Aquattuor Frederiksen, 2013

Enghoff, Henrik & Frederiksen, Sara B., 2015, A mountain of millipedes II: The genus Aquattuor Frederiksen, 2013 - five new species from the Udzungwa Mountains and one from Mt. Kilimanjaro, Tanzania (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 150, pp. 1-25 : 3-7

Genus Aquattuor Frederiksen, 2013

This genus was established by Frederiksen (2013b) for the type and until now only species, A. denticulatus (East Usambara Mts, Tanzania). The name is regarded as a masculine noun.

Diagnosis

A genus of Odontopygidae Prionopetalini in which the gonopodal proplica is apically expanded into a distal ‘palette’, the metaplica has an oblique flange, the solenomere is simple, thin and whiplike, the telomere terminates in a long, curved gutter-like to tubular part, and the limbus of the body rings consists of large, rectangular, easily detached flaps.

Etymology

The genus owes its name to the unique limbus flaps which resemble tiny sheets of paper in the standard A4 format.

Description

This description only applies to males and, as far as non-gonopodal characters are concerned, only includes a selection.

Non-gonopodal characters

BODY LENGTH. 19–35 mm. Midbody vertical diameter 1.4–2.1 mm. 44–54 podous rings, no apodous rings in front of telson. See Fig. 2.

COLOUR. Colours of specimens from Udzungwa and East Usambara Mountains all partly or completely faded, leaving only newly collected specimens from Mt. Kilimanjaro with fresh colour ( Fig. 1 ). Light mid-dorsal longitudinal stripe or traces thereof sometimes present, even on faded specimens.

LIMBUS. Consisting of relatively large (c. 0.04 × 0.06 mm) rectangular flaps which are easily detached ( Fig. 3 D–E).

TELSON ( Fig. 3 B–C). Preanal ring with wrinkled/coriaceous sculpture dorsally. Anal valves with wrinkled/coriaceous sculpture, with a pronounced dorsal denticle and a smaller ventral one, denticles well set off from rest of valve rather than just being “sharp corners”. Each valve with three setae. Free margin (“lip”) of anal valves raised and provided with three small tubercles on which the setae are borne. Gonopods (see Fig. 4 )

COXA. In anterior or posterior view 3½–4½ × as long as broad. Margins of proplica (pp) parallel or slightly diverging in basal c. ⅔, apical c. ⅓ set off by mesal (mi) and lateral (li) incisions; apical part of proplica appearing like a rounded “palette” (pa). Proplical lobe (prl) protruding into mesal incision. Metaplica (mp) with irregular surface; at level of mesal and lateral incisions a stout ridge (mpr) running obliquely across metaplica.

TELOPODITE. Basomere (ba) with small spine (bs) just distal of torsotope ( Fig. 11A, C ), arculus 90°. Posttorsal narrowing (pn) pronounced (e.g., Figs 5A , 6A ). Telopodite beyond pn divided into solenomere (slm) and telomere (tm).

SOLENOMERE. Long, thin, whiplike, often resting within telomeral gutter but on preserved specimens frequently free (probably an artefact), apical part with oblique-longitudinal flutings.

TELOMERE. At base expanded into a complicated basal telomeral lamella (btl) obscuring origin of solenomere ( Fig. 5D ). Main part of telomere consisting of a long, narrow lamella folded into a more or less narrow gutter, sometimes even tube-like in distalmost part; gutter/tube describing a 90°–360° curve, usually in almost one plane, but sometimes ( A. stereosathe Enghoff sp. nov.) clearly in three dimensions (note: this applies to preserved specimens). Posterior margin of gutter expanded into mesal-posterior lamella (mpl) (e.g., Fig. 5D ). Tip of telomere variable: margins smooth or denticulate-laciniate, internal surface of gutter more or less microspiculate (e.g., Fig. 6 C–D).

Distribution

Species of Aquattuor are so far known only from Tanzania. They have been found in several mountain blocks belonging to the Eastern Arc Mts ( Burgess et al. 2007): Udzungwa (5 species), Nguru (1 species), Rubeho (1 species) and East Usambara (1 species). One further species has been found on Mt. Kilimanjaro. For an overview, see Figs 12–13 .

Intercalary cuticular microscutes

In A. submajor Enghoff sp. nov. and A. udzungwensis Enghoff sp. nov., intercalary cuticular microscutes, similar to those first reported by Akkari & Enghoff (2011) in polydesmidan millipedes and subsequently found, inter alia, in the odontopygid genus Chaleponcus Attems, 1914 ( Enghoff 2014) and the callipodidan genus Lusitanipus Mauriès, 1978 ( Reboleira & Enghoff 2015), were observed.

Notes on identification

The species of Aquattuor are all quite similar, even in gonopod structure. In this respect, they form a contrast to the previously treated (much larger) species-swarm centred in the Udzungwa Mts., i.e., the Chaleponcus dabagaensis -group ( Enghoff 2014), in which gonopods are highly diverse. Differences between Aquattuor species concern body size ( Fig. 2 ), details of the outline of the gonopod coxa, the curvature of the telomere, the development of the posterior margin of the telomere, and the armature of the telomere tip.

Similar genera

By far the most diagnostic character of Aquattuor is the large (sub)rectangular-lobed limbus. Subrectangular limbus lobes do occur in certain other odontopygid genera, e.g., Allantogonus Attems, 1912 ( Kraus 1960: fig. 5) and Syndesmogenus Attems, 1909 ( Kraus 1966: figs 97–99), but in these genera, the lobes are much smaller and are not prone to detachment. The gonopods of Aquattuor , with their long, whip-like solenomere and slender telomere, superficially resemble those of Allantogonus ( Kraus 1960: figs 7, 11, 17) and Lamelloramus Frederiksen, 2013 (Frederiksen 2013: figs 5, 9). However, the coxal apex in Allantogonus is folded basad over the anterior side; the metaplical flange of Lamelloramus is situated completely differently on the median side, and the telomere is either strongly curling up or looping in these genera. The limbus is completely different from that of Aquattuor in both.

Included species (alphabetically)

Aquattuor claudiahempae Enghoff & Frederiksen sp. nov.

A. denticulatus Frederiksen, 2013 (type species)

A. longipala Enghoff sp. nov.

A. major Enghoff sp. nov.

A. stereosathe Enghoff sp. nov.

A. submajor Enghoff sp. nov.

A. udzungwensis Enghoff sp. nov.

Figures

Fig. 2. Body size (numbers of podous rings and midbody vertical diameter) in ♂♂ of species of Aquattuor Frederiksen, 2013. In cases of (almost) coinciding values, symbols have been slightly displaced horizontally.

Fig. 1. Aquattuor claudiahempae sp. nov., two paratype ♂♂ after 18 months in alcohol. Scale bar = 1 mm (B). Photographs by S. Reboleira.

Fig. 3. Aquattuor spp. A. A. stereosathe Enghoff sp. nov., paratype, front end. B–C. A. udzungwensis Enghoff sp. nov., paratype, telson, lateral and posterior view. D–E. A. udzungwensis Enghoff sp. nov., limbus. D. Specimen from West Kilombero Scarp FR. E. Paratype. Scale bars: A–D = 0.1 mm; E = 0.01 mm.

Fig. 4. Aquattuor submajor Enghoff sp. nov., paratype. A. Gonopods in situ, right gonopod coloured. B. Left gonopod coxa and basal part of telopodite. C. Left gonopod telopodite and part of coxa, dorsal (basal) view.Articifical colours: orange = coxa; blue = basomere; yellow = solenomere; pink = telomere; red = gonopod sternum; light green = ventral part of eighth pleurotergite (right side); dark green = sternum of reduced ninth leg-pair. mp = metaplica; pa = palette; pp = proplica. Scale bars = 0.1 mm.

Fig. 11. Aquattuor denticulatus Frederiksen, 2013, paratype. A. Gonopods, posterior view. B. Telomere, distal part, lateral view. C. Gonopods, anterior view. D. Telomere tip. li = lateral incision; bs = basomeral spine; pa = palette; mpl = mesal-posterior lamella of telomere. Scale bars: A, C = 0.1 mm; B = 0.02 mm; D = 0.01 mm.

Fig. 5. Aquattuor submajor Enghoff sp. nov., paratype, left gonopod. A. Anterior view. B. Close-up of mesal incision. C. Tip of telomere. D. Posterior view. btl = basal telomeral lamella; li = lateral incision; mi = mesal incision; mpl = mesal-posterior lamella of telomere; pa = palette; pn = posttorsal narrowing. Scale bars: A, D = 0.1 mm; B–C = 0.01 mm.

Fig. 6. Aquattuor major Enghoff sp. nov., paratype. A. Left gonopod, anterior view. B. Left gonopod, posterior view. C–D. Telomere tip, two different views. li = lateral incision; pa = palette; mpl = mesal posterior lamella of telomere; pn = posttorsal narrowing; tt = triangular tooth of telomere. Scale bars: A–B = 0.1 mm; C–D = 0.01 mm.

Fig. 12. Map of part of Tanzania showing the mountains where Aquattuor species have been found. Based on Burgess et al. (2007: fig. 1).

Fig. 13. Map of the Udzungwa Mts showing the forest reserves where Aquattuor species have been found, and the epithets of the species found. Based on Marshall et al. (2010: fig. 1).