Prionopetalum asperginis, Henrik Enghoff, 2016

Henrik Enghoff, 2016, A mountain of millipedes IV: Species of Prionopetalum Attems, 1909, from the Udzungwa Mountains, Tanzania. With notes on “ P. ” fasciatum (Attems, 1896) and a revised species key (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 215, pp. 1-23 : 6-9

Prionopetalum asperginis sp. nov.

urn:lsid:zoobank.org:act:FE9E9 A 13-4D50-40E9-8B6D-3D40AEA0E1 A 2

Figs 3–4 , 9 W, 10D, 11K

Diagnosis

Differs from congeners by the combination of a laterally smooth gonopod coxa, a pointed apical mesad metaplical process subtended by a rounded mesad lobe, a simple, fingerlike proximal telomere process and a simple distal telomere process without secondary branches.

Etymology

The species is named after the recently discovered Kihansi spray toad, Nectophrynoides asperginis Poynton, Howell, Clarke & Lovett, 1999 ; see “Distribution and habitat”.

Material studied (total: 15 ♂♂)

Holotype

TANZANIA: ♂ Udzungwa Mts , Kihansi, 8°24' S, 36°21' E, “forest site”, Jun.–Aug. 1997, I. Zilihona leg. ( ZMUC).

Paratypes

TANZANIA: 12 ♂♂, same data as holotype ( ZMUC) ; 1 ♂ Iringa Region, Mufindi District, Udzungwa Scarp Forest Reserve , 8°31.58' S, 35°53.91' E, 750 m asl, 5–12 Mar. 1996, GUV28-2, Proj. S.H. McKamey et al. leg. ( ZMUC) ; 1 ♂ Morogoro Region, Kilombero District, Lower Kihansi Project, Udagaji Gorge , 7 Nov. 1997, Jan Kielland leg. ( VMNH) .

Type locality

TANZANIA: Udzungwa Mts , Kihansi, 8°24' S, 36°21' E.

Description

SIZE. Length c. 6½ cm, diameter 4.4–4.9 mm, 60–65 podous rings, no apodous rings in front of telson.

COLOUR. After 18 years in alcohol almost uniform light brown. No lighter dorsal markings.

ANAL VALVES ( Fig. 3 A–B). Each with a long, pointed dorsal spine, no ventral spine, marginal rim raised, with 3 setae on very poorly demarcated tubercles.

LIMBUS ( Fig. 3 C). With triangular, almost equilateral, pointed lobes, external surface of lobes densely striate.

MALE LEGS. Postfemora and tibiae with large, soft pads, except on first four to five and several posteriormost leg pairs.

GONOPOD COXA ( Fig. 3 D–F). Lateral margin almost straight, entirely smooth. Mesal margin of proplica straight, proplical lobe (prl) in anterior view almost hidden behind apical expansion of metaplica. Basal part of metaplica with large longitudinal mesad flange (mlf), separated by a deep sinus from an obliquehorizontal, sub-semicircular mesad flange (mof), apical part of metaplica expanded anteriad, forming a pointed process (amp) covering proplical lobe, a rounded mesad lobe (mml) and a slender disto-mesad process (mmp).

GONOPOD TELOPODITE ( Fig. 4 ). A well-developed post-torsal spine (“femoral spine”, pts) just before posttorsal narrowing (broken on illustrated specimen). Solenomere (slm) simple, slender. Telomere with a large, proximal lobe (pxl) and a rough area (ra) on apical surface, further distally divided into two processes. Proximal telomere process (tpp) parallel-sided, apically rounded. Distal telomere process (tdp) only slightly broader than solenomere, apically with one margin denticulate ( Fig. 4 F).

Distribution and habitat

Known only from the southern part of the Udzungwa Mts, Udzungwa Scarp Forest Reserve and the Kihansi area. The latter area has become famous because of the Kihansi spray toad, Nectophrynoides asperginis Poynton, Howell, Clarke & Lovett, 1999 , which occurred in the Kihansi area but is now regarded as extinct in the wild although a reintroduction programme was started in 2013 (IUCN SSC Amphibian Specialist Group 2015). Zilihona et al. (1998) described in detail the area where I. Zilihona collected her specimens. Altitudinal range 550–750 m asl (cf. Zilihona et al. 1998).

Coexisting species

The sample collected by I. Zilihona also contains another, much smaller odontopygid which will be described in a forthcoming paper.

Remarks

Fig. 3G shows a transverse section (= break) of the basal part (basomere, ba) of the gonopod telopodite. The picture clearly shows how the canal (eg) that continues to the tip of the solenomere is formed as a groove near the surface. This canal has been supposed to be a sperm canal (“Samenrinne” of Kraus 1966, e.g., his figs 28–29), but considering that nothing is known about its function, the neutral term “efferent groove” is preferable (cf. Enghoff 2011). There is also what looks like an entirely internal canal (ic) which is accompanied by dense bundles of tubuli, probably tracheae (Fig. 3H), similar to those recently described by Reboleira et al. (2015) from the base of the vulva of a cambalid millipede. The extent and function of this canal is unknown.

Figures

Fig. 3. Prionopetalum asperginis sp. nov., paratype from Kihansi, “ forest site ”. A – B. Hind end. A. Lateral view. B. Posterior view. C. Limbus. D – F. Right gonopod coxa. D. Anterior view (light blue: mounting tape). E. Mesal view. F. Posterior view. G. Transverse section of right gonopod basomere (circle: bundle of tracheae). H. Cluster of tracheae next to internal canal. Abbreviations: amp = anterior metaplical process; eg = efferent groove; ic = internal canal; mlf = metaplical longitudinal flange; mml = metaplical mesad lobe; mmp = distomesal metaplical process; mof = metaplical oblique / horizontal flange; prl = proplical lobe. Scale bars: A, B, D – F = 0.1 mm; C, H = 0.001 mm; G = 0.01 mm.

Fig. 4. Prionopetalum asperginis sp. nov., paratype from Kihansi, “ forest site ”, right gonopod telopodite. A. Anterior and slightly mesal view. B. Posterior view. C. Basal view. D. Apical view. E. Apical-mesal view. F. Mesal and slightly posterior view. Abbreviations: ba = basomere; pts = post-torsal spine (broken); pxl = proximal lobe of telomere; ra = rough area of telomere; slm = solenomere; tdp = distal process of telomere; tpp = proximal process of telomere. Scale bars = 0.1 mm.

Fig. 9. Prionopetalum spp., outlines of distal part of gonopod coxa. The species appear in the sequence in which they key out in the identification key. A. P. megalacanthum (after a specimen in NHMW). B. P. frundsbergi (based on Kraus 1960). C. P. bifidum (based on VandenSpiegel & Pierrard 2009). D. P. tricuspis (based on Brolemann 1920). E. P. aculeatum (based on Kraus 1960). F. P. ndelei (based on VandenSpiegel & Pierrard 2009). G. P. serratum (based on Kraus 1960). H. P. dentigerum (based on Kraus 1960). I. P. tanganjikum (based on Kraus 1960). J. P. xerophilum (based on Kraus 1960). K. P. clarum (based on Kraus 1960). L. P. pulchellum (based on Kraus 1960). M. P. etiennei (based on Demange 1982). N. P. lindi (based on VandenSpiegel & Pierrard 2009). O. P. coronatum (based on Kraus 1958). P. P. exaratum (based on Kraus 1960). Q. P. cornutum (based on Kraus 1960). R. P. kraepelini (orig.). S. P. glomeratum (based on Attems 1935). T. P. urbicolum (based on Kraus 1960). U. P. suave (based on Kraus 1960). V. P. fryeri (based on Kraus 1960). W. P. asperginis sp. nov. (orig). Not to scale.