Depreissia decipiens Deeleman-Reinhold & Floren, 2003

Deeleman-Reinhold, Christa L., Miller, Jeremy & Floren, Andreas, 2016, Depreissiadecipiens, an enigmatic canopy spider from Borneo revisited (Araneae, Salticidae), with remarks on the distribution and diversity of canopy spiders in Sabah, Borneo, ZooKeys 556, pp. 1-17 : 2-7

Taxon classification Animalia Araneae Salticidae

Depreissia decipiens Deeleman-Reinhold & Floren, 2003 Figs 1-4, 5-10, 11-13, 14

Depreissia decipiens Deeleman-Reinhold & Floren 2003: 336, figs 1-7 (description ♂ holotype)

Holotype.

MALAYSIA (BORNEO): Sabah, Kinabalu area, Sorinsim, ♂, 40 year old secondary forest adjacent to primary forest, 6°17'52"N, 116°42'3"E, 280 m.a.s.l., canopy fogging Vitex pinnata (L.), ( Verbenaceae ), tree 9 fog 1, 8.3.1997.

Additional material.

Sabah, 1 immature, same as holotype, canopy fogging Vitex pinnata (L.) tree 5, fog 1, 7.3.1997; Mt. Kinabalu National Park at Poring Hot Springs, primary forest, 6°2'37"N, 116°41'57"E, 500-700 m.a.s.l., 1♀, canopy fogging, Aporosa maingayi tree 6, fog 1, 28.3.1998; Mt. Kinabalu National Park at Poring Hot Springs, 6°2'42"N, 116°41'54"E, 1 immature, canopy fogging, Aporosa lagenocarpa , tree 8, fog 1, 29.3.1998; Mt. Kinabalu National Park at Poring Hot Springs, 6°2'58"N, 116°41'58"E 1 immature, Aporosa lagenocarpa tree, 19.2.1996; Kinabalu area, Monggis lowland primary forest, 6°13'17N, 116°44'14"E, 300 m.a.s.l., 2 immatures, canopy fogging Lithocarpus sp. ( Fagaceae ) tree 32, fog 1, 23.9.2006 (Fig. 14). All A. Floren, deposited in Naturalis Biodiversity Center, Leiden (RMNH).

Diagnosis.

The palpal structure is unlike that in any known salticid. Depreissia decipiens shares with the African species Depreissia myrmex the peculiar elongate, dorsally flat rhombus-shaped carapace, and the PLE widely separated and far removed from the anterior eyes. The rear part of the carapace is transformed. The palpal tegulum has a deep constriction, which divides it into an anterior and a posterior part, the latter bearing an elongate bifid tegular apophysis and a large chitinized grooved median apophysis directed downward along the longitudinal axis. The spermophore and filiform embolus are situated in the anterior part (Figs 12, 13).

Depreissia decipiens male is distinguished from the African species Depreissia myrmex by its larger size and accordingly longer legs, pale orange colour rather than dark as in Depreissia myrmex , and the ALE positioned posterolaterally instead of directly behind the AME. The posterior end of the carapace in Depreissia myrmex has an upturned posterior margin ( Wesołowska 1997: fig. 2); in Depreissia decipiens there is a central pustulous hump and a pair of large lateral pits (Figs 5, 8, 9; Deeleman-Reinhold and Floren 2003: fig. 6). Cheliceral promargin with 2 teeth (one in Depreissia myrmex ). Femora and some other segments of leg I with at least one spine (legs of Depreissia myrmex spineless). The pedicel is much longer and arched in Depreissia decipiens , shorter and straighter in Depreissia myrmex . Palp (Figs 11-13): the embolus runs transversely as half a coil along anterior half of the tegulum (Fig. 13), parallel to the spermophore, whereas there are two full coils in Depreissia myrmex . In decipiens the membranous tegulum is divided into an anterior and a posterior part, connected by a thin string of soft tissue, the posterior part bears at its base a bifid tegular apophysis (bta in Figs 11, 13) and a strong grooved dagger-like median apophysis which is directed basally (bta and ma, Fig. 13; Deeleman-Reinhold and Floren 2003: fig. 3); in Depreissia myrmex the apophysis is spout-like ( Wesołowska 1997: figs 3-5).

Redescription of the male.

Total length 4.10. Carapace length 1.55, width 1.00, height 0.80. clypeus height 0.10, maxillar height 0.35, width 0.15 at base, 0.25 in the middle, 0.20 distally, chelicerae length 0.50, width 0.25 in the middle, pedicel length 1.25, abdomen length 1.50, width 1.00. Eye sizes: AME 0.30, ALE 0.11, PME 0.03, PLE 0.18. Eye row widths: AME-AME 0.60, ALE-ALE 0.72, PME-PME 0.75, PLE-PLE 0.95.

Leg I (coxa-trochanter-femur-patella-tibia-metatarsus-tarsus = total) 0.25-0.15-0.60-0.30-0.50-0.40-0.20 = 2.40, leg II 0.30-0.10-0.60-0.30-0.50-0.40-0.30 = 2.50, leg III 0.30-0.10-0.70-0.30-0.50-0.50-0.25 = 2.65, leg IV 0.45-0.20-0.90-0.45-0.55-0.50-0.30 = 3.35. Total length of right and left legs differ by approximately 3-4%.

Spider orange, carapace as in diagnosis, maxillae hooked outward at right angle, chelicerae basal half deeply excavated mesally ( Deeleman-Reinhold and Floren 2003: fig. 5), promargin with 2 teeth, posterior margin with some granule-based setae. Intercoxal ventral triangles laterally between coxae II and III. Pedicel slightly shorter than abdomen, arched, with two prominent humps dorsally, surface dotted with seta-bearing granules. Legs vaguely banded orange/cream/black; all leg femora have one disto-dorsal spine; there are two lateral unpaired short thick spines proventrally on tibia I and one similar on metatarsus I; all other segments are spineless. Abdomen oblate with dorsal scutum over 5/6 of the dorsal surface, showing a vague broad dark band anteriorly, continued on the flank and one near the rear and with several chevrons in between. Pulmonary plates large, triangular.

Palp: see diagnosis. Tibial apophysis short and straight (Fig. 11). Cymbium tip lacking central groove, there is a clear rim bordering anteriorly the cavity which hosts the bulb. The embolus is directed retrolaterally, it is not cradled.

Description of the female

(Figs 2-7). Total length 4.40, carapace length 1.60, width 1.00, height 0.80, clypeus height 0.10, maxillar height 0.30, width 0.15 at base, 0.25 in the middle; chelicerae slightly excavated, 0.40 long, 0.20 in the middle, pedicel length 1.25, abdomen length 1.70, width 1.00. Legs I and II lost, leg III 0.40-0.20-0.70-0.30-0.60-0.50-0.30 = 3.00, leg IV: 0.50-0.25-0.90-0.40-0.55-0.50-0.30 = 3.40; palp femur length 0.40, width 0.10, tibia length 0.15, patella length 0.15, tarsus length 0.30, width 0.20.

Somatic characters in female similar to male, slightly larger with slightly longer legs. Eyes, sculpture of carapace, colour and integument ornamentation as in male; maxillae as in male, chelicerae simple, mesal excavation only slight, with two small teeth. Palpal tarsus white, slightly flattened, no claw visible with microscope objective lens 6.6 x enlargement. Intercoxal ventral triangles and pedicel as in male. Femoral spines weak or absent. Abdomen lacking dorsal scutum.

Epigyne: spermathecae relatively large, adjacent to one another in the vertical midline. Copulatory openings posterior, funnel-shaped, with a small atrium and continued in a narrow tubiform duct (insemination duct), almost straight, bordering the spermathecae along lateral-ventral sides. The duct tightly loops mesally (see arrow in Fig. 3), to continue along the dorsal surface of the spermathecae, then returns back lateral-wards in a series of vertical coils; at the lateral end it returns back straight on the ventral side again to dive down at mesal end to merge into the spermathecae.

Note.

In many non-salticid spider species with a filiform embolus have it supported during copulation by a sclerite. We suppose that in this salticid the conspicuous s-shaped dagger-like median apophysis ventrally on the tegulum of the male palp serves that purpose. It penetrates the opening of the insemination duct supporting the embolus, the free part of which it matches in length (Fig. 13); this length approximates also the length of the spermathecae, so that the tip of the embolus and median apophysis reach approximately the point of the first tight loop (arrow, Fig. 3). The sperm consequently has to travel on towards the spermathecae through the long trajectory of twists and curls of the insemination duct. It can be expected that the inner wall of the distalmost section is clothed with specialized cells or glands.

Relationships.

It is difficult to assess the taxonomic position of Depreissia within the Salticidae . There is complete lack of conformity in body shape and structure of genital organs with the ant-mimicking Myrmarachninae. Neither do they fit in Lyssomaninae: eyes in 4 rows instead of 3 characterizes Depreissia myrmex but not Depreissia decipiens and the genital organs are of a clearly different type. The structure of both palp and epigyne in Onomastus Simon has a certain superficial resemblance ( Benjamin 2010, Prószyński and Deeleman-Reinhold 2013), but the conformation of genital organs is incompatible with that in Depreissia . The bipartite tegulum, the embolus tip not resting on cymbium tip, the presence of a sophisticated median apophysis and the unusual structure of the epigyne are key factors. A median apophysis is found mostly in primitive salticid clades, such as Cocalodinae ( Maddison 2009). In Depreissia , the median apophysis is positioned on the tegulum clockwise and at some distance from the embolus. The nearest genera with a comparably structured palp with similarly positioned median apophysis can be found in a recently described series of genera from New Guinea ( Maddison 2009). We suggest the species of the genus Cucudeta Maddison to be at present the nearest known relative of Depreissia . This is also supported by the similar structure of the epigyne, with openings in posterior pockets, long ducts rising forwards in lateral arch, looping, and entering the anterior end of the spermathecae (see also Maddison et al. 2016). Although morphology in Cucudeta is not particularly ant like, this spider has been observed walking with a specific fluid gait while keeping the second pair of legs in the air ( Maddison 2009), suggesting a tendency toward ant mimicry.