external view; D external view, close-up on external teeth row). E Pedipalp (left ventral, right dorsal view), spines of femur and tibia numbered. F Distitibia and distal basitibia of walking leg IV, dorsal; trichobothria marked as follows: basitibia (bt = basitibial), distitibia (bf: basofrontal; bc: basocaudal; sbf: subbasofrontal; sbc-x: series caudal trichobothria; stf 1 x: series frontal trichobothria). Note: not all trichobothria are visible on this figure. Scale bars: A 20 mm, B – C 2 mm, D 0.25 mm E 2 mm, F 1 mm.

FIGURE 2. Stygophrynus orientalis sp. nov. Variability of pedipalpal spination. Distal part of pedipalp, pro-lateral view. A Holotype female (21944), tarsus of right pedipalp, left drawing, right original photograph. B Paratype male (# 2), tarsus of left pedipalp. C Paratype male (# 2), tarsus of right pedipalp. D Paratype male (# 3), tibia and tarsus of left pedipalp. Labels: see text. Scale bars: 1 mm.

FIGURE 3. Reproductive structures. A – B Detail of male gonopods, right gonopod enhanced by white lines (A ventral view, B dorsal view). C Female gonopods, dorsal view, gonopod enhanced by white lines. D Intact spermatophore, frontal view. E Intact spermatophore, lateral view. Arrow indicates the direction from which the female approaches the spermatophore. F Emptied spermatophore, frontal view. G Emptied spermatophore, lateral view. Arrowheads indicate former placement of the seminal packages. Scale bars: A – C 0.2 mm, D – G 0.5 mm.

FIGURE 4. Photographs of living adult Stygophrynus orientalis sp. nov. individuals in captivity. A female (above) and male (below). B Two adult males exhibiting agonistic behavior. C Adult female with protonymphs (shortly after moulting).

FIGURE 5. Cerotegument of Charinidae and Charontidae (after Wolff et al. 2017). A – C Charon cf. grayi (Negros Island, Philippines), D – F Stygophrynus orientalis sp. nov., G – I Sarax curioi (Pany Island, Philippines). SEM of air dried exuvia of carapace. A, B, D, E, G, H globular surface. C, F, I detail of colloidal particles. For interpretations see text. Scale bars: see figure.

Tables

TABLE 1. Measurements (mm) of female holotype anđ selecteđ paratype specimens. Abbreviations: Peđipalp tibia (T 1 T ³, T 1 the most đistal one); * Number of spines between anđ đistal margin of peđipalp tibia; ** Number of trichobothria on the basitibia anđ đistitibia of leg IV.

Carapace (length / width) Pedipalp Femur Tibia Tibia Spine T1 Tibia Spine Tƻ Tibia Spine T³	♀ holotype (21944) 6.84 / 9.³1 6.8ƻ 7.11 ƻ.1³ ƻ.³5 ƻ.04	♀ paratype (21946_7) 5.7ƻ / 7.76 4.87 5.74 ƻ.³ ƻ.54 ƻ.06	♀ paratype (21946_9) 6.1ƻ / 8.07 5.75 6.59 ƻ.17 ƻ.45 ƻ.11	Ƌ paratype (21945) 7.64 / 10.01 9.³5 10.³8 ƻ.71 ³.06 ƻ.9ƻ	Ƌ paratype (21946_³) 6.³1 / 8.98 7.³³ 8.98 ƻ.³7 ƻ.8³ ƻ.49	Ƌ paratype (21946_4) 6.4³ / 8.99 6.99 7.5 ƻ.41 ƻ.81 ƻ.49	Ƌ paratype (21946_5) 6.15 / 8.77 6.³6 8.ƻƻ ƻ.59 ³ ƻ.87	Ƌ paratype (21946_6) 5.86 / 8.ƻ³ 5.76 6.ƻƻ ƻ.45 ƻ.58 1.98	Ƌ paratype (21946_8) 6.44 / 8.ƻƻ 6.³ƻ 7.1³ ƻ.³6 ƻ.59 ƻ.18
Spines to margin* Basitarsus Distitarsus	³ ³.07 ƻ.49	³ ƻ.55 ƻ.³7	³ ƻ.69 ƻ.³8	ƻ ³.7 ³.48	ƻ‒³ ³.57 ³.³4	³ ƻ.99 ƻ.65	³ ³.16 ³.ƻ	ƻ-³ ƻ.³ ƻ.17	2 ³.ƻ4 ƻ.9ƻ
Walking leg II Femur Patella	9.95 1.58	8.7 1.5	10.8 1.7	1³.64 ƻ.16	11 1.9	10.5 1.4	11.ƻ 1.5	9.1 1.6	1³.5 ƻ
Walking leg III Femur Patella Basitibia Distitibia Basitarsus + claw Walking leg IV Femur	11.57 ƻ.³ƻ 11.77 4.68 4.16 11.ƻ³	9.7 1.6 9.5 4.ƻ ³.ƻ 9	11.6 ƻ.ƻ 11.7 4.8 4 10.6	14.9³ ƻ.³9 14.91 5.88 4.54 1³.³5	1ƻ.6 1.9 1ƻ.³ 5.ƻ 4 11.5	1ƻ.1 1.8 11.7 4.6 4 10.9	1ƻ.ƻ 1.7 1ƻ.ƻ 5.1 4 11.³	9.6 1.9 10.5 4.1 ³.5 9.7	14.³ ƻ.1 14.4 6.1 4.³ 1³.1
Patella	1.71	1.6	1.8	1.98	1.5	1.6	1.8	1.5	1.9
Basitibia Distitibia Basitarsus + claw Trichobothria**	1ƻ.³1 4.ƻ1 4.14 ƻ³	10.1 ³.6 ³.³ ƻ³	1ƻ.1 4.1 4.1 ƻ³	14.56 5.ƻ 4.41 ƻ³	1ƻ.9 4.4 ³.9 ƻ³	1ƻ.1 4.1 ³.9 ƻ³	1ƻ.9 4.ƻ ³.8 23	11 ³.6 ³.5 ƻ³	15.5 4.9 4.7 2³