Otostigmus (Parotostigmus) samacus Chamberlin, 1944

Chagas-Jr, Amazonas, 2016, A systematic appraisal of the types of ten species of Otostigmus (Parotostigmus) (Scolopendromorpha, Scolopendridae, Otostigminae), Zootaxa 4147 (1), pp. 36-58 : 47-49

Otostigmus (Parotostigmus) samacus Chamberlin, 1944

( Figures 22–25 )

Otostigmus samacus Chamberlin, 1944: 175 ;

Otostigmus (Parotostigmus) samacus Bücherl, 1974: 117 .

Type material examined. Holotype FMNH-INS 0 0 0 0 0 0 8 437, Guatemala, Samac , Alta Vera Paz, Lieon Mandel Guatemala Expedition, March 27, 1934, col. By Daniel Clark, 13.vi.1934 ( Figs 22–23 ).

Redescription (male). Length: 42 mm from the anterior margin of the cephalic plate to the posterior margin of tergite 21. Antennae with 17 articles, the two basal articles and the basal part of the third article glabrous. Cephalic plate smooth, without sutures, and with very shallow depressions at posterior border (almost slightly concave). Cephalic plate slightly longer than wide.

Coxosternal tooth-plates wider than long, with 4+4 teeth and a strong seta on each plate; coxosternite with a transverse suture at the base of the tooth-plates; this suture is laterally bifurcate; a short median longitudinal suture present. Forcipular trochanteroprefemoral process larger than tooth-plates, the margin with one short denticle and pointed tip.

Tergites 4 (5)–20 with complete paramedian sutures (four to caudad); tergites 6 (7)–21 marginate (only tergite 21); tergites 1 and 2 smooth (dorsal plates smooth), tergites 3–20 with lateral rugosities; tergites 6–20 with a very shallow median longitudinal keel; tergite 21 with posterior margin slightly convex, and with a shallow rounded depression (moderately produced and widely convex at middle) ( Fig. 24 ).

Sternites without sutures; sternites 2–20 with rounded depressions (each plate typically with a short median longitudinal impression); sternites 2–11 with one rounded depression at center, sternites 12 to 20 with two small rounded depressions longitudinally at center (a short longitudinal impression is also present on each side near the middle); sternites 14–18 with a small rounded posterior depression (one on caudal border). Sternite 21 with posterior margin slightly convex (strongly narrowed caudad with caudal margin between rounded corners nearly straight); shorter than the preceding sternite; a shallow median longitudinal depression present (median longitudinal furrow across caudal border) ( Fig. 25 ).

Coxopleuron without spines. Pore-field covers almost all coxopleuron, only posterior end poreless. Posterior part of the coxopleuron with a very short rounded process (slightly and bluntly extended toward inner corner). The process is poreless ( Fig. 25 ). Left leg 1 with a tibial spur and two tarsal spurs; right leg 1 without a tibial spur, with one tarsal spur (legs 1 with two tarsal spurs). Legs 2–19 with one tarsal spur. Prefemur of first four legs short and convex distoventrally; the remaining legs also with a convex distoventrally but much less pronounced. Prefemur of ultimate legs with a digitiform appendix three-fourths the length of the prefemur (clavate process extending caudad from near base of inner side to over somewhat more than two-thirds the length of prefemur), slightly flattened dorsoventrally, clavate and with a tuft of pale yellow hairs dorsally at tip (dorsal) ( Fig. 24 );

Remarks. Chamberlin (1944) considered that O. samacus was close to O. scabricauda in the presence of the digitiform appendix in the prefemur of the ultimate legs. However, it differs from the latter by the position of the tuft of hairs on the tip of the digitiform appendix. The tuft of hairs in O. samacus is located in a dorsal position at the tip, but in O. scabricauda the tuft of hairs is located right at the tip of the appendix, in a terminal position. O. samacus is very close to O. suitius according to the type material examined in this work.

Figures

FIGURES 22 – 23. Otostigmus (P.) samacus. Holotype FMNH-INS 0 0 0 0 0 0 8 437, male. 22. Habitus, (dorsal view). 23. Habitus, (ventral view). Scale bars 5 mm.

FIGURES 24 – 25. Otostigmus (P.) samacus. Holotype FMNH-INS 0 0 0 0 0 0 8 437, male. 24. Tergite of ultimate leg-bearing segment and prefemur of ultimate legs showing the digitiform appendix. 25. Sternite and coxopleuron of ultimate leg-bearing segment, and prefemur of ultimate legs showing the digitiform appendix. DA—Digitiform appendix; TH—Tuft of hairs. Scale bars 0,5 mm.