Chaleponcus gracilior, Enghoff, 2014

Enghoff, Henrik, 2014, A mountain of millipedes I: An endemic species-group of the genus Chaleponcus Attems, 1914, from the Udzungwa Mountains, Tanzania (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 100, pp. 1-75 : 58-60

Chaleponcus gracilior sp. nov.

urn:lsid:zoobank.org:act:85282955-A517-4E67-8848-F2C3C880DEC6

Figs 4 , 9 , 28

Diagnosis

Slender, but with more podous rings than other small species. Easily recognizable by the subrectangular cucullus profile, by the conspicuous ‘inflated’ distal telomeral process and by the unique ‘string-ofbeads’-like appearance of the limbus. Gonopod coxa ( Fig. 9 ) without a lateral process; metaplical shelfspine short.

Etymology

The name is a Latin adjective meaning “more slender” and refers to the small body diameter in relation to the number of body rings.

Material studied (total: 84 ♂♂)

Holotype

TANZANIA: ♂, Iringa Region, Iringa District, Udzungwa Mts, New Dabaga / Ulangambi FR, 08°05’ 37.9” S, 35°54’ 05.6” E, fallow/cultivation, 1900–1920 m asl, plot FP, casual, 26–28 Nov. 2000, Frontier Tanzania leg. ( ZMUC).

Paratypes

All from TANZANIA, Iringa Region, Iringa District, Udzungwa Mts, New Dabaga/Ulangambi FR, all collected by Frontier Tanzania, all in ZMUC: 1 ♂, 08°05’ 34.5” S, 35°55’ 31.5” E, montane, 1800–1900 m asl, plot 16, casual, 15–16 Nov. 2000; 1 ♂, 08°06’ 47.4” S, 35°56’ 50.4” E, montane, 1800–1955 m asl, plot MS – plot A, 29 Oct. 2000; 2 ♂♂, 08°03’ 39.9” S, 35°54’ 05.6” E, fallow/previously disturbed, 1900 m asl, plot FF, sample 2 of 3, 28 Nov. 2000; 18 ♂♂, 08°05’ 37.9” S, 35°54’ 05.6” E, fallow/ cultivation, 1900–1920 m asl, plot FP, casual, 26–28 Nov. 2000; 3 ♂♂, 08°00’ 26.5” S, 35°56’ 06.1” E, scrub/thicket/bush, 1908 m asl, plot Kinyonga, 19 Oct. 2000; 3 ♂♂, 08°00’ 26.6” S, 35°56’ 06.1” E, montane forest, 1910 m asl, plot Kinyonga, casual, 24 Oct. 2000; 2 ♂♂, 08°03’ 39.9” S, 35°54’ 05.6” E, fallow/previously disturbed, 1915 m asl, plot FF, casual, 27 Nov. 2000; 1 ♂, 08°00’ 26.6” S, 35°56’ 06.1” E, scrub/thicket/bush, 1915 m asl, plot Kinyonga, 18 Oct. 2000; 1 ♂, 08°03’ 43.6” S, 35°53’ 54.2” E, plantation, 1980 m asl, plot pine, sample 1 of 3, 13 Oct. 2000.

Referred non-type material

TANZANIA: 47 ♂♂, Iringa Region, Iringa District, West Kilombero Scarp FR, 07°45’ 34.2” S, 36°26’ 37.4” E, (open) woodland, 1510 m asl, plot Acacia, casual, 5–8 Dec. 2000, Frontier Tanzania UMPS leg. (ZMUC); 1 ♂, Udzungwa Mts, 1500 m, Kiranzi-Kitungulu FR, 08°09’S, 35°05’E, forest, Jan. 1996, M. Andersen, P. Gravlund, A. Jakobsen leg. (ZMUC); 3 ♂♂, Iringa Region, Iringa District, Kalimbazi Mtn, 2000–2100 m asl, 10 km S of Mazombe, forest floor, Jan Kielland leg. (VMNH).

Type locality

TANZANIA: Iringa Region, Iringa District, New Dabaga/Ulangambi FR, 08°05’ 37.9” S, 35°54’ 05.6” E, fallow/cultivation, 1900–1920 m asl.

Description (male)

DIAMETER. 1.5–1.8 mm, 45–49 podous rings.

COLOUR. After 12 years in alcohol faded, uniform pale brown, no traces of a dorsal stripe.

ANAL VALVES. Each with a long dorsal spine, no ventral spines; marginal rim barely raised, setiferous tubercles inconspicuous.

LIMBUS ( Fig. 4F ). Lobes spatulate, about as long as wide, separated by stretches of straight margin ca. same length as width of lobe; body ring surface between lobes forming shallow concavity behind straight margin; lobes deeply striate on external surface. The unique limbus gives the body ring posterior margins a characteristic ‘string-of-beads’-like appearance, visible even on undissected specimens.

TARSAL SETATION. Normal.

GONOPOD COXA ( Figs 9 , 28 ). About 4 × as long as wide. Lateral margin almost straight, slightly indented at level of proplical lobe (prl) and metaplical shelf (ms), forming a ca. 100° angle with straight apical margin; cucullus (cu) subrectangular. Metaplical flange (mf) ending in a rather sharp 90° angle, no process; metaplical mesal margin shallowly concave up to level of arculus, then abruptly turning mesad at right angles at base of metaplical shelf (ms), then turning apicad at right angles, margin from then on shallowly concave, meeting apical margin under a ca. 80° angle. Metaplical shelf (ms) regularly rounded, projecting posteriad as well as mesad. Metaplical shelf-spine (mss) originating from anteriormesal end of ms, short, directed apicad, slightly and simply curved.

GONOPOD TELOPODITE ( Fig. 28 ). Solenomere with a small proximal side branch (pb) originating on distal surface and consisting of a tiny spine-like part and a larger, irregularly lamellate one. Telomere distally with three branches:

• an anterior, irregularly triangular, twisted lamella (al) with undulate edges,

• a large, smooth, pointed, slightly curved distal process (dp) with an ‘inflated’ appearance,

• an irregularly shaped posterior lamella (pl).

Distribution and habitat

Known from four areas in the Udzungwa Mts: New Dabaga/Ulangambi FR, West Kilombero Scarp FR, Kiranzi-Kitungulu FR and Kalimbazi Mtn. Altitudinal range: 1500–2100 m asl. Habitat: montane forest, fallow/previously disturbed/cultivation, scrub/thicket/bush, plantation, (open) woodland. This species seems much more euryoecious than any other species in the C. dabagaensis group.

Coexisting species

In line with its comparatively wide distribution, C. gracilior sp. nov. co-occurs with many other species of the C. dabagaensis group. Thus, C. dabagaensis was found in the same sample as C. gracilior sp. nov. in Kiranzi-Kitungulu FR, and C. dabagaensis , C. krai sp. nov., C. malleolus sp. nov., C. mwabvui sp. nov., C. netus sp. nov., C. termini sp. nov. and C. vilici sp. nov. were found in the same samples as C. gracilior sp. nov. in New Dabaga/Ulangambi FR. In addition, C. krai sp. nov. also occurs on Kalimbazi Mtn, C. nectarinia sp. nov., C. teres sp. nov., and C. vandenspiegeli sp. nov. also occur in New Dabaga/ Ulangambi FR., and C. basiliscus sp. nov., C. circumvallatus sp. nov., C. ibis sp. nov., C. netus sp. nov., and C. tintin sp. nov. also occur in West Kilombero FR.

Figures

Fig. 4. Limbus types in Chaleponcus species, SEM micrographs, external view, except I: internal view. — A. Lobes pointed, more than twice as long as broad (C. scopus sp. nov.). B. Lobes pointed, slightly less than twice as long as broad (C. howelli sp. nov.). C. Lobes pointed, almost equilateral triangles (C. netus sp. nov.), D. Lobes rounded, slightly longer than broad (C. dabagaensis Kraus, 1958). E. Lobes broadly rounded, slightly shorter than broad (C. hamerae sp. nov.). F. Lobes spatulate (C. gracilior sp. nov.). G. Lobes rounded, broader than long, spinose, ridged (C. krai sp. nov.). H. Lobes ca. 3 times as broad as high, rounded, spinose (C. teres sp. nov.). I. Lobes rounded, much broader than high, smooth (C. malleolus sp. nov.). J. No lobes (C. circumvallatus sp. nov.). Scales: 0.01 mm (A– F, J), 0.001 mm (G–I).

Fig. 9. Chaleponcus spp., outline of coxite of left gonopod, posterior view. (The ’transverse’ plane of the gonopod is usually slightly at angles with the exact transverse plane of the millipede, so it may be necessary to tilt the gonopod slightly in order to obtain the view shown on the drawings.) The stippled lines indicate the place where the telopodital basomere emerges from the coxal cavity. Not to scale.

Fig. 28. Chaleponcus gracilior sp. nov., gonopods. A. Gonopods in situ in body ring 7, anterior view. B. Right gonopod, detail of base of solenomere, showing basal side branch consisting of a tiny, spinelike part and a larger, irregularly lamellate one. C. Right gonopod, anterior-mesal view. D. Left gonopod, posterior view. E. Left telopodite, posterior-lateral view. F. Right telopodite, anterior view. al = anterior telomeral lamella, cu = cucullus, dp = distal telomeral process, mf = metaplical flange, ms = metaplical shelf, mss = metaplical shelf-spine, pb = proximal side branch of solenomere, pl = posterior telomeral lamella, prl = proplical lobe. Scales: 0.1 mm (A, C–F), 0.05 mm (B).