A mountain of millipedes VI. New records, new species, a new genus and a general discussion of Odontopygidae from the Udzungwa Mts, Tanzania (Diplopoda, Spirostreptida, Odontopygidae) Author Enghoff, Henrik text European Journal of Taxonomy 2018 2018-01-11 394 1 29 journal article 31016 10.5852/ejt.2018.394 54a11801-d3d3-4b76-9f6c-7a9c27677825 1146158 94028C61-FAC5-4A21-BF2D-A75BBF3CCC4D Genus Helicochetus Attems, 1909 Helicochetus Attems, 1909a: 158 . Type species Spirostreptus dimidiatus Peters, 1855 , by original designation. See further below. Other included species Helicochetus aberrans Kraus, 1966 ( Zambia ) , H. digititarsus Kraus, 1957 ( Democratic Republic of the Congo , Tanzania ), H. electricus Kraus, 1958 ( Democratic Republic of the Congo ), H. gregorii ( Pocock, 1896 ) ( Kenya ) , H. inversus Kraus, 1958 ( Democratic Republic of the Congo ), H. involutus Attems, 1935 ( Democratic Republic of the Congo ), H. laciniatus Attems, 1935 ( Democratic Republic of the Congo ), H. levifolius Attems, 1914 (”Sambesi”, Mozambique ), H. monodon Kraus, 1960 ( Zambia ) , H. mutaba Kraus, 1960 ( Democratic Republic of the Congo ), H. pococki (Carl, 1909) ( Tanzania ) , H. rarus Kraus, 1958 ( Democratic Republic of the Congo ). Kraus (1960) provided an identification key to the species, except H. aberrans . Remarks The material from the Udzungwa Mts includes specimens of two species of Helichochetus . Separate descriptive notes are given for each species, but two characters shared by both species may prove to be genus-characteristic and are therefore commented on here. LIMBUS ( Fig. 4A, C, E ). Kraus (1960) characterized the limbus of Helichochetus (translated from German): “Limbus divided by rounded indentations into processes which each carry three to six nail-like points. Limbus very broad, ca. 10 × as broad as the processes, with a silky sheen due to the characteristic surface sculpture (exception H. laciniatus )”. The limbus of the two studied species, especially H. mutaba , is indeed very broad ( Fig. 4A, C ), and the processes and nail-like points agree fully with Kraus’ description. It is not clear from his publications ( Kraus 1960 , 1966 ) what he meant by the “characteristic surface structure”. The SEM images ( Fig. 4A, C, E ) provide no clue. There is, however, another remarkable detail, visible in Fig. 4E : under the limbus proper, there is a “sub-limbus” consisting of rounded, almost semicircular lobes. CYTOSCUTE DENTICLES ( Fig. 4B, D, F ). The “cytoscutes”, i.e., cuticular “cells” each corresponding to a hypodermis cell ( Fusco et al. 2000 ) very often carry a row of tiny denticles along one edge. In both studied species of Helicochetus , these denticles are much larger than normal and point away from the cuticular surface rather than lying parallel to it.