Heterolepisma heraldense, Smith & Mitchell, 2019

Smith, Graeme B. & Mitchell, Andrew, 2019, Species of Heterolepismatinae (Zygentoma: Lepismatidae) Found on some Remote Eastern Australian Islands, Records of the Australian Museum 71 (4), pp. 139-181 : 164-170

Heterolepisma heraldense sp. nov.

http://zoobank.org/NomenclaturalActs/ BA3F 1745-78 BD-407A-9689-147387B73842

Figs 127–168

Holotype. ♀ ( HW 1.00) ( AM K.261309 on one slide) CORAL SEA TERRITORY: South West Herald Cay , 16.98°S 149.13°E, 17.v.2007, R. Farrow . Paratypes. juvenile ♂ ( HW 0.80) (K.261310 on one slide) same data as holotype; juvenile ♀ ( HW 0.70) (K. 377828 in alcohol) CORAL SEA TERRITORY: North East Herald Cay , 16.943°S 149.199°E, 16.v.2007, P. Greenslade & R. Farrow .

Diagnosis. As for H. pyramidum sp. nov., described above, from which it can easily be distinguished by its smaller size (6 mm for an apparently mature female vs almost 9 mm for an apparently subadult female), the posterior combs of the nota (but not the urotergites) which each consist of a larger macrochaeta and a sizable, but smaller, submarginal insertion (compared to just a single macrochaeta), the location of the anterior trichobothrial areas of the meso- and metanota about ¾ the distance along the margins (versus 5/6), the smaller number of combs of two macrochaetae on the lateral margins of the meso- and metanota (three and two versus two and one respectively), the shorter wider legs (e.g., femur PII L/ W 1.8 versus 2.4 and tarsi PIII L/ W 6.1 versus 9.2), the presence of 3+3 combs on urotergite I (versus 2+2) and the smaller number of divisions in the ovipositor (circa 37 versus circa 45).

This species may however eventually prove to be a synonym of H. rouxi Silvestri, 1915 for which the original description is inadequate.

Description

Appearance: Small to medium sized silverfish, thorax about 7% wider than abdomen which only tapers slightly posteriorly from about the fifth abdominal segment ( Fig. 127 ); appearance when live unknown.

Body length: H+B 5.9 mm; HW 1.00 mm; thorax: length 1.9 mm or 0.32 H+B; width up to 1.45 mm, meso- and nota of same width with the pronotum just slightly narrower, pronotum longer than meso- and metanota; antennae incomplete at 4.1 mm or> 0.7 H+B; cerci and median dorsal appendage largely damaged at 1.9 mm and 0.7mm (>0.32 and>0.12 H+B) respectively.

Pigmentation: Pigment brownish. Flagellum of antennae evenly pale becoming slightly darker distally; pedicel and scape without pigment. Terminal filaments annulated darker brown with only the most distal portion of each major division from just below the rosette of major macrochaetae to the suture with the next division devoid of pigment. Head with very small area of pigment around eyes only. Clypeus, labrum and mandibles without pigment. Maxillary palp without pigment except for slightly darker penultimate article. Labium and labial palp largely without pigment except for small amount along the outer margin of the penultimate article. Legs without pigment except for dorsal face of the tibia and the first tarsal article where light pigment is fairly evenly distributed. Urotergite X with light pigment, darkest proximally and becoming lighter distally. Sternites including coxites IX and styli without obvious pigment. Ovipositor without pigment.

Macrochaetae: Smooth, hyaline or slightly straw coloured, apically bifurcate with truncated tips to each bifurcation. Some macrochaetae on tibia, stout carrot-shaped.

Scales: Quite broad, brown with numerous subparallel ribs that do not surpass the margin of the scale ( Fig. 128 ). Scales found on top of head; scales absent from clypeus and labrum as well as all cephalic appendages; dark scales present on all nota and abdominal tergites, clear scales on all thoracic and abdominal sterna, and coxae of legs, absent from styli. Lanceolate scales present on all femora and tibia; other leg articles without scales; lanceolate scales not unambiguously observed on basal third of the terminal filaments.

Head: Wider than long ( Fig. 129 ), without distinct bushes. Anterior margin without macrochaetae except for two or three tiny setae in the middle; strong macrochaetae along lateral margins with peri-antennal groups of two or three larger macrochaetae as well as some cilia, only weakly connected with the one to two rows of macrochaetae along the margin, the marginal macrochaetae continue along the sides of the head behind the antennae with a line of four or five macrochaetae lying above the eyes. Clypeus with some longer macrochaetae in 1+1 rows of about three macrochaetae laterally and close to the frons as well as numerous setae across the face; lanceolate scales not observed. Labrum with many setae across the middle of the face a line of six thinner setae anteriorly. — Scape ( Fig. 130 ) quite short with a subdistal line of setae and smaller setae over the dorsal anterior face, pedicel short, also with a subapical rosette of small macrochaetae with a few setae scattered over the surface medially; first annulus of flagellum with a subapical rosette of fine setae, subsequent annuli with a single rosette of setae, the divisions between the annuli difficult to discern in the slide mounted material, the intervals split into two annuli by the 7–9th interval. Most distal surviving intervals ( Fig. 131 ) divided into repeated patterns of four or possibly eight annuli, the basal interval with a single rosette of small fine setae, the second and third with two similar rosettes, the ultimate article of each interval with two rosettes of small setae and a further subapical rosette of fine, curved-tipped setae and one or two basiconic sensilla (type B). Trichobothria were rarely observed in the most apical rosettes of each interval making it difficult to determine the number of annuli per interval. — Mandibles ( Fig. 132 ) aligned on slide so that the molar areas of both mandibles are difficult to discern but appear to be typical for Heterolepismatinae with well-developed molar and incisor areas; a group of about seven strong and short plus four thinner, apically bifurcated setae distally adjacent to the molar region and a bush of about 60 macrochaetae externally. — Maxilla ( Figs 133, 134 ) with three apically bifurcate macrochaetae externally proximal to the palp; lacinia short with three strong teeth, one set further back than the other two, followed by about seven lamellate processes and a row of eight setae, galea with short fine setulae as well as two or three setae basally; apical article of maxillary palp ( Fig. 135 ) only 2.9 times longer than wide (range 2.1–4.0) and 1.3 times longer than the penultimate article (range 1.1–1.5), the ultimate article with three branched papillae, other specialised sensilla (e.g., basiconic sensilla) not seen, last two articles of palp with fine setae only, two basal articles with subapical rosettes of thicker setae, third article also with rosette but setae not as thick as those on two basal articles. — Labium ( Fig. 136 ) much wider than long, postmentum with fine setae along the lateral margins and longer slightly strong thin simple setae scattered in band across entire width anteriorly, prementum with transverse and oblique groups of strong simple setae and with short setulae distally; apical article of labial palp, about as wide as long (range L/ W 0.95 –1.12), covered with numerous fine short setae, with five papillae of the compact type arranged in a three plus two cluster arrangement, the distal three arranged in a curved line, a small single basiconic sensillum (type C) on the outer margin proximal to the level of the papillae; penultimate article with some longer but not much stronger setae on the bulge medially; second article also with similar setae; basal article with smaller setae only.

Thorax: Pronotum ( Fig. 137 ) with complete setal collar of short macrochaetae and some cilia; lateral margins with marginal setae as well as cilia and two submarginal macrochaetae, one about ¼ the distance along the margin and the other about ⅞ along the margin associated with the posterior trichobothrial area. Anterior trichobothrium a little further than half way along the margin with two or three setulae laterad and posterior to the trichobothrium, not associated with a macrochaeta ( Fig. 138 ). The posterior trichobothrium mediad of a submarginal macrochaeta and its cilium, with two or three setulae posterior to this group ( Fig. 138 ). Posterior margin with 1+1 combs composed of one larger macrochaeta insertion associated with two cilia and a smaller seta insertion posterior and mediad of the larger macrochaeta ( Fig. 139 ). — Mesonotum ( Fig. 140 ) also with small setae along the margins as well as two combs each of two macrochaetae anterior to the anterior trichobothrial area; the more medial macrochaeta only half the length of the outer macrochaeta. Both trichobothrial areas are more posterior than on the pronotum ( Fig. 141 ), the anterior trichobothrium located about ¾ the distance along the margin not associated with any macrochaeta and the posterior area as in the pronotum; 1+1 posterior macrochaetae as in pronotum. — Metanotum ( Figs 142, 143 ) similar to mesonotum but with only a single comb of two macrochaetae.

Presternum with transverse row of setae and cilia across the entire width, the middle region with strong macrochaetae ( Fig. 144 ). All thoracic sterna with hyaline round scales. — Prothoracic sternum ( Fig. 144 ) cordiform with distinct concave margins in distal half as well as being longitudinally slightly concave, slightly wider than long (L/ W 0.86), 1+1 irregular combs of six bifurcate macrochaetae running subparallel to the margin, as well as some marginal setae and cilia in distal three quarters. — Mesosternum ( Figs 146 ) sub-parabolic as long as wide at its base, (L/ W 1.03) with about six macrochaetae forming an irregular submarginal row along the posterior quarter of the margin, short straight posterior margin between combs. — Metasternum ( Fig. 147 ) wider than long (L/ W 0.80), apically round, 1+1 apical combs of five or six macrochaetae, the distance between the combs two to three times the average length of each comb (range 2.2–3.0), lateral margins with a few simple setae and cilia only adjacent to the combs.

Legs ( Figs 144–147 ), PI lost beyond trochanter in holotype but legs becoming progressively long tibia PI / PIII of juvenile paratypes 0.64, tarsi PI / PIII 0.76; tibia L/W ratio of legs PI 2.4 (range 2.3–2.6), PII 2.6 (range 2.3–2.8), PIII 3.3 (range 2.8–3.6); tarsi L/W ratio PI 5.3 (range 4.8–5.8), PII 5.1 (range 4.9–5.4), PIII 6.1 (range 5.6–6.3). Precoxa of PI with lateral combs of four macrochaetae. — Coxa of PI ( Figs 144, 145 ) with ill-defined comb of two macrochaetae near the anterolateral corners, many strong macrochaetae in approximately two rows along the external margin, becoming shorter distally; inner margin with about five short macrochaetae distally over the articulation and another robust seta subdistally near three long thin seta on the dorsal face. — Trochanter with two or three stronger setae as well as small setae and setulae. — Femur quite broad (L/ W 1.8 –2.0) ventrally with two large macrochaetae near the trochanter and four large macrochaetae on the posterior bulge with two equally spaced macrochaetae between these groups, subdistal anterior corner with two macrochaetae; three or four longer, strong setae along the posterior margin distal of the posterior bulge; lanceolate scales along the margin and extending onto the ventral face of the femur in the anterior half, rest of ventral surface with fine scattered setae. — Tibia may have a few lanceolate scales on the ventral face proximally but the quality of the material available makes it difficult to be certain, rest of surface with setae, a strong carrot-shaped macrochaeta distally, another pair just beyond midway along the margin, the presence of a smaller pair near the proximal end of the posterior margin cannot be determined, anterior margin probably with one or two stout macrochaetae about one third along the margin and another pair two thirds along the margin, as well as smaller setae; apical spine with several setae. — Tarsi of four articles, the basal tarsal article of PI not quite as long as the remaining articles together, bearing some long, stronger setae below and many other smaller setae over the surface; second and third articles the shortest, each with two long, stronger setae ventrally. Pretarsus with two long curved lateral claws and a shorter straight medial claw. — PII ( Fig. 146 ), coxa similar to PI except with fewer macrochaetae along the outer margin, only becoming two macrochaetae wide in the distal half, with about five stout setae over the articulation, trochanter with simple, but long setae. Femur short and wide (L/ W 1.8) with about ten stout macrochaetae along the posterior margin as illustrated, lanceolate scales along the margin and extending onto the ventral face of the femur in the anterior half, rest of ventral surface with fine scattered setae. Tibia with a few lanceolate scales on the ventral face proximally, rest of surface with setae, with three stout macrochaetae along the dorsal margin and about five along the ventral margin. Tarsi quite short with long setae on the ventral surface, pretarsi with two long curved lateral claws and a shorter straight medial claw. — PIII ( Fig. 147 ) similar to PII, femur short and wide (L/ W 1.6 –1.7), the first tarsal article being almost two thirds the total length of the tarsus. Tibia with long thin trichobothrium-like seta arising from the dorsal margin just forward of the most proximal dorsal macrochaeta (only seen in paratype K.261310), the hair being almost twice the width of the tibia in length .

Abdomen: Urotergites I–VII ( Figs 148, 151 ) with 3+3 combs as shown in Table 8, although the submedial comb is absent on one side of urotergite I in the male paratype (K.261310), the lateral combs ( Figs 149, 152 ) consisting of 1–3 macrochaetae each associated with 2–3 cilia, 1–2 marginal setae and 1–2 setulae, the sublateral combs ( Figs 149, 153 ) of 1–3 macrochaetae each associated with 0–2 cilia, 1–2 marginal setae and 1–2 setulae, the submedial combs ( Figs 150, 154 ) with two cilia and a marginal seta; urotergite VIII with 2+2 combs, lacking the sublateral comb; urotergite IX ( Figs 155, 156 ) without combs but with three small marginal setae in each infralateral corner. Urotergite X ( Fig. 157 ) short and distinctly trapezoidal (L/W about 0.46), with 1+1 macrochaetae in the posterolateral corners and several setae along the margins.

Urosternite I with a medial comb of two macrochaetae associated with a cilium at each end and a marginal seta and setula on a non-protruding region ( Figs 158, 159 ); urosternites II–VI ( Figs 160, 161 ) with 1+1 lateral combs each of two to four macrochaetae and with a cilium at each end of the comb, one or two marginal setae and 1–2 setulae, the distance between each comb is about twelve times the average length of the combs on the segment (range 10 – 14), urosternite VII ( Fig 162 ) in ♀ with styli, 1+1 combs each of two or three macrochaetae located mediad of each stylus associated with a marginal seta and 2–3 marginal setulae, laterad of the stylus is a cilium associated with two marginal setulae. Urosternite VIII in ♀ divided into separate coxites shaped as shown in figure 163, each bearing a small stylus, 2–3 macrochaetae mediad of the stylus insertion associated with a few small marginal setae, with two or three setae and a cilium on the outer side of the stylus. Styli present in three pairs, those on IX about 1.5 times the length of those on VII.

Coxite IX of ♀ ( Fig. 163 ) with apically acute internal process, about four times longer than the external process in the adult and 1.5 times as long as wide at its base, reaching to about one quarter length of the stylus; external and internal margins of internal with a few moderately strong setae, apex of round outer process with three or four strong setae. — Ovipositor appears fully developed surpassing the end of the stylus by about the length of the stylus (1.9 HW), composed of about 37 divisions. Distal divisions of gonapophyses ( Fig. 164 ) with only short fine setae and setulae.

Cerci ( Fig. 165 ) with basal divisions wider than long, divisions two to four with a single rosette of setae cilia and some trichobothria, fifth and sixth divisions each with two rosettes, the basal rosette of finer setae and trichobothria, following divisions consisting of three then four rosettes; most distal surviving divisions (probably only one third the length of the cercus) composed of four annuli each with two rosettes of setae, with large macrochaetae restricted to the most distal rosette. — Median dorsal appendage ( Fig. 166 ) not well preserved; only about seven divisions remaining, most setae quite long and thin, macrochaetae restricted to the most distal rosette of each division. Lanceolate scales not observed on the terminal filaments.

Male: Based on specimen K.261310 which may be subadult: As for female but styli present only on segments VIII and IX, coxites IX ( Fig. 167 ) with acute inner process about as long as wide at its base (range 0.95–1.04) and 1.8–2.7 times longer than the external process, reaching to just under half the length of the stylus; both processes also with several strong setae mostly apically emerging from both the dorsal and ventral surfaces of the processes close to or on the margin. Parameres a little shorter than wide, with only about ten short fine setae ( Figs 167, 168 ). Penis typical for genus with numerous glandular setae apically, each set on a protuberance.

Habitat. The specimens were collected from both low coral cays that form the Herald Group. The specimen from NE Cay (K.377828) was extracted from Abutilon [fam. Malvaceae ] leaf litter using a Tullgren funnel. The specimens from the SW Cay were labelled “HC S bark”.

Etymology. The species named heraldense referring to the type locality.

Remarks

Silvestri’s 1915 description of the New Caledonian species H. rouxi , while diagnostically useful at the time it was written, is today inadequate. It lacks not only higher level details such as the chaetotaxy of the anterior margin of the frons and the presence or absence of lanceolate scales but also many smaller details such as the number of divisions in the ovipositor and the chaetotaxy of the lateral margins of the nota which could well reveal differences. Heterolepisma heraldense sp. nov. may eventually prove to be conspecific with H. rouxi although the illustrated urotergite X in the latter appears more rounded in the male. New Caledonia is some 1600 km south east of the Herald Cays.

Figures

Figures 127–136. Heterolepisma heraldense sp. nov. holotype specimen K.261309 ♀ (127) habitus; (128) scale from urotergite VII; (129) head (cross-hatched area obscured by eye pigment); (130) antenna, scape, pedicel and basal intervals of flagellum; (131) idem, most distal surviving interval showing basiconic sensilla (bsB); (132) mandible (poorly orientated); (133) maxilla, only more prominent setae of palp illustrated; (134) idem, lacinia; (135) idem, ultimate article of palp with its three branched papillae (bp); (136) labium. Scale bars = 0.1 mm unless otherwise indicated.

Figures 137–145. Heterolepisma heraldense sp. nov. holotype ♀ specimen K.261309 unless otherwise noted by specimen number (137) pronotum; (138) idem, trichobothrial areas of left side; (139) idem, left posterior comb; (140) mesonotum, right side; (141) idem, trichobothrial areas, left side; (142) metanotum, right side; (143) idem, trichobothrial areas, left side; (144) presternum, prothoracic sternum and coxa of PI; (145) PI of K.261310. Scale bars = 0.1 mm.

Figures 146–161. Heterolepisma heraldense sp. nov. holotype ♀ specimen K.261309 (146) PII and mesothoracic sternum; (147) PIII and metathoracic sternum; (148) urotergite I; (149) idem, right lateral and sublateral combs; (150) idem, right posterior comb; (151) urotergite VII; (152) right lateral comb of urotergite IV; (153) right sublateral comb of urotergite IV; (154) right submedial comb of urotergite IV; (155) urotergite IX, right side; (156) idem, detail of infralateral comb; (157) urotergite X; (158) urosternite I; (159) idem, medial comb; (160) urosternite III; (161) idem, left comb. Scale bars = 0.1 mm.

Figures 162–168. Heterolepisma heraldense sp. nov. holotype ♀ specimen K.261309 unless otherwise noted by specimen number (162) urosternite VII with styli; (163) right coxites VIII and IX, with stylus IX and ovipositor; (164) apex of ovipositor valves; (165) base of cerci; (166) base of medial dorsal appendage; (167) coxites IX of ♂ K.261310; (168) left paramere. Scale bars = 0.1 mm.