Aquattuor udzungwensis Enghoff, 2015

Enghoff, Henrik, 2020, A mountain of millipedes VIII. The genus Aquattuor Frederiksen, 2013 revisited - a new species from the Udzungwa Mts, Tanzania, another from the Nguru Mts, and introduction of the first pair of male legs as a source of taxonomic characters (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 626, pp. 1-32 : 24-28

Aquattuor udzungwensis Enghoff, 2015

Figs 1 , 2 , 7 D–E, 9, 17–18

Aquattuor udzungwensis Enghoff, in Enghoff & Frederiksen, 2015: 13 .

Diagnosis

Diameter 1.44–1.75 mm, 44–54 podous rings ( Fig. 9 ). Shares a short (as broad as long, or slightly longer) gonopodal palette with A. claudiahempae , A. denticulatus , A. fasciatus , A. stereosathe and A. submajor . Differs from these species by having the telopodite of the first pair of male legs represented by the prefemur only, and by having the basal telomeral lamella forming a subspherical chamber with a spinose, lid-like flap.

Material studied (total: 302 ♂♂, 120 ♀♀)

TANZANIA • 4 ♂♂, paratypes; Iringa Region, Udzungwa Mts, Udzungwa Scarp FR, above Chita Village ; 730 m a.s.l.; 25–29 Oct. 1984; N. Scharff leg.; pitfall traps in lowland rain forest; NHMD 621656 • 16 ♂♂, 13 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 1; 07°41′13.5″ S, 36°56′28.6″ E; 650 m a.s.l.; 24 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from seven traps); NHMD 621657 • 1 ♂, 4 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 2; 07°41′14.9″ S, 36°56′24.7″ E; 650 m a.s.l.; 24 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping; NHMD 621658 • 45 ♂♂, 12 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 3; 07°41′02.4″ S, 36°55′49.3″ E; 1005 m a.s.l.; 14 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from twelve traps); NHMD 621659 • 24 ♂♂, 2 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 4; 07°41′05.2″ S, 36°55′48.4″ E; 993 m a.s.l.; 15 Sep. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from eight traps); NHMD 621660 • 8 ♂♂, 5 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 7; 07°41′23.4″ S, 36°56′00.7″ E; 708 m a.s.l.; 24 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from six traps); NHMD 621661 • 167 ♂♂, 68 ♀♀; Morogoro Region, Udzungwa Mts National Park , Kidatu, Plot 8; 07°41′12.9″ S, 36°55′39.2″ E; 978 m a.s.l.; 14 Oct.2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from eleven traps); NHMD 621662 • 2 ♂♂; Morogoro Region, Udzungwa Mts National Park , Mito Mitatu, Plot 13; 07°50′29.6″ S, 36°52′01.3″ E; 674 m a.s.l.; 26 Oct. 2014; J. Malumbres- Olarte leg.; pitfall trapping (summed catch from two traps); NHMD 621663 • 5 ♂♂, 2 ♀♀; Morogoro Region, Udzungwa Mts National Park , Mito Mitatu, Plot 14; 07°50′26.1″ S, 36°51′33.0″ E; 1006 m a.s.l.; 26 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from four traps); NHMD 621664 • 1 ♂; Morogoro Region, Udzungwa Mts National Park , Mito Mitatu, Plot MM2; 07°50′15.1″ S, 36°50′49.9″ E; 1109 m a.s.l.; T. Pape and N. Scharff leg.; pitfall trapping; NHMD 621665 • 13 ♂♂, 4 ♀♀; Morogoro Region, Udzungwa Scarp Catchment Forest Reserve , Chita, Plot 16; 08°30′13.4″ S, 35°55′08.9″ E; 659 m a.s.l.; 31 Oct. 2014; J. Malumbres-Olarte leg.; pitfall trapping (summed catch from seven traps); NHMD 621666 • 19 ♂♂, 10 ♀♀; Morogoro Region, Udzungwa Scarp Catchment Forest Reserve , Chita, Plot 17; 08°29′58.1″ S, 35°54′59.5″ E; 908 m a.s.l.; 30 Oct. 2014; J. Malumbres- Olarte leg.; pitfall trapping (summed catch from six traps); NHMD 621667 .

Descriptive notes

The newly studied specimens on average have more podous rings than those studied by Enghoff & Frederiksen (2015) ( Fig. 9 ). In particular, the specimens from Kidatu and Mito Mitatu have more podous rings (49–54, most specimens 53), whereas the new specimens from Chita (49–51 podous rings) overlap with the previously studied ones; see also Discussion.

First pair of male legs ( Fig. 7 D–E): prefemoral processes finger-shaped to triangular; telopodital podomeres distal to prefemur missing in all studied specimens; see Discussion.

Gonopod telopodite ( Fig. 17 ): basal telomeral lamella (btl) forming a subspherical chamber with a spinose, lid-like flap, cf. A. submajor and remarks below.

Remarks – The distinction between A. submajor and A. udzungwensis

The distinction between A. udzungwensis and A. submajor according to Enghoff & Frederiksen (2015) is quite subtle. The newly studied material has contributed to a better understanding of the differences between these two species. Among the differences stated by Enghoff & Frederiksen (2015), the shape of the meso-posterior lamella of the telomere seems to be the only reliable one ( Figs 16–17 ). The mesoposterior lamella is high and basally angled in A. udzungwensis , and towards the tip of the telomere, the lamella narrows gradually. In A. submajor , the lamella is lower, not angled, and not narrowing so strongly towards the tip.

However, two new clear differences can now be added:

• The basal telomeral lamella (btl) in A. udzungwensis has a small, spinose, lid-like flap (spl) ( Fig. 17 ); such a flap is absent in A. submajor ( Fig. 16 ).

• In all dissected males of A. udzungwensis (> 10), collected in several parts of the Udzungwa Mts, the telopodites of the first leg-pair are strongly reduced distal to the prefemur ( Fig. 7 D–E). Only tiny, somewhat irregular and darkened remnants are present, suggesting that their absence may be due to some physical damage inflicted on the male. In all examined males of A. submajor , the telopodites are normal ( Fig. 7 A–C).

For both species, the newly studied material considerably widens their size range: newly studied specimens of A. submajor have fewer podous rings and a smaller body diameter than those studied by Enghoff & Frederiksen (2015); in A. udzungwensis the newly studied specimens tend to have more podous rings than those previously studied, while there is a marked difference in diameter. These differences may, at least in part, be correlated with altitude: both species show a clear decrease of numbers of podous rings with increasing altitude from mostly> 50 podous rings at 600–900 m altitude to <46 rings at 1400–1550 m altitude ( Fig. 18 ).

Distribution

Known from several localities in the Udzungwa Mts ( Fig. 1 ). Altitudinal range: 650–1410 m a.s.l.

Figures

Fig. 1. Collecting sites for Aquattuor spp. in the Udzungwa Mts. Based on Marshall et al. (2010: fig. 1); inset by permission of the Eastern Arc Mountains Conservation Endowment Fund.

Fig. 2. Aquattuor udzungwensis Enghoff, 2015, specimens from Chita, heads, lateral view. A. Male (NHMD 621667). B. Female (NHMD 621667). Scale bars = 0.1 mm. The arrow points at the distoventral stipital expansion lobe in the male.

Fig. 7. Aquattuor spp., first pair of male legs. A–C. A. submajor Enghoff, 2015, paratype, ♂ (NHMD 621651). A. Anterior view. B. Sublateral view. C. Ventral view. D–E. A. udzungwensis Enghoff, 2015, male from Udzungwa Mts National Park, Kidatu (NHMD 621662). D. Anterior view. E. Ventral view. Scale bars = 0.1 mm.

Fig. 9. Aquattuor spp. Body size (number of podous rings and midbody vertical diameter) in males of Aquattuor species from the Udzungwa Mts, and of A. claudiahempae Enghoff & Frederiksen, 2015 from Mt Kilimanjaro. In case of (almost) coinciding values, symbols have been slightly displaced horizontally.

Fig. 17. Aquattuor udzungwensis Enghoff, 2015, male from Udzungwa Mts National Park, Kidatu (NHMD 621659), left gonopod telopodite. A. (Meso-)posterior view. B. Basal telomeral lamella, distal (ventral) view. C. Telomere, sublateral view. Abbreviations: btl = basal telomeral lamella; mpl = mesoposterior telomeral lamella, the arrow points to the diagnostic angle; slm = solenomere; spl = spinose lid-like flap; tm = telomere. Scale bars = 0.05 mm.

Fig.16. Aquattuor submajor Enghoff, 2015. A–D. Male from Udzungwa Mts National Park, Kidatu (NHMD 621653), left gonopod telopodite. A. Posterior view. B. Anterior view. C. Distal (ventral) view. D. Basal (dorsal) view. E–F. Male from Udzungwa Mts National Park, Kidatu (NHMD 621654), right gonopod telopodite, broken into two pieces. E. Basal part. F. Tip of telomere. Abbreviations: btl = basal telomeral lamella; mpl = meso-posterior telomeral lamella; slm = solenomere; tm = telomere. Scale bars: A–E = 0.1 mm; F = 0.02 mm.

Fig. 18. Aquattuor submajor Enghoff, 2015 and A. udzungwensis Enghoff, 2015; numbers of podous rings as a function of altitude.