Morogorius Verhoeff, 1941

Enghoff, Henrik, Ngute, Alain Senghor K., Mnendendo, Hamidu R., Kivambe, Exaud E., Mhagawale, Waziri, Malanda, Robin C., Mpoto, Athuman & Marshall, Andrew R., 2025, A mountain of millipedes XII. The Chelodesmidae of the Udzungwa Mountains, Tanzania (Diplopoda, Polydesmida), European Journal of Taxonomy 997, pp. 210-255 : 214-218

Genus Morogorius Verhoeff, 1941

Morogorius Verhoeff, 1941: 249 .

Type species

Morogorius pallidus Verhoeff, 1941 ( Tanzania) by monotypy.

Other included species

Morogorius divisus Enghoff sp. nov.

Morogorius louishanseni Enghoff sp. nov.

Morogorius pugio Enghoff sp. nov.

Morogorius kitungulu Enghoff sp. nov.

Morogorius cochlear Enghoff sp. nov.

History and diagnosis

The history of Morogorius is brief. In the original description, it was placed in subfamily Cordyloporinae Brölemann, 1916 (now: Prepodesminae ) and was diagnosed as follows (translated from Verhoeff 1941: 249): “This genus is based on the absence of dorsal processes, on lack of denticulation on the paranota as well as on the hind margin of the diplosomites between paranota and sterna, and on characters of the gonopods” and “Different from the related genera Cordyloporus , Paracordyloporus , Scolopopleura and Graphidochirus in the gonopods, in part also in body characters” ( Verhoeff 1941: 249–250). Chamberlin (1952) didn’t mention Morogorius , nor did Demange & Mauriès (1975). Hoffman (1977) restudied and re-drew the gonopods of the type species and compared it to his Tanzaniella howelli Hoffman, 1977 . That’s all.

A useful differential diagnosis of Morogorius is thus not available, as is the case for very many millipede genera. Considering the very large number of genera in Chelodesmidae , in combination with the lack of useful diagnoses of the family Chelodesmidae and the subfamily Prepodesminae , such a diagnosis cannot be presented here. However, Morogorius differs from other Tanzanian genera of Chelodesmidae in the characters presented in Table 2 . The homology of the largest gonopodal process in Morphotelus and Mesodesmus is uncertain, therefore the process may preliminary be termed “solenophore”.

General description of Morogorius (males)

SIZE. Length 21–31 mm, max. width 3.6–5.7 mm. Collum wider than head but narrower than ring 2, roughly parallel-sided from ring 3 to midbody, thereafter moderately tapering.

COLOUR. Overall colour (reddish) brown, in part (species-specific) with some or all paranota contrastingly pale ( Fig. 2A–B ).

HEAD ( Fig. 3A–B ). Densely setose below and between antennal sockets, labrogenal offset not very pronounced, epicranial groove distinct, interantennal space narrow, 0.5–0.6 × length of antennomere 2. Antennae reaching back to ring 6 when stretched.

COLLUM ( Fig. 3A, C ). In the shape of an isosceles curved trapezoid with the longer margin anteriorly, lateral corners smoothly rounded, surface granular, especially laterally. A row of 2–4 setae close to anterior margin.

BODY RINGS ( Figs 3C–H , 7 , 10B–F ). Prozonites smooth, with simple, cellular microsculpture ( Fig. 3D ). Metazonites flat, granular dorsally and laterally, 1.4–1.8 × as broad as prozonites, with 1+1 small, thin setae anteriorly (setae apparently absent in M. pugio Enghoff sp. nov.) and a prominent transverse sulcus on rings 5–18. Paranota horizontal, those of rings 2–3 very slightly projecting forwards, following paranota rectangular but from some point (ring 5–15 according to species) with posterior corners increasingly projecting backward. Paranotal microsculpture ( Fig. 10D ) formed by longitudinally stretched, narrow cytoscutes of more or less irregular shape. Ozopore formula normal (5, 7, 9–10, 12– 13, 15–19), ozopores circular, delimited by smooth ring in peritremata on edge of paranota, ca midway between anterior and posterior margin. Sterna ( Fig. 4E ) broad, with a transverse impression and a row of fine setae near anterior margin. Spiracles (only studied in M. divisus Enghoff sp. nov.): anterior spiracle on each diploring pear-shaped, posterior spiracle subcircular, both with plugs showing a very pronounced cellular pattern ( Fig. 3G ). Limbus ( Fig. 4F ) with straight margin, consisting of a densely, finely striate marginal zone preceded by a row of rectangular cells.

LEGS ( Figs 4C–D , 10F ). Slender, without modifications, length 1.2–1.6 × maximum body width, length not increasing towards hind end,

TELSON ( Fig. 4A–B ). Preanal ring with several setae along dorsal part of posterior margin; epiproct large, with prominent lateral setiferous tubercles; spinnerets arranged in an almost quadratic trapezoid on a smooth terminal swelling, simple, flanked by 1+1 globular, sometimes partly collapsed structures. Anal valves (paraprocts, pp) unmodified, each with 2 setae, dorsal seta (ds) on marginal rim, ventral seta (vs) more lateral, Subanal scale (hypoproct, hp) semicircular, unmodified, with 1+1 marginal setae.

GONAPOPHYSES. Short, triangular.

GONOPOD APERTURE. Transversely oval, more than twice as broad as long, rim simple.

GONOPODS ( Figs 5–6 , 8–9 , 11–12 ). No sternal remnant. Coxa (cx) cylindrical, short, length ≈ diameter (perhaps slightly longer in M. pallidus ), with a conical process (cxp) distally on the anterior side (absent to barely discernible in M. divisus sp. nov.); two long setae on anterior surface basal to process, a field of up to ca a dozen setae (ls) on lateral surface (except in M. louishanseni sp. nov. and perhaps M. pallidus ) and numerous setae on meso-posterior surface. Cannula (ca) stout. Prefemoral part (prf) bent at right angles relative to cx, cylindrical: length 2–2½ × diameter (maybe slightly less in M. pallidus ), numerous long setae on ventral surface. Efferent canal running straight on meso-dorsal side of prf, at level of base of parasolenomere bending laterad into solenomere; prefemoral process (prp) originating dorso-laterally from main body of prf, at least as long as solenomere and parasolenomere, basally slender, apically more or less expanded, of species-specific shape and curving over solenomere and parasolenomere; prf distally delimited by cingulum (ci), cingulum very distinct on ventral side of gonopod (except in M. kitungulu Enghoff sp. nov. where it is less distinct). Acropodite: main body strongly reduced, indiscernible, giving rise to solenomere and parasolenomere. Solenomere (slm) slightly shorter than prp (apparently same length in M. pallidus according to the original decription of that species), several times as long as broad, of species-specific shape, either regularly tapering or abruptly narrowing at ⅔ of its length. Parasolenomere (ps) originating mesal to slm, of species-specific shape, more or less shorter than slm, sometimes simple, sometimes deeply divided into two branches.

The following descriptions of individual species of Morogorius focus on species-specific characteristics. For body parts which are not mentioned, the general description of genus Morogorius applies.

Figures

Fig. 2. Chelodesmids from the Udzungwa Mts. A. Morogorius divisus Enghoff sp. nov., paratype, ♀ (NHMD 1184699). B. Morogorius louishanseni Enghoff sp. nov., paratype, ♂ (NHMD 1184563). C–D. Tanzaniella howelli Hoffman, 1977. C. Freshly preserved specimen (uncatalogued). D. Female from Mwanihana (NHMD 1184730). E. Dionaeadesmus force Enghoff gen. et sp. nov., paratype, ♀ (NHMD 1184572), rings 11–13 missing. F. Callistocilla dolorotrix Hoffman, 2005, male from Udzungwa Scarp Nature Reserve (NHMD 1184742). Scale bars: A–B, D–F = 2 mm; C not to scale. Photos: S.G. Selvantharan (A–B, D–F), A.R. Marshall (C).

Fig. 3. Morogorius divisus Enghoff sp. nov., paratype, ♂ (NHMD 1184702). A. Head, right antenna, collum and rings 2–3, oblique view.B. Clypeus and labrum. C. Head, collum and rings 2–3, dorsal view. D. Microsculpture of prozonite, ring 9. E. Ring 9, dorsal view. F. Rings 8–9, lateral view. G. Stigmata of ring 8, lateral view. H. Left paranotum and ozopore of ring 9, lateral view. Abbreviations: asp = anterior spiracle; eg = epicranial groove; lg = labrogenal offset; pe = peritreme with ozopore; pop = posterior spiracle; ts = transverse sulcus. Scale bars: A, C, E–F = 0.5 mm; B, G–H = 0.1 mm; D = 0.05 mm.

Fig. 7. Morogorius louishanseni Enghoff sp. nov., paratype, ♂ (NHMD 1184713). A. Ring 12, dorsal view. B. Rings 11–12, lateral view. Scale bars = 0.4 mm.

Fig. 10. Morogorius kitungulu Enghoff sp. nov., holotype, ♂ (NHMD 1184573). A. Rings 11–12, dorsal view. B. Ring 12, right paranotum, dorsal view. C. Ring 12, right paranotum, lateral view. D. Paranotal dorsal microsculpture. E. Tip of epiproct, with spinnerets and lateral knobs. F. Midbody leg. Scale bars: A = 1 mm; B–C = 0.2 mm; D = 0.01 mm; E = 0.1 mm; F = 0.4 mm.

Fig. 4. Morogorius divisus Enghoff sp. nov., paratype, ♂ (NHMD 1184702). A. Telson, ventral view. B. Tip of preanal process (epiproct) with spinnerets, posterior view. C–D. Right leg 10, anterior views. E. Sterna 11–12. F. Midbody dorsal limbus. Abbreviations: ds = dorsal seta on anal valve; ep = epiproct; gs = globular swelling; hp = subanal scale (hypoproct); pp = anal valve (paraproct); vs = ventral seta on anal valve. Scale bars: A, C–E = 0.5 mm; B = 0.05 mm; F = 0.02 mm.

Fig. 5. Morogorius divisus Enghoff sp. nov., paratype, ♂ (NHMD 1184699), left gonopod, A. Ventral view. B. Dorsal view. C. Lateral view with directions indicated. D. Submesal view. E. Mesal view. Abbreviations: as = anterior coxal setae; ca = cannula; ci = cingulum; cx = coxa; ls = lateral coxal setae; prf = prefemoral part; prp = prefemoral process; ps = parasolenomere; slm = solenomere. Scale bars = 0.2 mm.

Fig. 6. Morogorius divisus Enghoff sp. nov., paratype, ♂ (NHMD 1184701), right gonopod, prefemoral process cut at X. A. Meso-ventral view. B. Sub-anterior view. C. Tip of solenomere. D. Separated prefemoral process. Abbreviations: ps = parasolenomere; slm = solenomere. Scale bars. A = 0.2 mm; B, D = 0.1 mm; C = 0.01 mm.

Fig. 8. Morogorius louishanseni Enghoff sp. nov., paratype, ♂ (NHMD 1184653), left gonopod. A. Lateral view. B. Submesal view. C. Dorsal view. D. Ventral view. E. Anterior view. Abbreviations: as = anterior coxal setae; ca = cannula; ci = cingulum; cx = coxa; cxp = coxal process; mvs = mesoventral setae; prf = prefemoral part; prp = prefemoral process; ps =parasolenomere; slm = solenomere. Scale bars = 0.2 mm.

Fig. 9. Morogorius pugio Enghoff sp. nov., holotype, ♂ (NHMD 1184710), left gonopod. A. Lateral view. B. Tip of solenomere. C. Mesal view. D. Ventral view (most prefemoral setae trimmed). E. Parasolenomere, isolated. F. Anterior view. Abbreviations: as = anterior coxal seta; ca = cannula; ci = cingulum; cx = coxa; cxp = coxal process; ls = lateral coxal setae; nb = needlelike side branch; prf = prefemoral part; prp = prefemoral process; ps = parasolenomere; slm = solenomere. Scale bars: A, C–D, F = 0.2 mm; B = 0.02 mm; E = 0.1 mm.

Fig. 11. Morogorius kitungulu Enghoff sp. nov., holotype, ♂ (NHMD 1184573), left gonopod. A. Mesal view. B. (Dorso)lateral view. C. Ventrolateral view. D. Acropodite, meso-ventral view. Abbreviations: as = anterior coxal setae; ca = cannula; ci = cingulum; cx = coxa; cxp = coxal process; ls = lateral coxal setae; prf = prefemoral part; prp = prefemoral process; ps = parasolenomere; slm = solenomere; sr = serrate ridge of solenomere; sslm = solenomere s. str. Scale bars: A–B = 0.2 mm; C–D = 0.1 mm.

Fig. 12. Morogorius cochlear Enghoff sp. nov., holotype, ♂ (NHMD 1184574), left gonopod. A. Mesal view. B. Lateral view. C. Close-up of parasolenomere. D. Ventral view. E. Acropodite, mesal view. Abbreviations: as = anterior coxal setae; ca = cannula; ci = cingulum; cx = coxa; cxp = coxal process; ls = lateral coxal setae; prf = prefemoral part; prp = prefemoral process; ps = parasolenomere; psp = process of parasolenomere; slm = solenomere; sslm = solenomere s. str.; tr = triangular canopy of prefemoral process. Scale bars: A–B, D = 0.2 mm; C, E = 0.1 mm.