Haplogonopus Verhoeff 1941

Hoffman, Richard L., 2011, A review of the milliped genus Haplogonopus with commentary on the so-called “ Charactopygus-Bildung ” modification of spirostreptid paraprocts (Diplopoda: Spirostreptidae), Zootaxa 2734, pp. 53-62 : 54

Haplogonopus Verhoeff 1941 .

Haplogonopus Verhoeff, 1941 , Jenaische Zeitschr. Naturw., 73: 265. Proposed for a new species. Type species: H. inflatannulus Verhoeff , by monotypy.

Haplogonopus: Hoffman, 1980 , Classification of the Diplopoda, p. 93.

Definition. Moderate-sized spirostreptids, length 50–120 mm. Gonopod structure generalized; a median sternal sclerite present in various forms but basically small and transverse; coxal folds of simple form, not closely applied resulting in an open gonoschisma with telopodite partly visible in anterior aspect, metaplica produced laterad as an acuminate projection, proplica slightly broadened distally, produced distomesad, the mesal edge bearing a slender aciculate apical process ( Figs.6–8 , a). Telopodite long and slender, carried on the anterior side of coxal folds, torsal region distinctly distad of arculus, elongated and gradual, an antetorsal process present in one species, posttorsal telopodite attenuated, without marginal processes, cingulate in one species, a minute apical lobe present.

Remarks. Spirostreptids are generally so conservative in terms of peripheral characters that almost any modification is conspicuous and invites utilization in the definition of new taxa. One of the features thus noted by Verhoeff and memorialized in the species name inflatannulus is the greater diameter of the metazona and their ornamentation with elongate shallow depressions (cf. Fig. 5 ). When taken in combination with the gonopod structure, such modification rather justifies Verhoeff’s decision to propose a new genus and subfamily for this one taxon..

However, a definition of the genus on the basis of gonopod structure only, as here proposed, results in the inclusion of two additional species with isoplanar metaterga and modified paraprocts, implying that the “ inflatannulus ” condition reflects differentiation at the species level only. Comparison of the drawings here provided leaves no doubt that the gonopods of these three forms are very similar, implying a close degree of relationship. The form and location of proplical process a is a convincing shared apomorphy. Perhaps some unusual environmental condition in the Uluguru Mountains evoked disjunct peripheral modifications in one of the three species.

If the peripheral features of H. inflatannulus are considered to be of specific importance only, a search for possible related taxa may be directed towards other regional genera having similar genitalic structure. Some reasonable candidates would include the nominal genera Macrolenostreptus and Elkestreptus , both with species in eastern Tanzania. Attention is also directed to the similarity of gonopod structure between H. cingulatus and the Madagascar species “ Spirostreptus ” micromelas Saussure & Zehntner, 1897, in particular the subspecies croceipes Brolemann 1923. If this similarity is not merely a case of random homoplasy in a number of traits, a case might be made for inclusion of micromelas in Haplogonopus .

Comparison of specimens should, of course, precede any formalized generic placement.

Range. Higher elevations in central Kenya and southeastern Tanzania ( Fig. 12 ).

Species. Three.

Figures

FIGURE 12. Tanzania and adjacent countries, showing known localities of the three species of Haplogonopus. Star, H. jeanneli; square, H. inflatannulus; triangle, H. cingulatus.

FIGURES 6 – 9. Haplogonopus, gonopod structure of three species. 6. H. inflatannulus, right gonopod, anterior aspect. 7. H. jeanneli, left gonopod, anterior aspect (adapted from Brolemann, 1920). 8. H. cingulatus, right gonopod, anterior aspect. 9. Midlength section of posttorsal telopodite, enlarged, to show form of cingulum. Abbreviations: a, apicomedial process of proplica; atp, antetorsal process of telopodite, mp, distal end of metaplica.

FIGURES 1 – 5. Haplogonopus inflatannulus Verhoeff., structural features. 1. Gnathochilarium and adjacent parts of mandibles and collum. 2. Right mandible, posterior aspect, with distal lobe of basomere indicated by the ↔. 3. First pair of legs of male, syncoxa, sternum, and basal podomeres, anterior aspect. 4. The same, posterior aspect, sclerite of uncertain identity indicated by the? 5. Dorsal half of three midbody segments, lateral aspect, showing convex metazona with ovoid depressions.