Mangatangi parvum, Taylor, Christopher K., 2013

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 : 61-62

Mangatangi parvum sp. n. Figure 1

Holotype.

♂. New Zealand, AK. Mangatangi, Hunua Ra., 8 Feb– 8 Mar 1977, I. Barton, ARA Kauri Seed Project, pit trap.

Paratypes.

1 ♀, as for holotype; 1 ♂, Cuvier Is, July, R. Forster.

Etymology.

From the Latin parvus, small, in reference to its small size compared to other New Zealand Enantiobuninae .

Diagnosis.

Mangatangi parvum can be distinguished from all other New Zealand Enantiobuninae by the presence of a well developed tooth comb on the pedipalpal tarsal claw. It can be distinguished from Monoscutum titirangiense , Acihasta salebrosa and Templar incongruens by its relatively long legs and unsclerotised dorsum. It differs from ‘Megalopsalis’ triascuta, all Pantopsalis and most Forsteropsalis species in the absence of either a mediodistal apophysis or hypersetose region on the pedipalpal patella, from Pantopsalis species by its relatively bowed cheliceral fingers, and from Forsteropsalis species by the absence of denticles on the medial side of the pedipalp coxa. Mangatangi parvum can also be distinguished from all other New Zealand species, so far as is known, by its genital morphology: all other New Zealand species investigated to date have a relatively long glans that is either narrow in lateral view (most species) or possesses a distinct dorsal keel ( Pantopsalis ). The deep and short glans of Mangatangi parvum is also distinct from that of Enantiobuninae elsewhere: Neopantopsalis species have a very elongate and relatively flat glans, and Megalopsalis and Spinicrus species have a short but also distally flattened glans. The only other Enantiobuninae in Australasia to possess comparatively deep glans are Australiscutum and Tercentenarium linnaei ; Mangatangi parvum differs from Australiscutum in possessing relatively long legs and retaining an anterior grill of spines over the spiracle, and from Tercentenarium linnaei in lacking a large dorsolateral flange at the junction between shaft and glans. The glans of Thrasychirus has never been illustrated in lateral view, but Mangatangi parvum is clearly distinguished from that genus by possessing paired bristle groups at the junction between shaft and glans rather than single bristles.

Description.

Male (Figs 1 a–b, d–e, g–i, l): Total body length 2.06-2.74 (larger value in all measurements represents holotype), prosoma length 0.97-1.19, prosoma width 1.76-2.01. Dorsal prosomal plate mostly light orange-yellow, unarmed except short, spinose black setae scattered over entire body; anterior propeltidium lighter yellow-cream, supracheliceral groove extending roughly halfway between anterior margin of carapace and ocularium; median propeltidium with diffuse purple stripes along border with anterior propeltidium with diffuse silver-white markings behind purple stripes, dark brown markings on lateral edge of dorsal prosomal plate; ocularium silver with black stripes margining eyes, unarmed; postocularium not distinguished from remainder of posterior propeltidium. Mesopeltidium forming raised ridge, medially pale yellow, laterally dark brown. Ozopores on raised lateral lobes, anterior lobes of prosoma and ozopore lobes dark brown, posterior of ozopore lobes silver-white, remainder of lateral shelves mostly yellow with dark brown lateral margins broadening to diffuse dark brown patch at about three-quarters of distance from front of prosoma. Metapeltidium and dorsum of opisthosoma with background colour of purple broken by pale yellow mottling, particularly along segment boundaries, longitudinal mediolateral broken stripes of silver-white present as well as longitudinal medial rows of silver-white spots, sides of opisthosoma with purple background heavily broken by pale yellow punctations. Mouthparts white; coxae proximally pale yellow; coxae I and II distally with purple mottling, coxae III and IV with dark yellow-brown mottling laterally; genital operculum pale yellow; venter of opisthosoma mottled light purple with pale yellow stripes along segment boundaries.

Chelicerae: Segment I 2.85-3.51, segment II 3.82-4.62. Segment I ventrally cream, dorsally orange-yellow, sparsely denticulate dorsally; segment II inflated, orange-yellow, densely dorsally and sparsely ventrally denticulate. Cheliceral fingers (Fig. 1d) long, bowed, movable finger with setae close to median tooth.

Pedipalps: Femur 1.53-2.13, patella 0.65-0.77, tibia 0.71-1.03, tarsus 1.80-2.47. Coxae unarmed. Femur to tarsus long, slender, unarmed, femur to tibia cream with paler distal ends to each segment, tarsus off-white with yellow-brown shading at distal end. Patella and tibia (Fig. 1e) straight, patella without distal prolateral apophysis or hypersetose region. Plumose setae absent. Microtrichia on distal half of tarsus only. Claw with ventral tooth-comb.

Legs: Leg I femur 2.99-3.80, patella 0.71-0.91, tibia 2.93-3.87; leg II not preserved; leg III 2.56-3.38, patella 0.77-0.93, tibia 2.70-3.45; leg IV femur 4.05-5.01, patella and tibia not preserved. All segments unarmed. Trochanters pale yellow, trochanters III and IV with dark yellow-brown mottling laterally. Femora to tarsi pale yellow, patellae and distal ends of femora and tibiae darkening to orange-yellow. Leg II not preserved; tibia IV with three pseudosegments.

Penis (Figs 1 g–i): Glans noticeably short and deep, sides parabolic in ventral view. Bristle groups of medium length. Tendon short, not extending far behind bristle groups.

Spiracle (Fig. 1l): Curtain of distally anastomosing spines extending over entire spiracle; shortening to cluster of tubercles (possibly lace tubercles) at medial corner.

Female (Figs 1c, f, j–k): Coloration similar to that of male. Other features as for male except for following: Chelicerae not enlarged, unarmed, segment I without ventral spine. Pedipalp (Fig. 1f) with microtrichia over entire patella, tibia and tarsus except glabrous dorsal line on patella and tibia. Ovipositor (Figs 1 j–k) with single pair of seminal receptacles.

Phylogeny.

Mangatangi parvum is probably related to the clade formed by Forsteropsalis and Pantopsalis , with which it shares the presence of sharp papillae on the glans, and of setae close to the major tooth of the mobile finger of the chelicera (this last feature is also present in Neopantopsalis ). The retention in Mangatangi parvum of a plesiomorphic tooth-comb on the pedipalpal tarsal claw, together with Mangatangi parvum 's distinctly short glans, could suggest a sister relationship between Mangatangi parvum and the Pantopsalis + Forsteropsalis clade, but this should perhaps be treated with caution. Pantopsalis rennelli and Pantopsalis cheliferoides each retain reduced teeth arrays (a single tooth in the latter species) on the tarsal claw, and that of Pantopsalis albipalpis has a ventral rugose area that may correspond to the remains of the tooth-row. The loss of the tooth-row in Pantopsalis and Forsteropsalis has therefore happened at least partially in parallel. As regards the short glans of Mangatangi parvum compared to the long glans of Pantopsalis and Forsteropsalis , our understanding of enantiobunine phylogeny is not yet robustly resolved ( Taylor 2011) and it is questionable which state is plesiomorphic for the clade.