Pantopsalis cheliferoides (Colenso, 1882)

Taylor, Christopher K., 2013, Further notes on New Zealand Enantiobuninae (Opiliones, Neopilionidae), with the description of a new genus and two new species, ZooKeys 263, pp. 59-73 : 67-70

Pantopsalis cheliferoides (Colenso, 1882) Figure 4

Phalangium (Phrynus) cheliferoides Colenso 1882: 166.

Pantopsalis cheliferoides ( Colenso 1882): Vink in Nicholls et al. 2000: 46, Taylor 2004: 65 (as nomen dubium).

Specimens examined.

1 ♂, New Zealand, GB. Lake Waikaremoana, 19 November 1975, G. W. Ransay, beating; 1 ♂, New Zealand, GB. Te Urewera National Park, Lake Waikaremoana, Kaitawa, 38°46'S, 177°83'E, 18 November 2004, D. King, on outside of house.

Description:

Male: Total body length 3.55-4.03 (former measurement refers to 2004 specimen), prosoma length 1.62-2.06, prosoma width 2.55-3.70. Dorsal prosomal plate medium brown, with some yellowish patches laterally; anterior propeltidium and ocularium heavily denticulate, remainder of prosoma unarmed. Dorsum of opisthosoma dark purplish brown with few white spots medially in one specimen, longitudinal purple medial stripe in other; larger white spots in present in central part of opisthosomal dorsum, comparable to lateral ‘arms’ of median stripe in females of other Pantopsalis species. Coxae medium brown mottled with honey brown; venter of opisthosoma medium purplish brown mottled with lighter purple.

Chelicerae: Segment I 4.73-6.23, segment II 6.36-8.47. Segment I medium brown with cream patches at distal end; segment II orange-brown; both segments heavily denticulate. Segment II inflated in larger specimen, slender in smaller. Cheliceral fingers (Fig. 4c) short, mobile finger crescent-shaped.

Pedipalps: Femur 1.81-2.32, patella 0.97-1.15, tibia 1.01-1.18, tarsus 2.10-3.02. Femur light purple at base, remainder of pedipalp shining white. Patella and tibia (Fig. 4d) prolaterally hypersetose, patella bulging prodistally but without distinct apophysis. Microtrichia on distalmost end of tarsus only. Tarsal claw with single ventral tooth.

Legs: Leg I femur 7.91-8.56, patella 1.36-1.58, tibia 6.03-6.14; leg II femur 13.25-13.69, patella 1.82-1.80, tibia 11.18-11.47; leg III femur 6.91-7.38, patella 1.32-1.45, tibia 5.22-5.48; leg IV femur 9.88-10.81, patella 1.57-1.59, tibia7.53-7.38. Femora evenly but irregularly denticulate, except distal third of femur II unarmed; remaining segments unarmed. Legs medium brown mottled with yellowish, tibiae and tarsi tinged with purple, tibiae spotted with white; tarsi with white band at base of telotarsi. Tibia II with five pseudosegments; tibia IV undivided in larger specimen, with two pseudosegments in smaller.

Penis (Fig. 4 e–f): Glans medium length, sides parabolic in ventral view; subtriangular in lateral view but not markedly flattened, slight dorsomedial bulge but keel essentially absent. Bristle groups short. Tendon long.

Comments.

There is some variation in coloration between the two specimens available, most notably the presence of a medial stripe on the opisthosoma of one but not the other, with the former specimen also being overall lighter in coloration than the latter. It is possible that this difference may reflect differences in maturity between the two specimens, similar to what has been recorded for other Opiliones species ( Shultz 2008). Such long-term darkening after moulting may also explain the anomalously pale specimens of Pantopsalis albipalpis recorded by Taylor (2004).

Long regarded as something of a mystery after its initial description by Colenso (1882), Pantopsalis cheliferoides was referred to only in footnotes by Forster (1944) and Marples (1944), and treated as a nomen dubium by Taylor (2004) due to the poor condition of the type specimen. This was unfortunate as, with the recognition of ‘Pantopsalis’ wattsi Hogg 1920 as a species of Forsteropsalis ( Taylor 2011), Pantopsalis cheliferoides was the only species of Pantopsalis described from the North Island. The two specimens examined here, though collected some distance from the type locality, are consistent with Colenso’s (1882) original description and discernable features of the type specimen ( Taylor 2004) and, in the absence of evidence to the contrary, can be identified as Pantopsalis cheliferoides . This species can, therefore, be confirmed as distinct from other identifiable species of Pantopsalis .

The absence of a distinct dorsal keel on the glans of the penis clearly distinguishes Pantopsalis cheliferoides from all other Pantopsalis species except Pantopsalis luna and possibly Pantopsalis pococki (for which the genital morphology remains unknown). Pantopsalis pococki has a very distinct colour pattern, with transverse light coloured stripes on the dorsum of the opisthosoma ( Taylor 2004). Pantopsalis luna lacks a ventral tooth on the pedipalpal tarsal claw, has the ocularium unarmed with denticulation on the prosoma restricted to the anterior propeltidial region, and has narrow transverse stripes on the dorsum of the opisthosoma (personal observations, male specimens from Waiho Gorge, South Island, cited by Taylor 2004).

The presence of dimorphic males as described for other Pantopsalis species by Taylor (2004) in both Pantopsalis listeri and Pantopsalis cheliferoides is of note. Previous species in which this phenomenon has been observed ( Pantopsalis albipalpis , Pantopsalis coronata , Pantopsalis johnsi and Pantopsalis phocator ) all belong to the well-marked species group whose members possess a strong dorsal keel on the glans ( Taylor 2004) and it was previously unknown whether such male dimorphism occurred outside this species group. Its presence in the two species treated herein indicates that it does, and it may indeed be a synapomorphy for Pantopsalis as a whole.

Key to males of Pantopsalis

The last author to provide a key to species of Pantopsalis was Roewer (1923). Since then, a number of species have been described, several of the species referred to by Roewer have been synonymised, and characters of the chelicerae referred to by Roewer have been shown to vary within species ( Taylor 2004). Therefore, the opportunity is taken to provide an updated key to Pantopsalis males. Pantopsalis halli Hogg 1920 is omitted from the following key, as it is currently based only on a female specimen and not identifiable ( Taylor 2004). Pantopsalis albipalpis and Pantopsalis johnsi are not currently distinguishable, but Taylor (2004) refrained from synonymising them on the basis of their widely disjunct distributions. Their relationship requires further investigation.