Martensiellus tenuipalpus Schwendinger, 2006 (from original description)
- M.t. (male) (holotype) American Museum of Natural History; #
- M.t. (male) (paratype) Museo Civico di Storia Naturale "Giacomo Doria"; #
- Colouration (in alcohol) and surface texture: Ground colour light orange, with indistinct darker pattern on dorsal scutal elevations (probably lightened by long-time preservation in alcohol; Fig. 1). A finely granular surface on prosoma, genital operculum, chelicera (except for fingers), legs and palpus (except for tarsi).
- Carapace region with rounded, slightly anteriad-inclined eye tubercle carrying a small pointed tip; carapace-opisthosoma bridge absent; no lateral tubercles in posterior part of carapace region. Dorsal scutal areas of opisthosoma region only indistinctly elevated; ventral scutal areas moderately swollen and pallid (Fig. 3). Ventral scutum and opisthosoma region of dorsal scutum densely covered by short hairs (Figs 1–3). Palpal coxa with small ventral process; leg coxa I with indistinct anterolateral process; leg coxae II and III with distinct anteroproximal processes, no posteroproximal process on coxa II (Fig. 2); dorsal side of leg coxa IV without tubercles. Genital operculum somewhat triangular, wider than long; posterior margin of stigmatic pit without tubercle (Fig. 2).
- Chelicera (Fig. 4): Hand weak, with a few small hairs dorsally; proximal article with a higher dorsodistal and a lower dorsomedian boss, no ventral process.
- Palpus (Fig. 5): Trochanter with slightly distad-inclined ventral process; femur short, with indistinct, broadly rounded ventroproximal boss, no process; tarsus cylindrical, exceptionally thin in distal half, there about as deep and wide as claw (possibly a sexual dimorphism).
- Legs (Figs 6–9) 1342 (from shortest to longest), tarsal formula 1-1-2-2; tarsi I and II somewhat ovoid (Figs 6–7), with a deep pore dorsally; tarsus of leg II about 1.6 times longer than deep (Fig. 7).
- Penis (Figs 11–14): Truncus fairly robust, slightly constricted midway, from there widening to a second moderate constriction below glans; distal margin of truncus widely rounded; several subapical setae laterally, two on each side separated from other setae and flanking proximal part of glans. Glans distad-directed, wider than truncus at that point, slightly projecting beyond distal margin of truncus; lateral sclerites wide, somewhat scoop-shaped, their outer part flat and their inner part projecting dorsad; median plate rectangular, longer than wide (visible only in expanded state; see Fig. 16 for paratype), lying dorsally of lateral sclerites (as in Biantoncopus, but not in Palaeoncopus); stylus slender, with bifid tip but without pair of subapical teeth; membranous tubes wide, distally truncate and bent dorsad, lying between stylus and a somewhat pentagonal median knob. In expanded state (see Fig. 16 for paratype) median plate and stylus of glans protruding distad, and membranous tubes folded posteriad, as in the penis of Biantoncopus fuscus Martens & Schwendinger (see Martens & Schwendinger 1998: figs 64– 65).
- Measurements of male holotype (male paratype in parentheses): Body 3.51 (3.47) long, 2.18 (2.18) wide; carapace region 1.04 (1.02) long, 1.30 (1.30) wide; palpus 3.22; legs: I 3.37, II 4.81, III 3.56, IV 4.58.
- Variation. The male paratype is more strongly pigmented than the holotype. Its ground colour is amber, with dark brown horizontal bands on dorsal scutum and with a dark reticulation in the carapace region; leg femora to metatarsi are darkened, leg tarsi and palpal tarsus light brown; its ventral body side is mostly amber, only the lateral margin of the ventral scutum and patches behind coxa IV and genital operculum are darkened. The ventral process on the palpal trochanter of the paratype is ventrad-directed (Fig. 10) rather than slightly distad-directed as in the holotype (Fig. 5). The penis of the paratype has a slightly more rounded distal margin (Figs 15–16), but otherwise it is very similar to that of the holotype (Fig. 13).
- female unknown
- Location: Borneo (Baleh River (Kapit), Sarawak; 2°01'N 112°56'E)
- Two females from other parts of Borneo possess the same characteristics in somatic morphology (tarsal formula 1-1-2-2, leg tarsi/tarsomeres fairly large, a tarsal pore present on legs I and II) that place M. tenuipalpus apart from all other described sandokanid species and presumably belong to this genus, but generic placement without conspecific males is uncertain.