Maritisma coralinium, 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 : 171-176

Maritisma coralinium sp. nov.

http://zoobank.org/NomenclaturalActs/ CC4C0649-D95F-42E5-8DE1-18BAA041F6A4

Figs 169–207

Holotype ♂ ( HW 1.14 ) ( AM K.261124 K.261125 on two slides) CORAL SEA TERRITORY: Herald Cay (unspecified), Great Barrier Reef, 17.0°S 149.2°E, 7 September 1967 . Paratype. juvenile ♀ ( HW 0.84) (K.261252 K.261253 on two slides) CORAL SEA TERRITORY: North East Herald , 22.vi.1997, A. Anderson .

Diagnosis. This species can easily be distinguished from H. dispar in having one fewer pair of styli in the female and 2+2 combs on urotergite VIII (apparently 3+3 combs in H. dispar which would be very unusual), the shape of the thoracic sternites (apparently somewhat pointed in H. dispar ), the much shorter penultimate article of the maxillary palp relative to the ultimate article (subequal in H. dispar ).

Description

Appearance: Medium sized silverfish, thorax not wider than abdomen ( Fig. 169 ) which only tapers slightly posteriorly from about the fourth abdominal segment; appearance when live unknown.

Body length: H+B 5.7 mm; HW 1.14 mm; thorax: length 1.8 mm or 0.32 H+B; width up to 1.5 mm with no great difference between the pro, meso- and metanota although the metanotum is the widest and the pronotum the narrowest, pronotum slightly longer than meso- or mesonota; antennae not complete 4.0 mm or>0.70 H+B; terminal filaments almost completely lost.

Pigmentation: Without pigment, possibly because of long time in alcohol. Paratype (K. 261252) has some reddishbrown pigment around the eyes but otherwise appears to be without pigment.

Macrochaetae: Smooth, hyaline, apically bifurcate with truncated tips to each bifurcation ( Fig. 170 ). Some macrochaetae on tibia, stout carrot-shaped. Some macrochaetae on tibia and tarsi appear slightly twisted, which is considered an artefact of the mounting medium as (e.g., Smith et al., 2012).

Scales: Quite broad, hyaline, with unusually widely spaced subparallel ribs that do not surpass the margin of the scale ( Fig. 171 ). Scales found on top of head, absent from clypeus and labrum as well as all cephalic appendages; present on all nota, all thoracic sterna, and the coxae but absent from remaining leg articles, present on all urotergites and urosternites, absent from styli and terminal filaments. Lanceolate and triangular scales not seen.

Head: Wider than long ( Fig. 172 ), without distinct bushes. Frons projected forwards slightly in anterior corners; anterior margin with about 3+3 macrochaetae (lacking distinct medial gap) which join laterally with the rows of macrochaetae along the margin, running back to the eyes, with just a couple of macrochaetae above the eyes; peri-antennal groups illdefined, of two macrochaetae located more mesad than the margin macrochaetae. Clypeus with longer macrochaetae laterally and across the face proximally, with small setae medially. Labrum ( Fig. 172 ) with many macrochaetae distributed across the proximal half and some smaller setae in the anterior half. — Scape and pedicel of antennae ( Fig. 173 ) both comparatively short, each with a subapical rosette of small macrochaetae and setae. First annulus of flagellum with very few setae; subsequent annuli with a rosette of small setae and some very short trichobothria, the divisions between the annuli difficult to discern in the slide mounted material. Most distal surviving intervals (probably about mid-antenna) ( Fig. 174 ) divided into repeated patterns of four annuli, each with two rosettes of fine setae, rod-like basiconic sensilla may or may not be present (a vague impression of a basiconic sensilla was seen in the distal annulus of two intervals but were not seen with any confidence). — Mandibles short and robust ( Figs 175, 176 ) but otherwise of a form typical for the Heterolepismatinae with well-developed molar and incisor areas; a group of about nine strong and short or thin and longer, apically bifurcated setae distally adjacent to the molar region and a bush of about 20 macrochaetae externally. — Maxilla ( Figs 177, 178 ) with several 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 five to seven setae, galea with one stronger seta proximally but otherwise with only short fine cilia or setulae; apical article of maxillary palp ( Fig. 179 ) 4.6 times longer than wide (range 4.3–5.0) and 1.9 times longer than the penultimate article (range 1.4–2.3), the ultimate article without branched papillae but with a single sausage-shaped basiconic sensillum type C near the apex (although on the juvenile paratype K.377828 this sensillum looks more like a basiconic sensillum type B), last three articles of palp with fine setae only, two basal articles with subapical rosettes of slightly thicker setae. — Labium ( Fig. 180 ) wider than long, postmentum with setae scattered irregularly across the anterior third, prementum with transverse and oblique groups of strong setae and with short setulae distally; apical article of labial palp, much wider than long (L/ W 0.61), especially medially, with five papillae of the aufgelöst type arranged in a three plus two arrangement, the distal three being much larger than the other two, no other sensilla seen; covered with numerous fine short setae, those proximal and medial longer than those distal and/or lateral; penultimate article with three stronger setae medially.

Thorax: Pronotum ( Fig. 181 ) with weak setal collar of short macrochaetae and some small setulae and cilia, chaetotaxy largely absent in medial region; setae of lateral margins lost, but consisting of marginal setae as well as setulae and two submarginal macrochaetae, one about one quarter the distance along the margin and the other about three quarters along the margin associated with the posterior trichobothrial area; on the left side there are two submarginal macrochaetae, the more mediad being smaller. Anterior trichobothrium about half way along the margin mediad of a marginal macrochaeta but otherwise without any special chaetotaxy ( Fig. 182 ). The posterior trichobothrium mediad of a submarginal and a marginal macrochaeta with some two or three setulae posterior to this group ( Fig. 183 ). Posterior margin with 1+1 single macrochaetae (absent on left side in holotype) each associated with two cilia ( Fig. 184 ). — Mesonotum ( Fig. 185 ) with similar lateral chaetotaxy to pronotum except two of the submarginal macrochaetae form combs of two at least on the right side (left side damaged); both trichobothrial areas are more posterior ( Fig. 186 ) than on the pronotum, the anterior about ⅔ along the margin, not associated with any macrochaetae; 1+1 posterior macrochaetae as in pronotum. — Metanotum ( Fig. 187 ) similar to mesonotum except the trichobothrial areas even more posterior ( Fig. 188 ).

Presternum narrow, with transverse row of strong macrochaetae ( Fig. 189 ). All thoracic sterna with hyaline scales. — Prothoracic sternum ( Fig. 189 ) subparabolic, about as wide at base as long (L/ W 1.03), posterior two thirds of lateral margins with submarginal macrochaetae, often grouped into pairs. — Mesosternum ( Fig. 190 ) sub-parabolic (L/ W 1.13) with about 12 macrochaetae submarginally along the posterior third of the margin. — Metasternum ( Fig. 193 ) apically rounded, about 1.25 times wider than long (L/ W 0.81), distal third of lateral margins with submarginal rows of macrochaetae as well as some marginal setae and cilia, the small gap between the combs relative to the average length of each comb 0.62.

Legs ( Figs 189, 191, 192 , 194 ) becoming progressively longer and more slender with the tibia PI / PIII of 0.58 and the tarsi of PI / PIII of 0.69; tibia L/W ratio of legs of holotype PI 2.6 , PII 3.1 , PIII 4.2 ; tarsi L/W ratio PI 7.7 , PII 8.9 , PIII 11.8 . Coxa of PI with comb of three strong macrochaetae near the anterolateral corners followed by many strong macrochaetae along the external margin, becoming more numerous distally; inner margin with three macrochaetae distally over the articulation and another seta subdistally near a long thin seta on the dorsal face. Trochanter with several setae. Femur ventrally with some macrochaetae along the posterior margin and another subdistally on the midline of the ventral face, distal anterior corner with one (?) macrochaeta, otherwise no obvious chaetotaxy along the ventral face of the distal end, ventral surface of femur with long setae. Tibia with a strong carrot-shaped macrochaeta distally as well as a few smaller strong setae, ventral margin with two short macrochaetae near the middle and another near the proximal end, dorsal or outer margin with one short pointed macrochaeta about one quarter the distance along the margin and another three quarters along; apical spur distinctly hooked ( Fig. 191 ) and bearing two small setae; face of tibia also with setae. Tarsi of four articles, the basal tarsal article of PI longer than remaining articles together, bearing some stronger setae below; second article particularly short with two long setae, suture between third and fourth articles weak. Pretarsus with two long curved lateral claws and a much shorter straight medial claw. PII and PIII similar to PI except lacking the anterolateral comb on the coxae and with fewer macrochaetae in the posterolateral region; the relative length of the basal tarsal article is progressively longer, being about 63% of the total length on PIII. Tibia of both PII and PIII with more numerous stout macrochaetae along much of the length of the posterior margin

Abdomen: Urotergites I–VII with 3+3 small combs ( Fig. 195 ), number of macrochaetae per comb as shown in Table 9, each lateral comb associated with two to three cilia near the insertions and zero to four setulae nearer the margins, each sublateral comb associated with one to four cilia and zero to two setulae, each submedial comb of only one macrochaeta with a cilium on each side ( Figs 196–198 ); urotergite VIII with 2+2 combs, lacking the sublateral comb; urotergite IX without combs but with three setulae in each infralateral corner ( Fig. 199 ). Urotergite X (possibly slightly damaged in holotype) ( Fig. 200 ) does not project posteriorly (L/W about 0.2) but is very similar to that of the juvenile female paratype (L/ W 0.23, range 0.19–0.26); four or five macrochaetae on each side as well as some setulae ( Fig. 201 ).

Urosternite I ( Figs 202, 203 ) with comb of eight macrochaetae and one setula medially on slightly protruding region, urosternite II with 1+1 lateral combs each of eight macrochaetae (right comb missing on deformed part of posterior margin in holotype) and two marginal setulae, urosternites III–VIII (juvenile ♀ with combs of 2–3 macrochaetae on coxites VIII) with 1+1 lateral combs of four to twelve macrochaetae associated with a cilium at the laterad end and two to five setulae mostly located on the margin or between the comb and the margin but occasionally between the insertion points of the macrochaetae ( Figs 204, 205 ). The distance between the lateral combs 1.5–2.1 times the width of these combs. The spacing between the macrochaetae of the combs is always quite wide.

Each coxite IX of ♂ short ( Fig. 206 ), the internal process acute apically, a little wider at its base than long (L/ W 0.8) and about 2.2–3.1 times longer than the external process; external and internal margins of internal process and external margin of outer process with some setae, with a few near the apex of the inner process fairly strong. Penis typical with numerous glandular setae apically, each set on a protuberance. Parameres almost as large as the inner processes with about 40 thin setae.

Only one pair of styli ( Fig. 206 ) present (IX); each stylus with line of stronger setae along the length of the ventral margin. Styli IX in male holotype (excluding the apical macrochaetae) about two and a half times the length of the internal process.

Cerci in holotype largely damaged with the two remaining basal divisions lacking scales. In juvenile female paratype, the divisions are shorter than wide until the fifth division, the sixth division is divided into two annuli with larger macrochaetae only in the distal annulus, the seventh division is divided into three annuli, the eighth into four with trichobothria subdistally in the second and larger macrochaetae subdistally in the ultimate annuli (missing beyond here). The median dorsal appendage is similarly organised with shorter divisions basally and the fourth about as long as wide, the fifth and sixth are divided into two annuli and the seventh and eighth into four and the ninth into at least six annuli (broken beyond here).

Female: Known only from juvenile specimen ( Fig. 207 ).

Habitat. Collected on a remote coral cay, over 300 km from the mainland of Australia, where many birds roost but there is no specific data on collection site on the label of the holotype .

Paratype collected in rotten wood and leaf litter of Pisonia [ Nyctaginaceae ].

Etymology. Named from the Latin noun for coral.

Figures

Figures 169–180. Maritisma coralinium gen. nov., sp. nov. holotype ♂ K.261124 K.261125 (169) habitus (terminal filaments lost); (170) smooth, apically bifurcate seta of setal collar; (171) scale from pronotum; (172) head, frons drawn separate from rest as it was folded back under the clypeus in the mounted material; (173) antenna, scape, pedicel and basal intervals of flagellum; (174) idem, most distal surviving interval showing possible basiconic sensillum (bsB?); (175) mandible; (176) idem, incisor and molar regions; (177) maxilla; (178) idem, lacinia and galea; (179) idem, apex of ultimate article of palp showing basiconic sensillum type C (bs); (180) labium. Scale bars = 0.1 mm unless otherwise indicated.

Figures 181–192. Maritisma coralinium gen. nov., sp. nov. holotype ♂ K.261124 K.261125 (181) pronotum; (182) idem, right anterior trichobothrial area; (183) idem, right posterior trichobothrial area; (184) idem, left posterior comb; (185) mesonotum, right side; (186) idem, trichobothrial areas, right side; (187) metanotum, right side; (188) idem, trichobothrial areas, left side; (189) presternum, prothoracic sternum and PI; (190) mesothoracic sternum; (191 apex of tibia of PI; (192) PII. Scale bars = 0.1 mm.

Figures 193–205. Maritisma coralinium gen. nov., sp. nov. holotype ♂ K.261124 K.261125 unless otherwise noted by specimen number (193) metathoracic sternum; (194) PIII; (195) urotergite II; (196) idem, left lateral comb; (197) idem, left sublateral lateral comb; (198) idem, left submedial comb; (199) urotergite IX, left infralateral comb; (200) urotergite X; (201) urotergite X of paratype K.261253; (202) urosternite I; (203) idem, medial comb: (204) urosternite IV; (205) right comb of urosternite VI. Scale bars = 0.1 mm.

Figures 206–207. Maritisma coralinium gen. nov., sp. nov. holotype ♂ K.261124 K.261125 unless otherwise noted by specimen number (206) coxites IX, penis and parameres; (207) sternite VII, coxites VII and IX of subadult female K.261253. Scale bars = 0.1 mm.