Trichopolydesmidae from Cameroon, 1: The genus Hemisphaeroparia Schubart, 1955. With a genus-level reclassification of Afrotropical genera of the family (Diplopoda, Polydesmida)

Abstract In addition to one of the two species of Trichopolydesmidae hitherto recorded from Cameroon, Polydesmusintegratus Porat, 1894, which is revised based on type material and shown to represent the genus Hemisphaeroparia Schubart, 1955, comb. n., 12 new species from the same genus are described from that country: H.zamakoesp. n., H.bangoulapsp. n., H.spinigersp. n., H.ongotsp. n., H.digitifersp. n., H.parvasp. n., H.fuscasp. n., H.bonakandasp. n., H.bamboutossp. n., H.subfalcatasp. n., H.falcatasp. n. and H.mouankosp. n. A key to all 13 species (of Hemisphaeroparia) known to occur in Cameroon is presented, and their distributions are mapped. All ten recognizable (but excluding two dubious) Afrotropical genera or subgenera of Trichopolydesmidae are rediagnosed and reclassified, based both on their type species and a presumed scenario of gonopodal evolution. As a result, the number of accepted genera is reduced to five: Sphaeroparia Attems, 1909 (= Megaloparia Brolemann, 1920), Physetoparia Brolemann, 1920 (= Elgonicola Attems, 1939, syn. n., = Mabocus Chamberlin, 1951, syn. n., = Heterosphaeroparia Schubart, 1955, syn. n.}, Eburodesmus Schubart, 1955, Mecistoparia Brolemann, 1926 (= Dendrobrachypus Verhoeff, 1941, syn. n.), and Hemisphaeroparia.


Introduction
The millipede family Trichopolydesmidae, not long ago largely referred to as Fuhrmannodesmidae, a group that mainly included tropical taxa (e.g., Hoffman 1980, Golovatch 1994, Mauriès and Heymer 1996 as opposed to the originally Mediterranean Trichopolydesmidae, presently contains ca. 140 species from ca. 75 genera, mainly across the Northern Hemisphere, both temperate and, especially, tropical (Golovatch 2013, Golovatch andEnghoff 2015). Even after the resurrection of the small and mainly Nearctic family Macrosternodesmidae from synonymy to Trichopolydesmidae, as recently proposed by Shear and Reddell (2017), the diversity of trichopolydesmids in the restricted sense remains impressive.
Apparently because of the small to very small bodies (3-20 mm long), regional tropical faunas of Trichopolydesmidae are particularly poorly known. This fully applies to the Afrotropical realm which, based on the latest review of the mainland fauna (Mauriès and Heymer 1996) and updated here using the available information about adjacent insular faunas (Golovatch and Korsós 1992, Mauriès and Geoffroy 1999, Golovatch and Gerlach 2010, contains only two accepted genera (Bactrodesmus Cook, 1896 and Sphaeroparia Attems, 1909) and ca. 40 species. Quite a few of these species still remain obscure, e.g., Sphaeroparia? sp. from the Seychelles Korsós 1992, Golovatch andGerlach 2010) or several Mauritacantha spp. from the Reunion (= Mauritius) Island (Mauriès and Geoffroy 1999). The same also concerns Polydesmus integratus Porat, 1894 and P. parvulus Porat, 1894, both from unknown localities and both representing the only species of Trichopolydesmidae hitherto reported from Cameroon (Porat 1894).
The present paper puts on record most of a rich fresh collection of Trichopolydesmidae from Cameroon, provides the results of a revision of the sole male type of P. integratus and thus seriously updates the fauna of this family not only in the country, but in entire Africa. Unfortunately, the type series of P. parvulus, which also contained male material (Porat 1894), remains unavailable for restudy, apparently being misplaced in the Stockholm Museum. A new generic classification of the Afrotropical trichopolydesmids is also proposed, a key to and a map of all trichopolydesmids currently known to occur in Cameroon are also given.

Material and methods
Most of the material treated here derives from the collection of the Musée Royal de l'Afrique Centrale (MRAC), Tervuren, Belgium, with only a few duplicates retained for the collections of the University of Yaounde 1 (UY1) and the second author (ARNF), Cameroon or donated to the Zoological Museum, State University of Moscow (ZMUM), Russia, as indicated below. The samples are stored in 70% ethanol. Specimens for scanning electron microscopy (SEM) were air-dried, mounted on aluminium stubs, coated with gold and studied using a JEOL JSM-6480LV scanning electron microscope. The colour pictures were taken using the focus stacking set up described by Brecko et al. (2014). Canon EOS Utility software was used to control the camera. Zerene Stacker was applied for stacking the individual pictures into one 'stacked image'.
The abbreviations used to denote gonopodal structures are explained directly in the text and figure captions.

A generic reclassification of Afrotropical Trichopolydesmidae
The high number of generic categories (12 genera or subgenera, see below) to adopt some 35 species recorded throughout continental tropical Africa (Mauriès and Heymer 1996) is likely evidence of the poor state of the art. One more genus, Mauritacantha Verhoeff, 1939, from Mauritius, remains invalid as no proper typification has ever been done (Verhoeff 1939). The suggestion by Mauriès and Geoffroy (1999) of Mauritacantha lawrencei Verhoeff, 1939 as a potential type species of this genus is not a valid act of typification and is thus to be ignored.
The following nomenclaturally available generic or subgeneric names have been suggested to accommodate the Afrotropical Trichopolydesmidae, arranged below in alphabetic order and followed by their brief descriptions and gonopodal characters (Figs 1, 2), as well as provenance, all this derived from the original descriptions of their type species alone.
The genus was first proposed as a nomen nudum (Cook 1896a), but then properly typified (Cook 1896b). The sole useful information contained in the original description of B. claviger concerns its small size (7 mm long, 1 mm wide), typically micropolydesmid facies (small paraterga, large and clubbed tergal setae arranged in three transverse rows etc.), strongly enlarged gonocoxae that fully conceal the telopodites and, above all, male legs 2, especially their tibiae, greatly enlarged compared to others (Cook 1896b). No number of body segments has been given.
Gonopodal coxa very large, concealing most of telopodite; the latter's apical part with only one branch (ab); seminal groove simple and rather long, ending subapically on a long solenomere (sl) ( Figure 2D).
Twenty segments (male, female); body length 6.5 mm. Male head without epicranial modifications. Paraterga moderate, tergal setae very short. Gonopodal coxae unusually small, leaving telopodite mostly exposed and suberect; telopodite bipartite, seminal groove short and simple, ending on a short solenomere (sl) with a hairy pulvillus squeezed between both branches ab and bb ( Figure 1B).
The above brief accounts are given to reiterate the foundations of the previous classification and to offer a new one below. The classification developed by Mauriès and Heymer (1996) in their review of the African Trichopolydesmidae (= Fuhrmannodesmidae) cannot be accepted because it totally lacks any evolutionary perspective. These authors themselves admit their approach as being "bastard" and overly lumping, as they placed all species but one (Bactrodesmus, dubious) in the single genus Sphaeroparia, within which they accepted six subgenera and suggested several synonymies. Golovatch (1992Golovatch ( , 1994 provided an evolutionary scenario for the genera of Trichopolydesmidae (= Fuhrmannodesmidae) known from South America, accepting as the basalmost those genera showing rather small, narrowly fused 1 , subglobose gonopodal coxae that form no significant gonocoel in which to hinge the largely exposed, usually rather complex and elongate telopodites. Amongst the Afrotropical trichopolydesmids such are the genera Elgonicola, Heterosphaeroparia,Megaloparia,and Sphaeroparia (Figs 1D,2A,1B,and 1A,respectively). At the opposite end which obviously represents the evolutionary summit are such genera as Dendrobrachypus, Eburodesmus, and Mecistoparia (Figs 2D, E and 2B-C, respectively). Their gonopodal coxae are especially voluminous and inflated laterad; the particularly deep gonocoel is capable of concealing entire or nearly entire telopodites. Sometimes the coxa shows a rather conspicuous apicolateral process or lobe, this being suberect (Heterosphaeroparia, Figure 2A, cp) or directed more or less mesally (Eburodesmus, Figure 2E, cp). Schubart (1955) created his Eburodesmus, based on such evident and more or less mesally directed coxal processes ( Figure 2E, cp), but we think this may be only a species-level character occasionally present also in distinctly more basal taxa, e.g., Heterosphaeroparia (Figure 2A, cp). A series 1 Shear and Reddell (2017) have recently suggested to consider the polydesmidan gonopodal coxae fused only when the medial fusion is as strong as that observed in the Dalodesmidea. However, the gonocoxae in the Polydesmidea are also fused not only basally to their sternum, but also medially through two small chitinous flaps, each typically supporting two strong setae. However slight, this is also fusion, a condition which may be termed "narrowly fused". of transitions can be seen between the two extremes, e.g., in Heterosphaeroparia, Elgonicola or Hemisphaeroparia, when 1-3 prominent branches project well beyond the coxal margin, while the telopodite is mainly deeply sunken inside the coxa. Typically there are 2+2 particularly strong setae near the place of central fusion of both coxae, while their lateral surfaces are normally more or less clearly granulate/alveolate and setose.
The cannula in Afrotropical Trichopolydesmidae is invariably medium-sized, tubeshaped, strongly curved, long, and slender, its tip entering the densely setose, funnelshaped, "prefemoral" part of the telopodite which extends from base to apex. The seminal groove is mostly rather short and straight, usually running on the mesal side to end on a simple, more or less finger-or spine-shaped, sometimes retrorse solenomere (sl). In a few cases, the solenomere ends near a kind of hairy pulvillus or shows a tooth at its base. However, there is a remarkable exception, when the seminal groove makes a distinct loop before proceeding onto a prominent solenomere (e.g., Eburodesmus, Figure 2E). Such situations seem to imply telopodite torsion. The length of a solenomere is usually barely more than species-specific, but the course of the seminal groove is definitely a genericlevel character, as can be seen in Neotropical or Southeast Asian Trichopolydesmidae (Golovatch 1992, 1994, Golovatch et al. 2014, Golovatch and VandenSpiegel 2016. The gonopodal telopodite is typically helmet-or boat-shaped. At the apicolateral end which is opposite to the "prefemoral" funnel there is a group of partly especially stiff setae usually extending basad across or over most of the funnel. Variations in the shape of the remaining parts of the telopodite are especially prominent. Among the most common outgrowths or processes of the telopodite we choose to denominate the following. A unipartite telopodite which shows only a single prominent branch, apical in position (ab), is observed in Dendrobrachypus, Mabocus, Mecistoparia and Physetoparia (Figs 2D, 1E-F, 2B-C and 1C, respectively). Bi-or tripartite telopodites are more usual, sometimes also supplied with evident central lobes (lo). The branch which is the closest to the apex is denominated an apical branch (ab), while that lying the closest to the basal part is termed a basal branch (bb). If there is another branch located between ab and bb, this is a medial branch (mb). Two of or all three branches are often strongly adjacent to each other. A few species groups may be provisionally outlined based on the general conformation of the gonopodal telopodites.
Two different general trends can be observed in the evolution of the gonopods in Afrotropical Trichopolydesmidae. While the coxa tends to grow and develops an increasingly prominent gonocoel, the originally relatively complex and largely exposed telopodite, at least in some cases, seems to shrink gradually and often becomes simplified. Indeed, the presumably basal taxa with particularly small gonocoxae (e.g., Sphaeroparia, Elgonicola or Megaloparia, Figs 1A, 1D and 1B, respectively) show complex apical structures on telopodites. In cases like Eburodesmus ( Figure 2E) and Heterosphaeroparia (Figure 2), it is the coxal apicolateral process (cp) that takes the protective function to secure the still complex and exposed parts of the telopodite. Usually, when the outgrowths are mostly concealed and little exposed beyond the coxa, they are particularly few and sometimes reduced just to one branch (e.g., Dendrobrachypus, Figure  2D or Mecistoparia, Figure 2B, C). Interestingly, the single species of Sphaeroparia, S. simplex Golovatch, 2013, described from the Balkans and several Greek islands (Golovatch 2013), i.e., well beyond the Afrotropical realm, shows voluminous gonopodal coxae and especially simple and small telopodites, these latter being mostly concealed inside the gonocoel. Now that Sphaeroparia receives a clear definition (see below) and joins the basal group of genera with still small gonocoxae and complex and well-exposed telopodites, the identity and generic allocation of S. simplex must be revised (Vagalinski et al., in preparation).
When a delicate solenomere is left well-exposed (Figs 1C, 2D, F-G), it appears to always be protected by adjacent stronger structures serving as a solenophore. The number and shapes of such accessory outgrowths (processes and lobes) varies between species, but they are always few (1-3) and tend to be little exposed to fully concealed or even absent in more advanced genera.
Such are the main guidelines, all based solely on gonopodal anatomy, to follow in order to obtain new generic delimitations arranged according to an increasing complexity of the coxae, combined with a decreasing complexity of the telopodites. Somatic characters such as the number of body segments (19 in the male or in both sexes, or 20 in both sexes), the pore formula (always normal, but can be a little abbreviated on the last 1-2 segments before the telson: 5, 7, 9, 10, 12, 13, 15-17(18,19)), the degree of development of paraterga (usually moderate, often small, but never really well-developed and strongly flattened dorsally), the position of the ozopores (usually open flush dorsally near the caudal corner of pore-bearing paraterga), the shape of tergal setae (short and clavate to very long and bacilliform), the presence of modifications on male legs 2 (enlarged in Bactrodesmus) and on the male head (ranging sporadically from nothing to a strong, central bulge or a mushroom-like or bulbous tubercle), they all are considered here as species-specific. This situation agrees with general wisdom derived from other tropical faunas (Golovatch 1994, Golovatch et al. 2014. A somatic character that deserves special mention is the unusually strongly developed peri-spiracular structure on segment 2. In all new species described below, the spiracle is located on a high finger with a complex tip placed next to coxa 2 (Figs 11K, 21J-L). Is this a generic feature that characterizes Hemisphaeroparia? Could Cook (1896b) have mistaken the spiracle for leg 2 in his Bactrodesmus?
The generic reclassification presented below considers only the type species, leaving aside the other component species and their allocations to our next paper on Afrotropical Trichopolydesmidae (Golovatch et al., in preparation). Two nominal genera, Bactrodesmus and Trichozonus, are dubious and are for the time being to be discarded from further consideration, because their gonopodal characters remain unknown. Whereas B. claviger is generally possible to revise or recognize based either on type or topotypic material from Liberia, since male legs 2 of this species are said to be conspicuously enlarged (Cook 1896b), the identity of T. escalerae is bound to remain obscure (Carl 1905) until a male topotypic sample from Fernando Po becomes available for study.
Remark. This genus is presumably among the basalmost representatives of Afrotropical Trichopolydesmidae.

Type-species. Sphaeroparia imbecilla
Remarks. This genus is among the more advanced representatives of Afrotropical Trichopolydesmidae. Mauriès and Heymer (1996: 168) regarded it as a subgenus of Sphaeroparia, with Hemisphaeroparia and possibly also Dendrobrachypus and Trichozonus as synonyms of Physetoparia.
Remarks. This genus is among the more advanced representatives of Afrotropical Trichopolydesmidae. Mauriès and Heymer (1996: 168) regarded it as a subgenus of Sphaeroparia.
Genus Eburodesmus Schubart, 1955, stat. revalid. Schubart, 1955 Diagnosis. Both gonopodal coxae and gonocoel very large; telopodite only barely exposed, but complex (this possibly being in correlation that each coxa has a protective apicolateral process), with two strong branches (ab and bb); seminal groove long and forming a conspicuous loop before moving onto a caudally located solenomere ( Figure 2E).

Type-species. Eburodesmus erectus
Remarks. This genus is among the most advanced representatives of Afrotropical Trichopolydesmidae. Mauriès and Heymer (1996: 168) regarded it as a subgenus of Sphaeroparia.
Genus Hemisphaeroparia Schubart, 1955, stat. revalid. Schubart, 1955 Diagnosis. Both gonopodal coxae and gonocoel large to very large; telopodite usually moderately to barely exposed, but complex, with 1-3 strong branches (ab and/ or bb, or ab, mb and bb, occasionally also with a lobe more basally), only sometimes with a single particularly strongly exposed branch (ab); seminal groove mostly short, solenomere only sometimes absent, but usually finger-shaped and located caudomesally ( Figure 2F, G).

Type-species. Hemisphaeroparia cumbula
Remarks. This genus is among the most advanced representatives of Afrotropical Trichopolydesmidae. Mauriès and Heymer (1996: 168) regarded it as a synonym of Physetoparia. All trichopolydesmid species treated below from Cameroon appear to belong to this genus, albeit forming a few species groups.
Based on the numerous new and one old species from Cameroon treated below, the diagnosis of Hemisphaeroparia can be updated as follows.
Updated diagnosis. Body with 19 or 20 segments. Male epicranial modifications present or absent. Spiracle next to coxa 2 conspicuously enlarged, finger-or mushroom-shaped and with a complex tip. Both gonopodal coxae and gonocoel large to very large; telopodite usually moderately to barely exposed, but complex, with 1-3 strong branches (ab and/or bb, or ab, mb and bb, occasionally also with a lobe more basally), only sometimes with a single particularly strongly (ab) or considerably (bb) exposed branch; seminal groove mostly short, solenomere only sometimes absent, but usually transverse (= directed anteriorly), finger-shaped or spiniform, and located caudomesally. Diagnosis. Differs from all other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with unusually densely setose gonopodal telopodites which are deeply sunken inside a large gonocoel and show only two, slender, contiguous, little-exposed branches (ab, bb), both followed by a small, round, fully concealed lobe (lo) more basally (Figure 4).

Hemisphaeroparia bangoulap
Diagnosis. Differs from other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with well-exposed gonopodal telopodites that show not only slender branches ab and bb, but each also a well-expressed lobe (lo) with an unusually deep transverse gutter (g) with very strongly thickened walls at the base, as well as a vestigial solenomere (sl) with a remarkable process (t) near its base ( Figure 6).
All other characters as in H. zamakoe sp. n., except as follows.
Gonopodal telopodites more strongly exposed, less strongly setose, both main branches (ab, bb) longer, lobe (lo) also exposed, at base on lateral face with a prominent transverse gutter (g) with unusually strongly chitinized walls; branch bb sometimes subdivided into two flagelliform branchlets ( Figure 6F, G). Seminal groove short, solenomere (sl) rudimentary, near its base with a conspicuous process (t).  Diagnosis. Differs from other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with unusually densely setose gonopodal telopodites which are deeply sunken inside a large gonocoel and show not only two slender, little- Figure 6. Hemisphaeroparia bangoulap sp. n., ♂ paratypes A-C SEM micrographs of right gonopod, mesal, ventromesal, subventromesal views, respectively D-G right (D, E) and left (F, G) gonopods, mesal, lateral, mesal and lateral views, respectively. Scale bars: 0.05 (A-C), 0.2 mm (D-G). Abbreviations: ab apical branch of telopodite, bb basal branch of telopodite, g gutter, lo lobe, sl solenomere, t process. exposed branches (ab, bb), followed by a small, round, fully concealed lobe (lo) more basally, but also a conspicuous transverse spine arising on the lateral side near the base of ab and bb (Figure 8).
Name. To emphasize the long, transverse spine on the gonopodal telopodite; noun in apposition.
Gonopods (Figure 8) forming a deep gonocoel, telopodites only slightly exposed through distal halves of their two main branches (ab, bb), both contiguous over most of their length and both subequal in shape and length, followed by a low rounded lobe (lo). Basal part of telopodite densely setose throughout; distobasal part with a conspicuous transverse spine (sp) arising near base of ab and bb on lateral side, but hidden on both sides. Seminal groove short, moving onto a longer or shorter solenomere (sl) on mesal side. Diagnosis. Differs from all other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with the caudal corner of paraterga becoming increasingly strongly drawn behind the rear tergal margin starting with segment 13 and the gonopodal telopodites that are deeply sunken inside a large gonocoel and show three main branches (ab, mb, bb), all well-exposed and followed  by no lobe, as well as a short solenomere with a tooth (t) at base of both sl and ab ( Figure 10).
All other characters as in H. zamakoe sp. n., except as follows. Caudal corner of paraterga always rounded, drawn increasingly back, but reaching beyond rear tergal margin on segments 13-18 ( Figure 9A-C).
Gonopodal telopodite (Figure 10) deeply sunken inside a deep gonocoel, densely setose at base with three main branches (ab, mb, bb) mostly exposed: bb the shortest and rounded on top, mb slightly curved and subtruncate, and ab the longest and also slightly curved. Seminal groove relatively long, ending on a short solenomere (sl) supplied with an evident tooth (t) at base of sl and ab.  Diagnosis. Differs from all other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with the gonopodal telopodites that are deeply sunken inside a large gonocoel and show three main branches (ab, mb, bb), all exposed in their distal parts and followed by no lobe, but instead with a conspicuous, setose, fully concealed finger (d) basally in apical part; seminal groove relatively long and straight, ending subapically on ab without any trace of a solenomere ( Figure 12).
All other characters as in H. zamakoe sp. n., except as follows. Body with 20 segments. Antennae long and strongly clavate, reaching back to segment 3 when stretched dorsally (♂). Tergal setae mainly short, each often ca. 1/6-1/7 as long as metatergum, bacilliform, or subclavate ( Figure 11A-F, L). A faint transverse sulcus often traceable between rows 1 and 2 of setae on some metaterga. Segment 2 with a prominent and apically complex spiracle on each side ( Figure 11K).
Legs rather long and slender, ca. 1.2-1.3 times as long as midbody height (♂). Gonopods ( Figure 12) with a deep gonocoel and complex, only little-exposed telopodites, the latter complex, showing subequally high ab and mb branches, the longest and most curved branch being bb. Apical part of telopodite with a conspicuous, long, and abundantly setose finger (d). Seminal groove long and straight, ending subapically on ab without any trace of a solenomere. Diagnosis. Differs from other species of the genus by having 19 body segments and by the absence of epicranial modifications in the ♂, coupled with the presence of only a single prominent branch (ab) which is exposed beyond the gonopodal coxa only distally; ab at the base with a large, lateral, finger-shaped process (lp); the seminal groove is rather long and moves onto a very short and retrose solenomere (sl) apically ( Figure 14).
Gonopodal telopodite (Figure 14) almost fully concealed inside a deep gonocoel, with only a single prominent branch (ab), this being exposed beyond coxa only distally; ab at base with a large lateral process (lp). Seminal groove rather long, moving onto a very short and retrose solenomere (sl) apically.  Diagnosis. Differs from all species of the genus by the absence of epicranial modifications (♂), coupled with the clearly more strongly developed and caudally acute paraterga compared to H. zamakoe sp. n. and most other congeners, as well as the presence of three prominent branches (ab, mb and bb) and a low lobe (lo) on the gonopodal telopodite and of a conspicuous foramen (fo) in the lateral wall to accommodate the end of the solenomere (sl) in a kind of pulvillus ( Figure 16).
Gonopodal telopodites (Figure 16) almost fully concealed inside a large gonocoel, with three branches (ab, mb, bb), all contiguous and moderately only exposed beyond coxa, followed by a small round lateral lobe (lo) more basally. Seminal groove short, moving onto a short subspiniform solenomere (sl), the latter subtransverse and directed laterad, and perforating the lateral wall to form a conspicuous foramen (fo) resembling a pulvillus because of numerous microscopic transparent filaments around. 1 ♂ (lost), same locality, together with holotype. Diagnosis. Differs from other species of the genus by the presence of a boletiform epicranial tubercle (♂), coupled with relatively long tergal setae, line-shaped and microgranulate pleurosternal carinae, as well as deeply sunken gonopodal telopodites, each of which shows a single, moderately exposed, main branch (ab) and a rather short, subtransverse, laterally directed solenomere (sl), with a sharp tooth at its base ( Figure  18).
Gonopodal telopodites (Figure 18) almost fully concealed inside a large gonocoel, with only one unequally bifid branch (ab) moderately strongly exposed beyond coxa. Seminal groove short, moving onto a short, subspiniform solenomere (sl), the latter subtransverse and directed laterally, with a short tooth (t) at base.   C, E, F, H), 0.05 mm (J, L), 0.01 mm (K). erately exposed above a deep gonocoel, each telopodite with only two branches (ab, bb), contiguous and followed by a small rounded lobe (lo) more basally. Branch bb shorter, with a conspicuous distomesal tooth (t). Seminal groove short, ending on a short retrorse solenomere (sl) nearly level with bb tip.
Gonopodal telopodites (Figure 20) only moderately exposed above a deep gonocoel, each with only two branches (ab, bb), both being contiguous and followed by a small rounded lobe (lo) more basally. Branch bb shorter, with a conspicuous distomesal tooth (t). Seminal groove short, ending on a short retrorse solenomere (sl) nearly level with bb tip. Diagnosis. Differs from other species of the genus by the presence of a boletiform epicranial tubercle (♂) and 19 segments in both sexes, coupled with the gonopodal telopodites ( Figure 22) showing only one, but especially prominent and subfalcate main branch (ab), this being very strongly exposed beyond coxa; a long spiniform solenomere (sl) is subtransverse, directed forward and shows a short truncated tooth (t) at its base.

Hemisphaeroparia subfalcata
Name. To emphasize the subfalcate gonopodal branch ab; adjective in feminine gender.
Gonopodal telopodites (Figure 22) almost fully concealed inside a large gonocoel, each with only one main branch (ab), this being long, subfalcate, and very strongly exposed beyond coxa. Seminal groove short, at around midlength moving onto a long, spiniform solenomere (sl), the latter subtransverse, directed forward and showing a short truncated tooth (t) at base.  Diagnosis. Differs from other species of the genus by the presence of a particular epicranial tubercle with fine filaments on top (♂), of 19 body segments (♂), coupled with only one main branch (ab) on the gonopodal telopodite, this branch being very strongly exposed, very long, falcate and directed laterally, followed by a very small lobe (lo) more basally (Figs 23M,24). No solenomere.
Name. To emphasize the strongly falcate gonopodal branch ap; adjective in feminine gender.
Gonopodal telopodites (Figs 23M, 24) almost fully concealed inside a very large gonocoel, each with only one main branch (ab) very strongly exposed beyond coxa, being also unusually long, falcate and directed laterally, followed by a very small round lobe (lo) more basally. Seminal groove short, ending on a small squarish lobe without a solenomere. Diagnosis. Differs from other species of the genus by 19 body segments (♂), the presence of a boletiform epicranial tubercle inside a depression (♂), coupled with each gonopodal coxa supplied with two unusually strong basal setae and the telopodites which are deeply sunken inside a large gonocoel and show only two, contiguous, littleexposed branches (ab, bb). The solenomere (sl) is long and finger-shaped ( Figure 26).
Name. To emphasize the type locality; noun in apposition. Description. Length of holotype and paratype ca. 3.5 mm (♂), width of midbody pro-and metazonae 0.2 and 0.35 mm (♂), respectively. Colouration in alcohol almost uniformly very light yellow brownish ( Figure 29F).
Legs rather long and slender, ca. 1.3-1.4 times as long as midbody height (♂); tarsi in anterior body half with ventral brushes ( Figure 25K).
Gonopodal coxa with two unusually strong setae at base, at fusion site of both coxae (Figs 26C, D). Telopodite (Figure 26) almost fully concealed inside a very large gonocoel, each with only two branches (ab, bb), both contiguous and only slightly exposed beyond coxa, followed by no lobe more basally. Branch ab a little longer and faintly subdivided into two, branch bb shorter and slightly curved at tip. Seminal groove short, moving onto a long finger-shaped solenomere (sl). (Porat, 1894), comb. n. Figure 27 Polydesmus integratus Porat, 1894: 30 (original description).
One of us (JPM) revised the types and made the present lectotype designation, the latter to ensure that the species is based on male material.
Diagnosis. Differs from other species of the genus by 20 body segments, the presence of a boletiform epicranial tubercle (♂), coupled with the gonopodal telopodites which are deeply sunken inside a large gonocoel and show only one, flagelliform, basal, main branch (bb) exposed beyond the coxa. The solenomere (sl) is short and finger-shaped (Figs 27F, G).

Key to Trichopolydesmidae from Cameroon
The following key is proposed to separate all 13 adequately known species of the family Trichopolydesmidae recorded from Cameroon (based on male characters):

Conclusions
The distribution of the genus Hemisphaeroparia, hitherto known to comprise a single, and type, species from Mt Nimba (Côte d'Ivoire and Guinea) (Schubart 1955), appears to presently cover much of western Africa. Furthermore, the whole of Cameroon, at least its better-studied southern half, supports species of this genus alone ( Figure  30). Our contribution has enriched the entire fauna of African Trichopolydesmidae by one-third, while the fauna of Cameroon becomes the best studied across the whole continent. There is little doubt that this family is taxonomically one of the most diverse throughout Africa, with numerous further species still awaiting discovery even in Cameroon. We may say that we have just touched the tip of the iceberg. Sympatry or even syntopy is not too rare among Afrotropical Trichopolydesmidae. Thus, Schubart (1955) described three different species (and genera) from Mt Nimba. Mauriès and Heimer (1996) not only published several species occurring sympatrically from eastern Africa, but they also provided a general map showing the distribution of the family and all of its genera and species then known on the continent. Our material likewise demonstrates a few cases of sympatry or strict syntopy in Cameroon, up to three species per locality (Figure 30).
With a list of already 14 species in Hemisphaeroparia alone, some of them may be grouped in a few species groups. Thus, because H. subfalcata sp. n. and H. falcata sp. n. share not only the very small body with 19 segments and certain epicranial modifications (♂), but also the particularly long branches ab of the gonopods (Figs 22, 24), they seem to belong to the same species group. Perhaps at least some of the species that show only two or all three main branches of the gonopodal telopodite form further 2-3 species groups, but we shall refrain from further outlining and naming them now pending more material becomes described. Some is already available, but remains entirely unstudied yet; further samples may be expected to come in the near future, and all this, as well as a complete species-level reclassification of African Trichopolydesmidae will be treated in the next part of our paper.