Geophilus impressus, C. L. Koch, 1847, C. L. Koch, 1847

Popovici, George, 2022, Pushing the Limits: New Data on the Morphology of Geophilus impressus C. L. Koch, 1847 (Geophilomorpha: Geophilidae), Ecologica Montenegrina 53, pp. 38-44 : 39

Summary description of examined specimens

Head and antennae ( Fig. 1 A ). Cephalic plate without frontal sulcus, subquadrate, 1.15–1.17 times wider than long. Basal plate absent. Posterior margin straight, overlapping forcipular tergite. Antennae 3.6–4 times longer than cephalic plate. Articles III-XIII with single or paired sensilla brachyconica dorso-basally; sensilla trichoidea abundant, evidently longer on the dorsal side of each antennal article. Terminal article 1.76 times longer than wide; two medial fields of sensilla basiconica distributed in two grooves dorsolaterally, extending for 20% of its total length.

Labrum and clypeus ( Fig. 1 D ). Clypeus uniformly reticulate, with three pairs of postantennal setae in regular arrangement. Labrum clearly divided into three pieces; with three denticles on its medial piece and 5+5 hyaline filaments on the lateral pieces.

First maxillae ( Fig. 1 B ). Telopodites incompletely divided into two articles; with indistinct lappets; with distinct reticulation forming large cells. Second article with 1+1 large setae ventrally. Coxosternum without lappets and with incomplete medial division; uniform reticulation in the form of of large cells; 2+0 small setae ventrally. Coxosternal projections well-developed, shorter than the telopodites, with 3+3 small setae apically and 2+1 small setae basally.

Second maxillae ( Fig. 1 B ). Coxosternum undivided, with 3+3 setae apically and 2+1 setae basally; uniform reticulation in the form of large cells. Telopodites divided into three clearly separated articles. First article with 1+1 small setae laterally, second article with 1+1 small setae laterally, and third article with 3+4 large setae apically, ending in a distinct tubercle.

Forcipular segment ( Figs. 1 C , 2 A ). Forcipular tergite reduced. Forcipular coxosternite uniformly reticulated, with 45 setae and a straight, medially notched, anterior margin. 2+2 regularly spaced setae on anterior margin. Coxopleural sutures ending just before reaching the anterior margin. Chitin lines incomplete, vanishing before reaching the condyles. Tarsungulum with smooth, gently curved, internal margin and pronounced basal denticle; with 4+4 large setae basally. Calyx of venom gland short, approximately hemispheric in shape. Venom gland indistinct, located predominantly in the trochantheroprefemur.

Trunk ( Fig. 2 B ). Male with 41 and both females with 43 leg-bearing segments. Carpophagus structures distinct, well-sclerotized, consolidated, present from sternite 2-4 to sternite 17, most developed on sternites 9–11. Anterior pore fields elliptical, spindle shaped, restricted to posterior half of metasternites 2– 17. Area of pore fields separated from metatergite by indistinct anterior transverse sulcus and posterior reticulation.

Last leg-bearing segment ( Fig. 2 C ). Ultimate pleuropretergite complete. Metasternite trapezoidal, partly covering coxal organs. Each coxopleuron with 3+3 to 4+4 evident coxal organs opening ventrally and one separate, smaller, ventro-laterally positioned (inconspicuous in male specimen). Ultimate legs densely setose ventrally in both males and females, more swollen in males. Pretarsus simple, unguiform. Male gonopods biarticulate. Female gonopodal lamina indistinctly bilobed, devoid of setae. 1+1 anal organs.

Figures

Figure 1. A – Cephalic capsule and antennae, dorsal view, B – Maxillae I and II, ventral view, C – Forcipular segment, ventral view, D – Clypeus and labrum, ventral view.

Figure 2. A – Apex of right forcipule, ventral view, B – Leg-bearing segment 9, ventral view, C – Last leg-bearing and postpedal segments of female, ventral view.