Visma advenum, Smith & Mitchell & Molero-Baltanás, 2021

Smith, Graeme B., Mitchell, Andrew & Molero-Baltanás, Rafael, 2021, Molecular and morphological studies identify a new genus within the Heterolepismatinae (Zygentoma: Lepismatidae), Zootaxa 5030 (1), pp. 1-118 : 66-72

Visma advenum new species

Table 7; Figs. 5 , 210–242

Type material. Holotype, NSW: Glen Davis, Coorongooba campground 33.12458S 150.32434E but see under habitat, 20 June 2015, Graeme Smith, ♂ ( HW 1.75 ) on two slides (K.261268).

Diagnosis. This species can easily be distinguished from other species of the genus with two posterior insertions on each side of the nota by the quite posterior location of the anterior trichobothrial area of the pronotum (0.48 vs 0.36–0.42) and from V. bingara n. sp. and V. bundjalung n. sp. also by the number of pairs of urostyli (six vs five).

Description. Large silverfish, thorax at pronotum about one third wider than abdomen which only tapers slightly posteriorly from about the fifth abdominal segment; appearance when live mottled grey with light coloured legs and distinctly annulated terminal filaments ( Fig. 5 ).

Body length (H+B) up to 12.9 mm; thorax length 3.8 mm or 29% of H+B; width up to 2.9 mm with pronotum slightly wider and longer than the meso- and metanota (Fig. 210); antennae not complete in preserved material but Fig. 5 about equal to H+B; terminal filaments long, at least 80% H+B.

Pigment brownish. Flagellum of antennae light brown with weak annulated rings, the darker regions becoming longer distally; pedicel and scape without pigment. Terminal filaments annulated darker brown with only half to all of the most distal annulus of a division lacking pigment distal to the ring of major macrochaetae; the lighter bands difficult to discern between the most distal divisions. Head with pigment around eyes and quite strongly along lateral margins between the eyes and the peri-antennal group of macrochaetae; the pigment not extending the full length of the peri-antennal group. Clypeus, labrum and mandibles without pigment. Maxillary palp with dark pigment evenly over most of the penultimate article except for the length of the ventral face, third article with similar dark pigment dorsally but with wider pigment-free area than on penultimate article; slight pigment dorsally along dorsal face of second and third articles. Labial palp almost free of pigment with just a faint patch proximally on the outer margin of the distal article and along the outer margin of the penultimate article. Subcoxae, coxae and trochanter without pigment, femur with small areas of dark pigment distally on the leading edge and also on the bulge on the posterior margin, tibia with dark pigment on the outer margin of PIII but restricted to the distal end on PI and PII, first tarsal article pigmented except for its distal apex and its basal third. Urotergite X and coxites IX not pigmented. Styli IX with moderate pigment distributed evenly, other styli only very slightly pigmented.

Macrochaetae smooth, straw coloured to hyaline, apically bifurcate, some with truncated tips to each bifurcation (Fig. 211), others with minute bifurcations. Some macrochaetae on tibia, stout carrot-shaped (Fig. 212). The more anterior lateral insertion point of the posterior combs of the nota, at least on the pro and meso-nota with a long, thin trichobothrium-like seta.

Round scales variable in size, some as wide as long, others longer than wide (Fig. 213), mostly hyaline ventrally, dorsal scales with light brown ribs. Hyaline triangular scales present on femora and tibia (Fig. 214), pedicel (possibly some lanceolate) and scape, second article of maxillary palp and on styli IX. Clypeus with triangular and narrow triangular scales, some of which have straight ends and others more serrated. Scales present on the basal divisions of the terminal filaments but the density of setae along the edges makes this difficult to determine the arrangement; at least some of these scales approach lanceolate shape but do not appear to have a pointed apex and are probably best described as narrow tapering triangular scales.

Head wider than long (Fig. 215), without distinct bushes. Frons with glabrous anterior margin, the scales overhanging the anterior margin, lateral margin with dense strong macrochaetae about three to four rows wide behind the antennae reducing to a single row of 7–9 macrochaetae along to the antero-lateral corner, the peri-antennal group of about 12 macrochaetae with three cilia and a long thin trichobothrium at the mediad end. Clypeus quite reduced and folded back somewhat under the anterior margin of the frons, with some strong macrochaetae numerous cilia and setulae as well as triangular scales of varying width across the face. Labrum short with many strong macrochaetae distributed across the proximal half and some smaller setae in the anterior half.

FIGURES 210–223. Visma advenum n. sp. holotype ♂ 210. Habitus, antennae incomplete. 211. Macrochaeta of frons. 212. Carrot-shaped macrochaeta of tibia PI. 213. Round scale of pronotum. 214. Triangular scale of femur PI. 215. Head (crosshatched area obscured by eye pigment). 216. Antenna, scape, pedicel and basal intervals of flagellum. 217. Idem, most distal surviving interval showing possible minute basiconic sensillum (bs B). 218. Mandible. 219. Idem, incisor and molar regions. 220. Maxilla, smaller setae omitted from palp. 221. Idem, ultimate article of palp with three papillae (p). 222. Labium. 223. Idem, palp. Scale bars: 0.1 mm unless otherwise indicated.

Scape and pedicel of antenna (Fig. 216) with scales on lateral faces, both with a subapical ring of strong setae and some cilia on the pedicel. First and second annuli of flagellum with two rows of setae with at least one small trichobothrium per row, third to eighth annuli with a single row including also some cilia, ninth annulus showing the beginning of division into two annuli per interval with just a few setae and cilia on the basal part of the interval, clearly divided into two annuli by the eleventh interval with the trichobothrium restricted to the most distal annulus; further subdivision visible by the thirteenth interval which are clearly separate annuli by the eighteenth; intervals beyond the 22nd interval lost. Most distal surviving intervals (probably about less than one quarter the length of the antenna) (Fig. 217) divided into repeated patterns of four annuli, each with two rings of fine setae, the most distal annulus of each division with at least one but probably three trichobothria, rod-like basiconic sensilla may or may not be present (a vague impression of a basiconic sensillum was seen in the distal annulus of two intervals but were not seen with any confidence).

Mandibles not well aligned in dissected material (Figs. 218, 219) robust with a well-developed incisor and smaller molar areas; a group of about six short robust macrochaetae and about 12 setae adjacent to the molar area and a bush of about 60 macrochaetae externally.

Maxilla (Fig. 220) with 1–3 thick apically bifurcate macrochaetae externally proximal to the palp; lacinia short and wide, with three strong teeth, one set further back than the other two, followed by about seven lamellate processes and a row of ten setae, galea with stronger setae proximally but otherwise with only short fine cilia; apical article of maxillary palp (Fig. 221) 5.2 times longer than wide and about the same length as the penultimate article, the ultimate article with three slender branched papillae with very short arms and possibly some basiconic sensilla (type B) near the apex, last two articles of palp with fine setae only, three basal articles with subapical rings of thicker setae.

Labium (Fig. 222) wider than long, postmentum with setae arranged in an irregular row across the anterior third, prementum with transverse and oblique groups of strong setae and with short curved setulae distally; apical article of labial palp (Fig. 223), wider than long (L/ W 0.8), especially medially, with five papillae of the compact type arranged alternately in a line which can be almost straight or slightly staggered with the second and fourth papillae slightly more proximal than the others, no other sensilla seen; distally with numerous fine short setae, those proximal and medial longer than those distal with many curled setae; penultimate article triangular, basal article with tuft of setae, some fairly strong.

Pronotum ( Fig. 224 ) with well-developed setal collar of short apically bifurcate macrochaetae and some small setulae and cilia; lateral margins with many strong macrochaetae, some setae as well as occasional cilia and about six submarginal macrochaetae. Anterior trichobothrium about half-way (0.48) along the margin not associated with a submarginal macrochaeta, with two setulae but otherwise without any special chaetotaxy. The posterior trichobothrium mediad of a deeply bifurcate submarginal macrochaeta associated with a setula and a cilium. Posterior margin with 1+1 pairs of macrochaetae, the more antero-lateral insertion consisting of a very thin trichobothrium-like seta (the other macrochaeta lost on both sides) each associated with two or three cilia and 1–2 setulae. Mesonotum ( Fig. 225 ) with similar lateral chaetotaxy to pronotum except 5–6 combs anterior to the anterior trichobothrial area are composed of two macrochaetae, most combs associated with 1–2 setulae posterior to the comb as well as two cilia; both trichobothrial areas are more posterior, the anterior trichobothrial area with a macrochaeta mediad of the trichobothrium and the posterior area as in the pronotum; the 1+1 posterior combs consist of two insertion points. Metanotum ( Fig. 226 ) similar to mesonotum except the anterior trichobothrial areas even further posterior (about 0.8) and lacking the macrochaeta mediad of the trichobothrium; the 1+1 posterior combs consist of two insertion points.

Presternum narrow, with dense transverse row of strong macrochaetae ( Fig. 227 ). All thoracic sterna free with hyaline round scales. Prothoracic sternum large trapezoidal (L/ W 0.96) with fine setae along the whole length of the lateral margins, posterior corners each with three large setae slightly back from the margins, glabrous along the posterior margin, about as wide at base as long. Mesosternum ( Figs. 228 ) also trapezoidal just slightly wider than long, with 1+1 combs of three macrochaetae submarginally in the posterolateral corners with a largely glabrous region between, fine setae and some cilia along the posterior half of the outer margins. Metasternum ( Fig. 229 ) trapezoidal with glabrous concave margin between the 1+1 small posterolateral combs each of three small macrochaetae, about 1.4 times wider than long (L/ W 0.68), posterior half of lateral margins with numerous fine setae and some cilia.

Legs ( Figs. 227–229 ) progressively longer anterior to posterior with the tibia of PII being 1.2 times longer than that of PI and the tibia of PIII being 1.9 times longer than that of PI. Tibia L/W ratio of legs PI 2.9, PII 2.9, PIII 4.7; tarsi L/W ratio PI 7.8, PII 9.3, PIII 10.5. Precoxa of PI ( Fig. 227 ) with comb of about six macrochaetae on the laterad corner. Coxa of PI without comb in anterior “shoulder” position. Outer margin with numerous long macrochaetae in row two to three macrochaetae wide, becoming shorter distally; inner margin with about four short strong setae distally over the articulation and about three stronger setae spaced along the distal third of this margin along with smaller fine setae. Trochanter with some fine setae as well as three stronger setae and a short macrochaeta. Femur ventrally with several macrochaetae along the posterior margin and another midway along the anterior margin, distal anterior corner with about seven setae and macrochaetae subdistally arranged in two groups over the articulation and a line of several setae subdistally on the ventral face, ventral surface with fine setae in the posterior thirds while the rest is covered with a dense layer of triangular scales which are very prominent along the anterior margin. Tibia with a strong carrot-shaped macrochaeta distally which is only about half the size of the apical spur as well as several smaller strong setae along the ventral margin, dorsal or outer margin with two macrochaetae almost equally spaced along the length; apical spur distinctly hooked and bearing several small setae; face of tibia also with setae, some quite long as well as numerous triangular scales interspersed among the setae. Tarsi of four articles, the basal tarsal article of PI not quite as long as the remaining articles together, bearing some stronger setae below and numerous smaller setae; second and third articles particularly short with two long setae as well as several smaller setae, the second article of all legs with a long trichobothrium. Pretarsus with two long curved lateral claws and a much shorter straight medial claw. PII ( Fig. 228 ) and PIII ( Fig. 229 ) similar to PI except first tarsal article on PIII about equal to the other three together, tibia of PIII with long thin trichobothrium-like seta, more than twice as long as the tibia is wide, near the proximal macrochaeta on the dorsal surface.

Urotergite I with 2+2 combs (lacking submedial), each comb of three macrochaetae associated with one larger marginal seta, 3–6 setulae and 2–4 cilia. Urotergites II–VII with 3+3 small combs as shown in table 7, each lateral comb associated with 1–3 marginal setae, 3–5 cilia usually anterior to and between the insertions and 3–9 setulae between the combs and the margins, each sublateral comb with 1–3 setae, 2–5 cilia and 1–3 setulae, each submedial comb with 1–2 setae, two cilia and 0–2 setulae ( Figs. 230–233 ); urotergite VIII with 2+2 combs, lacking the sublateral comb, each lateral comb associated with 3–4 marginal setae, four cilia and 3–6 setulae; urotergite IX without combs but with 4–5 setulae and 2–3 cilia in each infralateral corner ( Figs. 234, 235 ). Urotergite X ( Fig. 236 ) round, short (L/ W 0.39) with numerous macrochaetae, setae and cilia along the lateral margins, posterior margin glabrous in the middle, lacking posterolateral macrochaetae.

Urosternite I glabrous, urosternites II–III with 1+1 lateral macrochaetae each associated with 1–2 cilia and two marginal setulae, urosternites IV–VIII with 1+1 lateral combs of a single macrochaeta mediad to each stylus ( Fig. 237 ), each macrochaeta associated with 1–2 marginal setae, 1–2 cilia and 2–10 setulae, the corner laterad to the styli with 1–2 marginal setae, a cilium and 0–2 setulae; the posterior margins of urosternites IV–VIII slightly concave, the posterior margin of urosternite VIII distinctly convex. Six pairs of styli present (on urosternites IV–IX), those on segments IV–VIII less than half the length of the styli on coxites IX, but still armed with several strong setae apically ( Fig. 238 ).

Each coxite IX ( Fig. 239 ) of male with numerous strong macrochaetae with small bifurcated tips along the inner and outer margins of the inner process and apically plus laterally on the outer process; the internal process acute, about 1.3 times longer than wide at its base and 3.1 times as long as the outer process which is shorter than wide at its base (L/ W 0.8). Styli IX long with several stronger setae distally and along the shaft, these setae not longer than the stylus width, the stylus (excluding the apical macrochaetae) about two and a half times the length of the internal process. Penis typical with numerous glandular setae apically, each set on a protuberance. Parameres long, conical with about 40 long thin setae.

Cerci ( Figs. 240, 241 ) with seven basal divisions shorter than wide then progressively longer with one ring of setae, macrochaetae, cilia and trichobothria in the third and fourth divisions, two in the second, fifth and sixth, then four from the eighth, narrow triangular and lanceolate scales present in all rings except the most apical. Seven or more rings per division from the 12 th, the number of these rings/annuli increasing progressively so that there are 16 in the most distal divisions. Trichobothria visible at least until the sixteenth division in the third most basal of about 12 rings and in the ninth ring of sixteen distal annuli. Median dorsal appendage ( Figs. 240, 242 ) with first two divisions covered by the epiproct, the next two divisions shorter with only a single ring of long setae, next three divisions increasingly longer with two rings, with lanceolate scales in the basal ring, at least laterally, a further annulus mostly with lanceolate scales appears in the following division and a fourth, also with narrow triangular scales in the ninth division, four rings per division by the ninth increasing to fourteen in the most distal survive divisions (23 rd) these distal divisions with trichobothria on the 4 th and 9 th rings and large macrochaetae on the 7 th and 14 th rings; scales do not appear to be present in distal half of median dorsal appendage.

Female unknown.

Habitat. Collected as it emerged from a crack in the end of a piece of firewood. This piece of wood had been brought to this area by campers and its origin is unknown.

Etymology. Named from the Latin noun for foreigner or immigrant referring to the belief that this specimen was accidently imported to its type locality.

Figures

FIGURES 5–9. 5. Visma advenum n. sp. 6. Visma bundjalung n. sp. 7. Visma bingara n. sp. 8. Visma powellheueri n. sp. 9. Visma xanthorrhoea n. sp.

FIGURES 224–227. Visma advenum n. sp. holotype ♂ 224. Pronotum, anterior and right margins. 225. Mesonotum, right mar- gin. 226. Metanotum, right margin. 227. Presternum, prothoracic sternum and PI. Scales: 0.1 mm.

FIGURES 228–236. Visma advenum n. sp. holotype ♂ 228. Mesothoracic sternum and PII. 229. Metathoracic sternum and PIII. 230. Urotergite VI. 231. Idem, left lateral comb. 232. Idem, left sublateral comb. 233. Idem, left submedial comb. 234. Urotergite IX. 235 Idem, right infralateral comb. 236. Urotergite X. Scales: 0.1 mm.

FIGURES 237–242. Visma advenum n. sp. holotype ♂ 237. Urosternite VII and most of right side of urosternite VIII. 238. Detail of stylus VII. 239. Coxites IX, styli, parameres and penis. 240. Base of cercus and median dorsal appendage. 241. Most distal surviving division of cercus. 242. Most distal surviving division of median dorsal appendage. Scales: 0.1 mm.