Xystopyge proplicatus Frederiksen & Enghoff, 2012

Enghoff, Henrik, 2022, Mountains of millipedes. The family Odontopygidae in the Eastern Arc Mountains of Tanzania (Diplopoda, Spirostreptida), European Journal of Taxonomy 803, pp. 1-136 : 121-124

Xystopyge proplicatus Frederiksen & Enghoff, 2012

Figs 73–74

New Material examined (total 2 ♂♂)

TANZANIA • 2 ♂♂; Morogoro Region, Morogoro District, Kasanga FR ; 37°45′ E, 7°10′ S, 700– 900 m a.s.l.; 27 Jul.–2. Aug. 2000; lowland submontane forest, taken from leaf litter and rotting logs; Nike Doggart leg., Uluguru Mountains Biodiversity Conservation Project; NHMD 621774 • 1 ♂; Morogoro Region, Morogoro District; Ruvu FR ; 37°49′–37°54′ E, 6°53′–7°02′ S; 200–400 m a.s.l.; Sep. 2000; lowland forest; Nike Doggart leg., Uluguru Mountains Biodiversity Conservation Project; NHMD 621775 .

Descriptive notes based on new material

SIZE. Length ca 55 mm, diameter 3.2–3.4 mm, 57–59 podous rings, no apodous rings in front of telson.

COLOUR. After 20 years in alcohol faded to straw yellow; traces of dorsal pale stripe still visible.

SUPRALABRAL SETAE. 4–5.

MANDIBULAR STIPES. With large disto-ventral lobe, distal margin very shallowly concave.

ANAL VALVES. With a distinct dorsal spine, no ventral spine; margin raised, with 2 sessile setae.

LIMBUS ( Fig. 73E ). Margin with smooth rounded, finger-shaped lobes.

LEGS. Ventral pads on postfemur and tibia from leg-pair 4 till the last.

FIRST PAIR OF LEGS ( Fig. 73A–C ). Prefemoral lobes short, rounded-triangular in ventral view. Three to five long coxosternal setae (CXS) adjacent to lateral side of prefemoral process; prefemur with two mesapical setae (APS) and five to six peglike lateral sensilla (LPS).

GONOPOD STERNUM (STERNUM 8) ( Fig. 73J , drawing, gonopod sternum of specimen prepared for SEM lost). Slender, parallel-sided, apically emarginated, closely appressed to long processes from the very well-developed metaplical flange.

STERNUM 9 ( Fig. 73D ). Broader than long, pentagonal.

GONOPOD COXA ( Fig. 73F–I ). Rather compact. Proplica (PP) longer than metaplica, distally with two rounded processes (ppr1, ppr2) of which ppr1 may correspond to the proplical lobe (PPL) seen in other odontopygids; a long spine (pps) behind the two ppr processes. Metaplica (MP) massive, posterior margin expanded into large ‘hump’ (mph) delimiting large concavity on posterior-lateral surface of coxa; metaplica anterio-distally prolonged into short ‘snout’ (mps).

GONOPOD TELOPODITE ( Fig. 74 ). Arculus 135°. Torsotope (TT) not very well-delimited. Solenomere (SLM) as long as telomere, at rest nesting in hollow inner surface of the latter (partly free from telomere

on Fig. 74 due to preparation); Basal ¾ of solenomere slender with a subcircular cross section; with a small basal spine (BSS) a short distance from basis, distally expanded and divided into a lamellate, strongly fluted, pointed lobe (sdl) and an smooth process (sdp) ending in two slender spines of unequal length. Telomere (TM) overall consisting of a ribbon describing a full circle and at the same time folded lengthwise forming a concavity along the inner side of the circle; a spinelike process (tsp) closely appressed to outer surface of telomere ca ⅓ from its basis, no processes along inner perimeter; distal ¼ of telomere bent posteriad, expanded and with several irregular lamellae, including a small, unilaterally dentate lamella (tdl); interior surface of telomere at least partly microspiculate ( Fig. 74F ).

Distribution and habitat

Previously reported from Morogoro Region, Morogoro Rural Distr., Uluguru Mts, Kimboza Forest; 250 m a.s.l. ( Frederiksen & Enghoff 2012). Now known from three forest reserves in the Uluguru Mts. In Kasanga FR taken from leaf litter and rotting logs in lowland and lowland submontane forest.

Remarks

Found in the same sample as the holotype of X. doggartae sp. nov. The newly studied specimens closely agree with the original description of X. proplicatus , with one notable exception: Frederiksen & Enghoff (2012: fig. 8: ass1 and ass2) described the solenomere tip in X. proplicatus as having two consecutive spines, whereas a SEM examination of one of the new specimens showed that these spines are in fact tines originating from one common stem (sdp). However, reexamination revealed that this also applies to the holotype of X. proplicatus (NHMD: ZMUC00020498).

The near-juxtaposition of the fluted solenomeral lobe (sdl) and the mirospiculate inner surface of the telomere (also seen in X. doggartae sp. nov.) suggests that these structures may play a role in sperm transfer and/or in sperm competition (cf. Barnett & Telford 1996).

Figures

Fig. 73. Xystopyge proplicatus Frederiksen & Enghoff, 2012, specimen from Kasanga (NHMD 621774). A–C. First pair of legs. A. Sublateral view. B. Anterior view. C. Ventral view. D. Sternum 9. E. Midbody dorsal limbus. F–I. Left gonopod coxa. F. Anterior view. G. Mesal view. H. Posterior view. I. Lateral view. J. Gonopod sternum. Abbreviations: APS=mesapical prefemoral setae; CXS =coxosternal setae; LPS =lateral prefemoral sensilla; MP=metaplica; MPF =metaplical flange; mph= metaplical ‘hump’; mps= metaplical ‘snout’; PP =proplica; ppr1, ppr2 = proplical processes; pps=proplical spine. Scale bars: A–D, F–J =0.2 mm; E= 0.01 mm.

Fig. 74. Xystopyge proplicatus Frederiksen & Enghoff, 2012, specimen from Kasanga (NHMD 621774). A. (Dorso-)anterior view. B. (Ventro-)posterior view. C. Ventral view. D. Mesal view. E. Tip of solenomere, solenomeral distal lobe (sdl) highlighted in green.F. Close-up of fluted areas of solenomeral distal lobe and microspiculate inner surface of telomere. Abbreviations: BSS= basal solenomeral spine; sdl = soloenomeral distal lobe; sdp =solenomeral distal process; SLM =solenomere; TM = telomere; tsp = telomeral spinelike process. Scale bars: A–B =0.2 mm; C–D =0.1 mm; E= 0.005 mm; F =0.02 mm.