Otostigmus (O.) multidens Haase 1887

4. Otostigmus (O.) multidens Haase, 1887

Figs 13 –17

Otostigmus (O.) loriae: Attems, 1930: 140;

Otostigmus (O.) multidens: Attems, 1930: 141; Otostigmus (O.) loriae: Schileyko, 1995: 81;

Otostigmus (O.) loriae loriae: Schileyko, 2007: 79; Otostigmus (O.) multidens: Lewis, 2014: 399.

Material. E Indonesia, West Papua Province, S Bird’s Neck, 05 – 09.09.2010: 1 ad [spm 1, largest, No. 7508], Kaimana 7–9 km NW, 3°35’02”S, 133°42’58”E, 25–200 m, primeval lowland rainforest on limestone, leg. DT; 1 ad [spm 2, No. 7509] + 2 ad [spm 3, СDT; spm 4 (larger one), No. 7510], Kaimana 47 km E, Triton bay, Kamaka (former Warika) village env., lake Kamakawalar and surroundings, 03°46’22”S, 134°12’02”E, 60–310 m, primeval lowland rainforest on limestone, leg. DT; 1 ad [spm 5, No. 7511], Kaimana 47 km E, Triton bay, Kamaka (former Warika) village env., lake Kamakawalar, 03°45’33”S, 134°12’05”E, 90 m, primeval lowland rainforest on limestone, leg. M. Kalninsh.

Range. Cambodia; Vietnam; The Philippines; West Malaysia (Pahang); Indonesia: Sumatra, Maluku Islands, West Papua; Papua New Guinea.

Remarks. Our specimens correspond well to the comprehensive description and drawings of Lewis (2014: 400) and can be readily recognized by the specific shape of the multi-dentated forcipular tooth-plates (Figs 13, 14). They differ insignificantly in having 22 (vs 21) antennomeres, of which 2.3– 2.7 (vs 2.3) basal ones with few long setae, complete paramedian sutures at tergites 4–20 (vs 6–20) and 1 additional dorsal (subapical) spine of coxopleural process (Fig. 15). The New Guinean specimens are also considerably larger reaching a length of 68–69 mm (spm 1).

It should also be noted that the studied specimens have tergites (11)13–20 with 9 well-recognizable keels (Fig. 16), latter being replaced in the Vietnamese and Malaysian exemplars by a single weakly developed medial keel. The degree of development of the tergal keels seems to vary quite widely in subgenus Parotostigmus (Schileyko, 2014: 177). As for Otostigmus s.str. Lewis (2007, 2010) regarded these structures as widely variable intraspecifically—from well-developed to nearly absent; for example Lewis (2007) noted that some exemplars of O. (O.) orientalis (which is type-species of the genus) have these keels but others lack them. Thus, the presence of tergal keels is a species-specific character for some species (eg, O. scaber Porat, 1876, O. amballae Chamberlin, 1913, O. orientalis), but varies significantly in others (eg, O. multidens). All studied specimens have spiracles with well-developed and deep atrium, spiracles of segment 3 are quite narrow (Fig. 17); similar conditions are found in the Vietnamese exemplars, too.

Otostigmus telus was described by Chamberlin (1939) from Pionierbivak at Mamberamo river (Indonesia, Papua Province) on the basis of a single adult(?) (48 mm long) specimen. Its short and meager description lacks drawings and important detail (eg, information about the structure of forcipular tooth-plates). However, Chamberlin stated that O. telus is “close to O. loriae [= O. multidens] Silvestri”. Lewis (2014: 408) considered this species as nomen dubium although in Bonato et al. (2016) it is listed among the valid species. Since we haven’t examined the type specimen and given its poor morphological diagnosis it is not included in our List of Papuan species.