Pandirodesmus jaggernauthi, Vandenspiegel & Golovatch & Rutherford, 2022

Vandenspiegel, Didier, Golovatch, Sergei I. & Rutherford, Mike G., 2022, The millipede genus Pandirodesmus Silvestri, 1932 in Trinidad and Tobago, Caribbean, with the description of P. jaggernauthi sp. nov. from Trinidad (Diplopoda, Polydesmida, Chelodesmidae, Pandirodesmini), Zootaxa 5104 (4), pp. 567-576 : 569-575

publication ID	https://doi.org/ 10.11646/zootaxa.5104.4.6
publication LSID	lsid:zoobank.org:pub:549D3E97-8172-4040-9E9A-7B19D2EC49CF
DOI	https://doi.org/10.5281/zenodo.6333342
persistent identifier	https://treatment.plazi.org/id/03903824-FFE9-5C38-FF59-F922FB6EBAEE
treatment provided by	Plazi
scientific name	Pandirodesmus jaggernauthi
status	sp. nov.

Treatment

Pandirodesmus jaggernauthi View in CoL sp. nov.

Figs 1 C, D View FIGURE 1 , 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5

Type material

Holotype male ( FSCA), TRINIDAD, W of Cerro del Aripo, 11.XII.2015, 10.7331°, -61.2705°, M.G. Rutherford leg. Paratypes: 1 male (SEM), 2 females ( FSCA), same data as for holotype.

Diagnosis

A small-sized (ca 10 mm) millipede with unequal, alternating much longer anterior and much shorter posterior legs per body ring, particularly similar to P. rutherfordi by sharing all somatic characters and rather simple gonopods. The two species differ in the shape of the gonopodal telopodite which shows in the new species a longer and more strongly curved primary branch, a smaller prefemoral process with fewer “folds”, and a longer and slimmer secondary branch ( Figs 4 B,C,F View FIGURE 4 ). See also Key below.

Etymology

The new species is named in honour of Dan Jaggernauth, a Trinidadian naturalist who was guiding the hike on Cerro del Aripo when the first evidence of P. jaggernauthi was discovered. He is a dedicated and active member of the Trinidad & Tobago Field Naturalists’ Club and has spent his life sharing his love and extensive knowledge of the wildlife of Trinidad & Tobago with residents and visitors to the islands.

Description

Length ca 10 mm, width of midbody rings 1.2 mm, W/L ratio 12%. Body with 20 rings, including penultimate apodous segment and telson (formula 19p+1a+T, according to Enghoff et al. 1993). All of body surface heavily encrusted with dark grains of sand except prozonae, clypeus/labrum, paraprocts, and gonopods ( Figs 1B View FIGURE 1 , 3A View FIGURE 3 ).

Head smooth, facial setae short, translucent, slightly emerging from the coating, number difficult to assess ( Fig. 3A View FIGURE 3 ). Epicranium with two dorsal knob-like structures ( Fig. 3D View FIGURE 3 ). Labrum with three smoothly rounded teeth and a single row of 14 short labral setae ( Fig. 3A View FIGURE 3 ). Clypeus with two rows of setae, one supra labral with 6 setae, 3 on each side, and above of this a row of long setae, four on each side ( Fig. 3A View FIGURE 3 ). Antennae short, slightly clavate, densely setose ( Fig. 3C View FIGURE 3 ), reaching past midlength of collum; in length, antennomere 2>5>3>4>1>6>7, antennomere 3 with three long setae on knobs, 4 with one similar seta and knob as well. Terminal antennomere (disc) with four long sensory cones located together inside a membranous area.

Gnathochilarium as usual for a polydesmidean ( Fig. 3B View FIGURE 3 ). Prementum smooth and depressed; mentum (me) smooth. Lamellae linguales each with three strong setae, stipites with a mediobasal field of setae, lateral margin in distal half with a row of strong setae; cardo small, kidney-shaped.

Surface of pro- and metazonae smooth, glabrous ( Figs 3 View FIGURE 3 D-G). Collum short, narrow, inconspicuous, with four narrow, tubular projections arising from anterior margin on either side of midline. Body rings 2 to 6 narrower than following ones until 15th, thereafter gradually tapering towards telson. Metazonae smooth with neither striae nor grooves; strictures distinct; surface of prozonae alveolate, covered with very small rounded depressions, limbus shortly before margin with an irregular row of short setiform filaments ( Fig. 3H View FIGURE 3 ); margin finely denticulate/spiculate ( Fig. 3H View FIGURE 3 ). Metaterga 2–19 each with 1+1 similarly coniform, tubular, asetose, large projections directed anterolaterad ( Fig. 3D View FIGURE 3 , tp), one per side; projections on 4 and 5 substantially longer and subdigitiform; projections becoming smaller towards body ring 19 and progressively more so caudad, reduced to short stubs on 18 and 19; pore formula: 5, 7, 9, 10, 12, 13, 15–18, ozopores opening subapically on projections ( Fig. 3L View FIGURE 3 , oz). Posterior to the two large projections occur two small tubular projections overtopped by a small seta only visible on crassate specimens ( Fig. 3K View FIGURE 3 ). Sterna smooth, glossy, without noticeable modifications ( Fig. 3I View FIGURE 3 ).

Preanal ring with 2 lateral and 6 marginal subapical knobs each surmounted by a long seta. Epiproct short, subtriangular, extending slightly beyond distal paraproctal margins ( Fig. 3F View FIGURE 3 ), with four small, subapical spinnerets giving rise to one long seta each. Anal valves smooth, with two strong setae on each valve. Hypoproct small, semilunar with two prominent knobs supporting one long seta each ( Fig. 3J View FIGURE 3 ).

Legs very long and slender, alternating longer (anterior pair) and short (posterior pair) per ring ( Fig. 3O View FIGURE 3 ). Legs th

1 short; legs 2 and 3 longer. From body ring 3 through the last podous ring (18); posterior legs about 2/3 as long as anterior legs, but arising more ventrally. Starting with legs 3, each leg with tubular spiracles arising dorsally above coxae ( Figs 3M, N View FIGURE 3 , tg). Podomeres of midbody legs as follows: coxae short, normal in appearance; prefemora and femora moderately long and slender; postfemora nodular; tibiae short, but broad, tarsi generally long and slender, with slight to moderate nodular swellings at ¼ lengths, tapering distad; in length, tarsus> femur> prefemur> postfemur> coxa> tibia ( Fig. 3P View FIGURE 3 ). Claws absent from legs 1-3, following ones narrow, fine, difficult to distinguish between the surrounding long filiform setae, only slightly larger and wider than claws ( Fig. 3Q View FIGURE 3 ). Coxa, prefemur, femur and postfemur clothed with numerous long and apically plumose/dendroid setae ( Fig. 3R View FIGURE 3 ).

Gonopodal aperture ovoid and minute, located entirely within metazonum 7; rims smooth. Gonopods in situ ( Fig. 4A View FIGURE 4 ) held parallel to each other, telopodites fully exposed. Coxae small, closely appressed together, each coxa with two distocaudal macrosetae. Acropodite comprising three large branches: a prefemoral process (pfp), a secondary branch (sb), and a primary branch (pb). Primary branch forming a hook-like structure, being the longest, supporting a prostatic groove and divided distad into a solenomere and a “tibiotarsus” ( Figs 4A View FIGURE 4 , C-F). The secondary branch slightly shorter than the primary branch, wide basally, curved and progressively tapering apically ( Figs 4C, F View FIGURE 4 ). Prefemoral process largest, extending distad for ~2/3 length of primary branch, expanding anteriad into an irregularly folded lamina ( Figs 4A, C View FIGURE 4 ).

Paratypes: males same as holotype, females generally slightly larger in size than males (maximal length 12 mm, maximal width 1.4 mm).

Distribution and habitat

All collection sites of P. jaggernauthi were in higher elevations of the Northern Range of Trinidad. The type locality ( Fig. 1A View FIGURE 1 ) was alongside a bench trail (10.7331°, -61.2705°, 658 meters elevation) in lower montane forest, the microhabitat was the soil layer just below the leaf litter in amongst some low-lying vegetation, there was some degree of disturbance to the habitat indicated by the presence of introduced plant species such as common bamboo ( Bambusa vulgaris ). The two other sites where specimens were found (UWIZM.2017.29.1 the partial remains of an adult on El Cerro del Aripo at 10.7306°, -61.2549°, 816 meters elevation on 20 May 2014; UWIZM.2016.37.3 one adult female on Naranja at 10.7365°, -61.3970°, 808 meters elevation on 18 September 2016) were in primary montane cloud forest ( Helmer et al. 2012).

Although extensive surveying for other organisms living in leaf litter has been undertaken by MR at many sites throughout Trinidad, no other Pandirodesmus have been found at lower elevation. This contrasts with the location of collection sites for P. rutherfordi in Tobago which occurred at much lower elevations and in more heavily disturbed places, at one site several individuals were found in the concrete and stones from a ruined house within a few meters of the sea. This shows that different species of Pandirodesmus seem to be adaptable to different habitats and therefore it is expected that they will be found at further sites in both Trinidad and Tobago.