Heterolepisma coorongooba, Smith & Mitchell & Lee & Espinasa, 2019

Smith, Graeme B., Mitchell, Andrew, Lee, Timothy R. C. & Espinasa, Luis, 2019, DNA Barcoding and Integrative Taxonomy of the Heterolepisma sclerophylla species complex (Zygentoma: Lepismatidae: Heterolepismatinae) and the Description of Two New Species, Records of the Australian Museum 71 (1), pp. 1-32 : 16-22

Heterolepisma coorongooba sp. nov.

Figs 6 , 8–36

Holotype. ♀ ( HW 1.30 ) ( AMS K.261208, K.261209 on two slides) NSW: Glen Davis, above Coorongooba campground, 33.1271°S 150.3232°E 313m asl, 20.vi.2015, Graeme Smith . Paratypes. 2♀♀, 1♂, 1 juvenile, all same data as holotype including 1♀ ( HW 1.15 ) ( AMS K.261210, K.261211 on two slides) ; 1♀ ( HW 1.11 ) ( AMS K.261212, K.261213 on two slides) ; 1♂ ( HW 1.08 ) ( AMS K.261204, K.261205 on two slides) ; 1 juvenile ( HW 0 3) ( AMS K. 377726 in ethanol) .

Diagnosis. This species is very similar to Heterolepisma sclerophylla differing in having one fewer pairs of styli in both the male and female (i.e. IX only in ♂, VIII and IX in the ♀). Compared to the lineage from the type locality it also has a longer ovipositor and thicker and perhaps more densely packed chaetotaxy along the pronotal collar and margins of the head.

Description

Appearance: Medium to large silverfish, scale covering in life uniform or slightly mottled grey with brown antennae, terminal filaments brown with lighter annuli around larger macrochaetae resulting in distinctly banded appearance ( Fig. 6 ).

Body length: H+B up to 9.1 mm (♀) 7.0 mm (♂); maximum HW 1.30 mm; thorax: length up to 2.5 mm (or 0.27–0.36 H+B); width up to 2.05 mm, usually slightly widest at the mesonotum; antennae damaged in all specimens, maximum preserved length of antenna 4.4 mm (or 0.56 H+B); terminal filaments damaged in all specimens, maximum preserved length of cercus 2.8 mm (or 0.31 H+B); maximum preserved length of median dorsal appendage 3.4 mm (or 0.42 H+B). Body neither elongate nor broad with thorax slightly wider than abdominal segment I, the following abdominal segments about the same width until the fourth or fifth after which the abdomen tapers posteriorly.

Pigmentation: Pigment brown in alcohol preserved specimens. Present around eyes and to a lesser extent behind the peri-antennal group of macrochaetae; pedicel and scape very lightly pigmented distally, rest of flagellum uniformly lightly pigmented; all articles of maxillary palp with pigment especially in the four most distal articles although much less in the ultimate article; labium with pigment on the three most distal articles, being strongest on the penultimate, especially distally. Pigment present in anterior corner and along margins of all nota. Legs not heavily pigmented, with light pigment along outer margin of the coxa and the trochanter, apically on the outer femur and strongest on the tibia especially on the dorsal surface, present on basal article of tarsi, urotergite X and coxites IX with light pigmentation; styli IX pigmented in distal three quarters; other styli with less pigment. Ovipositor with yellowish hue. Terminal filaments with rings of pigment, with the pigment present in all annuli except the annuli bearing the large macrochaetae. Pigmentation is much reduced in juvenile specimens.

Macrochaetae: Bifid apically, or simple, light to darker brown in colour. Often quite thick e.g., the stronger macrochaetae of the pronotal collar measured about 50 microns in diameter in the holotype ( HW 1.30 ) compared to 38 microns in the similar-sized holotype of H. sclerophylla ( HW 1.28 ) from Broulee (compare Figs 7, 8 ). They also appear to be more densely packed .

Scales: Unevenly rounded or ovoid, with numerous parallel ribs that do not extend beyond the margin ( Fig. 9 ); in alcohol dorsal scales with dark brown ribs; ventrally mostly hyaline. Lanceolate scales not observed. Scales absent from flagellum of antennae, mouthparts and terminal filaments.

Head: Wider than long ( Fig. 10 ) with marginal rows about three macrochaetae wide along the sides of the vertex decreasing to two wide in front of the antennae and six strong curved macrochaetae along the anterior margin, the lateral rows extend back above the eyes, as well as a small 1+1 peri-antennal groups not quite isolated from the marginal rows at the level of each antenna. Clypeus with numerous setae, some long and thin, others more robust arranged in 1+1 lines in the proximal lateral regions but not forming combs. Labrum with thin setae only. Eyes dark, composed of about 12 ommatidia.—Antennal scape with a subdistal rosette of setae, very conspicuous from above ( Fig. 11 ), and numerous setae along the sides and over the ventral face; pedicel short, 0.51 times the length of the scape (range 0.47–0.55), with many setae mostly distally and on the ventral face; repeating intervals of distal end of antennae ( Fig. 12 ) of eight annuli, the most apical annulus of each interval (T-annulus) with a trichobothrium and at least one small inconspicuous rod-like basiconic sensillum (type B of Adel, 1984), the second and forth annuli also each with a sausage-shaped type C sensillum (confirmed also to be present on same annuli in holotype of H. sclerophylla ).—Mandibles typical for genus with welldeveloped molar and incisor areas; a group of about nine strong setae distally adjacent to the pectinate molar area and a bush of 50+ setae and macrochaetae externally.—Maxilla ( Fig. 13 ) with three large macrochaetae externally proximal to the palp, the lacinia with three strong teeth, one shorter than the rest, seven lamellate processes and a row of eight simple setae, the galea longer than the lacinia with setulae on the outer face. Palp with rosettes of distinctly stronger setae (some “carrot-shaped”) subapically on the three basal articles, all articles with numerous fine setae, apical article of maxillary palp 4.6 times longer than wide (range 4.1–4.9) and 1.23 times longer than penultimate article (range 1.16–1.27), the ultimate article in both sexes with three “branched” papillae, those in the female less robust than those in the male.—Labium ( Fig. 14 ) short and broad with rows of strong setae on the prementum and submentum; glossae and paraglossae quite broad with short curved setulae; labial palp short, apical article eccentric suboval, 1.1 times as long as wide (range L/W 0.8–1.3) with 2+3 papillae of compact type in a “cluster formation” where the slightly larger distal papillae curve around the two smaller proximal papillae and a curved club-like thin-walled basiconic sensillum and at least one rod-like basiconic sensillum, which can also be confirmed as present on the holotype of H. sclerophylla .

Thorax: Pronotum ( Fig. 15 ) with strong setal collar of short, apically bifurcated setae and cilia with a row of longer macrochaetae spaced along the back of the collar including 1+1 long thin simple setae about one third in from each side, the density and length of the smaller more marginal macrochaetae of the collar decreases only slightly towards the middle but not the size and density of the larger spaced macrochaetae in the posterior row; lateral margins also with numerous shorter but quite robust, apically bifurcate setae as well as several larger more erect submarginal macrochaetae; trichobothrial areas open and in contact with the lateral margins, the anterior one ( Fig. 16 ) located just anterior to the mid-point along the margin, with or without a large submarginal macrochaeta, when present laterad to the trichobothrium (this macrochaeta missing on the left side of the holotype) and with a cilium and a few setulae; posterior trichobothrial area ( Fig. 17 ) near posterior lateral corner with two submarginal macrochaetae between the trichobothrium and the margin as well as a few setae and setulae; posterior margin slightly concave with 1+1 combs ( Fig. 18 ) each of two macrochaetae, the more postero-mediad lying flatter than the other, each comb associated with a setula and a few cilia.—Mesonotum with lateral chaetotaxy similar to pronotum but less dense ( Fig. 19 ), except the submarginal macrochaetae anterior to the trichobothrial areas are grouped into combs of two, each associated with a cilium and a few setulae, the more posterior of these on the left side of the holotype of only one macrochaeta, both trichobothrial areas ( Fig. 20 ) of similar configuration to those of pronotum except anterior area has a macrochaeta mediad of the trichobothrium. The posterior combs of the mesonotum are unusual in that they both consist of only a single macrochaeta in the illustrated holotype ( Fig. 21 ) whereas in the paratype K. 261204 one consists of two macrochaetae and the other of only one and in the other paratypes (K. 261213 and K. 261210) two macrochaetae are present on both sides.—Metanotum ( Figs 22, 23 ) similar to mesonotum; both posterior combs consist of two equal sized insertion points. The trichobothrium appears to be absent from the right posterior area of the holotype.

Presternum narrow, with transverse row of strong setae and numerous cilia and setulae ( Fig. 24 ).—All thoracic sterna and coxae with hyaline scales. Prothoracic sternum pointed cordiform, almost as long as wide at its base (range L/W 0.91–1.00) and reaching to about two thirds the length of the coxa, rounded apically and with a medial furrow ( Fig. 24 ), most of lateral margins with numerous small marginal setae and cilia, with 6–7 larger submarginal macrochaetae forming weak combs parallel to the edges in the distal third.—Mesosternum ( Fig. 25 ) 1.08 times longer than broad (range 1.01–1.12) with an acutely rounded apex, with setae and cilia along the distal quarter of the margins, with 1+1 distal combs of four apically bifurcate macrochaetae and 1+1 subposterior more pointed macrochaetae.—Metasternum ( Fig. 26 ) 0.79 times longer than wide (range 0.77–0.80) with less pointed, even slightly concave, apex, each comb of four macrochaetae.

Legs fairly long ( Figs 24, 26 ), tibia L/W ratio of legs PI 3.0 (range 2.9–3.2), PII 3.4 (range 2.8–4.0), PIII 3.9 (range 3.5–4.2); tarsi L/W ratio PI 7.0 (range 6.3–8.0), PII 7.0 (range 6.3–7.7), PIII 8.5 (range 7.4–9.7). Legs increasingly longer from front to back, mean ratio PI/PIII (tibia 0.62, tarsus 0.72). PI with transverse comb of about six macrochaetae laterally on the precoxa. Coxa of all legs covered with hyaline scales and with strong macrochaetae and numerous cilia and setulae in a row about two macrochaetae wide along the external margin, a strong seta on the inner margin subapically and group of about six curved setae at the apex over the articulation. Trochanter lacking scales, with fine and one stronger seta over the surface. Femur with numerous setae over most of the surface and along the margin; anterior distal end with two strong, quite deeply bifurcate stout macrochaetae and another simple stout macrochaeta more proximal; posterior margin with several strong macrochaetae as illustrated. Tibia with numerous long setae over the ventral surface, with three stout macrochaetae on or near the anterior margin and six or seven stout macrochaetae along the posterior margin; apical spur with several setae. Tibia of PIII with a long thin, laterally projecting trichobothria-like seta inserted dorsal to the proximal stout macrochaeta on the anterior margin, which is about two times as long as the tibia is wide. Tarsus with four articles, all with numerous setae, some on the ventral surface quite long and strong. Pretarsus with long curved lateral claws and a strong curved shorter medial claw.

Abdomen: Urotergite I usually with 2+2 combs each of one to three macrochaetae (usually two) located quite close together, urotergites II-VII with 3+3 combs of macrochaetae as in Table 7 ( Figs 9 , 27–29 ) noting that the more posteromedial insertion point of each submedial comb was occasionally, quite a bit smaller than the other insertion point, but mostly of about the same size; each comb also associated with up to five marginal setae, five setulae and four cilia. Urotergite VIII with 2+2 combs, lacking the sublateral comb; urotergite IX ( Fig. 30 ) with two infralateral setae on each side as well as a setula and a few cilia. Urotergite X short, parabolic in both sexes ( Fig. 31 ), L/W at base about 0.52 (range 0.51–0.55) with many strong setae along entire margin and obscure 1+1 submarginal macrochaetae in the posterolateral corners.

Urosternite I glabrous, urosternites II–VIII ( Fig. 32 ) with 1+1 single macrochaetae ( Fig. 33 ), each associated with 0–2 small marginal setae as well as a few cilia and/or setulae. Coxites of segment VIII in ♀ ( Fig. 34 ) with one or two small macrochaetae, one or two small marginal setae and a cilium mediad of the stylus base and some small setae, setulae and a cilium laterad of the stylus base. Styli in two pairs in the ♀ (VIII–IX); all styli with several noticeably longer and stronger setae apically ( Fig. 34 ) as well as stronger setae along the middle of the ventral face. Styli IX 2.4 times as long as styli VIII (range 2.2–2.8).

Coxite IX of ♀ ( Fig. 34 ), the internal process acute apically, about three times longer than the external process (range 2.9–3.2) and 1.5 times as long as broad at its base (range 1.5–1.6), not reaching to half the length of the stylus; external and internal margins of internal process and external margin and apex of outer process with many moderately strong setae directed both up and down.—Ovipositor ( Fig. 34 ), very long and thin (up to 2.34 HW), surpassing the apex of stylus IX by more than the length of the stylus (excluding terminal macrochaetae), composed of 34–39 divisions. Distal divisions of gonapophyses VIII and IX with only short fine setae and setulae.

Cerci not well preserved in slide material, with basal divisions shorter than long, gradually becoming longer distally, equally wide as long by about the eighth division after which they become even longer with more annuli each with a rosette of setae and some with trichobothria with the large macrochaetae restricted to the most distal annulus of each division; the most distal surviving divisions with up to four annuli, this annulus without pigment.—Medial filament of similar arrangement.

Male: As for female except only one pair of styli (segment IX). Coxites IX ( Fig. 35 ) with acute inner process about 1.3 times longer than wide at its base and about three times longer than the external process, reaching to just under half the length of the stylus. Both process 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 longer than wide, with about thirty fine setae ( Fig. 36 ). Penis typical for genus with numerous glandular setae apically, each set on a protuberance.

Subadult stages: the single juvenile specimen available, K.377726 (HW 0.63) had a single pair of styli (IX) and no indication of urosternite VIII dividing into separate coxites nor any nascent genitalia (ovipositor or parameres). The thoracic sternites conformed to those of the adults and the long thin setae on the tibia of PIII was present and very long (about three times the width of the tibia), tergite X was round but shorter than in the adults and the feathered papilla of the maxillary palp could not be seen.

Habitat. Heterolepisma coorongooba was collected from leaf litter protected from rain under a fallen but still elevated, log.

Etymology. The species name is derived from the proper noun Coorongooba referring the creek that flows through the valley from where it was collected.

Comments. The morphology of this species is very close to that of H. sclerophylla , differing from it only in the absence of the most anterior pair of styli in both sexes. It differs from the Broulee lineage in the length of the ovipositor (2.17–2.34 times HW versus 1.49–1.95), but not so much in the number of divisions (34–39 versus 32–37) and the more robust macrochaetae. The Megalong, North Nowra and Glenbrook lineages also have more robust macrochaetae and a longer ovipositor (but more divisions) leaving the fewer styli as the only unambiguous defining character.

Figures

Figure 6. Heterolepisma coorongooba sp. nov. Glen Davis, NSW.

Figures 7–14. Heterolepisma sclerophylla Smith and Heterolepisma coorongooba sp. nov. (7) Heterolepisma sclerophylla Smith, holotype ♀, medial section of pronotal collar. (8–14) Heterolepisma coorongooba sp. nov. holotype ♀ (8) medial section of pronotal collar; (9) lateral bristlecomb of urotergite III and adjacent scale; (10) head; (11) scape, pedicel and basal interval of flagellum, from above; (12) antenna, most distal surviving annuli; (13) maxilla, only larger setae of palp illustrated; (14) labium, setae of palp not strong so not illustrated. Scale bars = 0.1 mm.

Figures 15–23. Heterolepisma coorongooba sp. nov. holotype ♀ (15) left lateral, anterior and posterior margins of pronotum; (16) idem, detail of left anterior trichobothrial area; (17) idem, detail of right posterior trichobothrial area; (18) idem, left posterior comb of pronotum; (19) lateral margin of mesonotum; (20) idem, trichobothrial areas of right side; (21) idem, left posterior comb of mesonotum; (22) lateral margin of metanotum; (23) idem, trichobothrial areas of left side. Scale bars = 0.1 mm.

Figures 24–31. Heterolepisma coorongooba sp. nov.holotype ♀ (24) presternum, prothoracic sternum and PI; (25) mesothoracic sternum; (26) metathoracic sternum and PIII; (27) urotergite III; (28) idem, sublateral comb; (29) idem, submedial comb; (30) urotergite IX, infralateral combs; (31) urotergite X. Scale bars = 0.1 mm.

Figures 32–36. Heterolepisma coorongooba sp. nov. holotype ♀, unless otherwise indicated by specimen number (32) urosternite III; (33) idem, posterior comb; (34) coxites VIII and IX, ovipositor and styli; (35) coxite IX, paramere and penis (K.260993); (36) paramere (K.260993). Scale bars = 0.1 mm.