Prionopetalum Attems, 1909

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 : 3-6

Genus Prionopetalum Attems, 1909

Prionopetalum Attems, 1909: 51 .

Type species: Prionopetalum serratum Attems, 1909 , by original designation.

Unlike many other genera of Odontopygidae , Prionopetalum is well-defined and quite homogeneous, not only in non-sexual characters, but also in gonopod structure.

Diagnosis

(Modified after Kraus 1960 and VandenSpiegel & Pierrard 2009, excluding some non-gonopodal characters which were mentioned by these authors but which are of no diagnostic value.)

Prionopetalini in which the anal valves have a raised rim, a well-developed dorsal spine and sometimes a smaller ventral one; limbus with simple, pointed denticles (true of all species after removal of “ P.” fasciatum , see below).Male legs with ventral soft pads on postfemur and tibia, except on anteriormost and posteriormost legs (true of all species after removal of “ P.” fasciatum , see below).

GONOPODS. Coxal metaplica on its basal part with a large longitudinal mesad flange (mlf), separated by a deep sinus from an oblique-horizontal sub-semicircular mesad flange (mof). Telopodite with a posttorsal (“femoral”) spine (pts), but without a (“tibial”) spine near the origin of the solenomere, divided into solenomere and telomere shortly after post-torsal narrowing. Solenomere (slm) simple, whip-like, without outgrowths (exception: P. fryeri ( Turk, 1956) with a short accessory branch at c. ⅔ of the solenomere’s length). Telomere with two characteristic processes: a variously shaped, often speciesspecific proximal process (tpp) which projects at ± right angles from the main telomere axis, and a long, slender distal process (tdp) which is armed with a row of spines or thorns. ( In the terminology of Kraus (1960), tpp is “eine hornartige Spitze oder auch eine entsprechende, schalige Lamelle ”, and tdp is “der meist auffallende schlankere Distalabschnitt ….. gezackt oder bezahnt”. For VandenSpiegel & Pierrard (2009), tpp is a “processus basal du tarse”.)

Body size

Published body diameters for adult males range from 2.5 mm ( P. exaratum , P. glomeratum ) to 6.8 mm ( P. bifidum ), but a male of P. frundsbergi in the ZMUC collection has a diameter of 7.6 mm. Published numbers of podous rings range from 57 ( P. exaratum ) to 71 ( P. bifidum ), but the above-mentioned male of P. frundsbergi has 72 podous rings. Table 1 and Fig. 2 summarise the size information and give detailed information for the two Udzungwa species. One has been subtracted from published “segment” numbers because these have traditionally included the telson. Two records have been omitted: “nearly fourty-three” for P. clarum ( Chamberlin, 1927) and 93 for P. tanganjikum Verhoeff, 1941 – the latter number is probably a lapsus calami.

Included species

P. aculeatum Attems, 1914 – Somalia, Kenya P. asperginis sp. nov. – Tanzania

P. bifidum VandenSpiegel & Pierrard, 2009 – Tanzania P. clarum ( Chamberlin, 1927) – D.R. Congo P. cornutum Kraus, 1958 – D.R. Congo

P. coronatum Kraus, 1958 – D.R. Congo

P. dentigerum Verhoeff, 1941 – Tanzania, Rwanda P. etiennei Demange, 1982 – Gambia, Guinée-Bissau, Sénégal P. exaratum ( Attems, 1938) – D.R. Congo

P. frundsbergi (Attems, 1927) – Kenya, Tanzania P. fryeri ( Turk, 1956) – Malawi, Zambia

P. glomeratum Attems, 1935 – D.R. Congo

P. kraepelini ( Attems, 1896) – Tanzania

P. lindi VandenSpiegel & Pierrard, 2009 – Tanzania P. megalacanthum Attems, 1912 – D.R. Congo, Rwanda P. ndelei VandenSpiegel & Pierrard, 2009 – Central African Republic P. pulchellum Kraus, 1960 – Mozambique

P. serratum Attems, 1909 – Kenya, Tanzania P. suave (Gerstäcker, 1873) – Tanzania

P. tanganjikum Verhoeff, 1941 – Tanzania

P. tricuspis Brolemann, 1920 – Kenya

P. urbicolum ( Carl, 1909) – Tanzania

P. xerophilum ( Carl, 1909) – Rwanda, Tanzania

Figures

Fig. 2. Body size (body diameter / number of podous rings) of ♂♂ of Prionopetalum spp. Based on original measurements and data from the literature (see Table 1). For “ other spp. ” the entries are median values of the intervals in Table 1. The report of “ 93 (1) Rumpfringen ” (corresponding to 92 podous rings) for P. tanganjikum by Verhoeff (1941) has been omitted, as has Chamberlin’s (1927) “ nearly fourtythree ” segments for P. clarum; both are regarded as quite unlikely and are probably erroneous.

Tables

Table 1. Numbers of podous rings and body diameter of adult males of species of Prionopetalum. One has been subtracted from published “segment” numbers because these include the telson. None of the species are known to have apodous rings between the last podous ring and the telson.

	No. of podous rings	Diameter (mm)	Source
P. aculeatum	66	5	Attems 1914
P. asperginis sp. nov.	60–65	4.4–4.9	this study
P. bifidum	68–71	5.6–6.8	VandenSpiegel & Pierrard 2009
P. clarum	“nearly fourty-three”	5.5	Chamberlin 1927
P. cornutum	63	3	Kraus 1958
P. coronatum	58	3.7	Kraus 1958
P. dentigerum	65	6.0	this study1
P. etiennei	60	2.5	this study2
P. exaratum	57	2.5	Attems 1938
P. frundsbergi	72	7.6	this study3
P. fryeri	65	6	Turk 1956
P. glomeratum	58	2.5	Attems 1935
P. kraepelini	61–65	3.2–3.6	Attems 1896; this study
P. lindi	58–59	3.3–3.8	VandenSpiegel & Pierrard 2009
P. megalacanthum	62	4.3	Attems 1912
P. ndelei	61–63	4.2	VandenSpiegel & Pierrard 2009
P. pulchellum	64	3.0	Kraus 1960
P. serratum	62–66	5.6	Attems 1909
P. suave	62	5	Attems 1896
P. tanganjikum	92	?	Verhoeff 1941
P. tricuspis	65	5.5	Brolemann 1920
P. urbicolum	61–64	4.5	Carl 1909
P. xerophilum	c. 60	4.5	Carl 1909