Amychus candezei Pascoe, 2010

Marris, John W. M. & Johnson, Paul J., 2010, A revision of the New Zealand click beetle genus Amychus Pascoe 1876 (Coleoptera: Elateridae: Denticollinae): with a description of a new species from the Three Kings Islands, Zootaxa 2331 (2331), pp. 35-56 : 40-47

Amychus candezei Pascoe

( Figs. 1, 4, 7, 12–19)

Amychus candezei Pascoe 1876: 49 ; Pascoe 1877: 416; Hudson 1934: 81.

Amychus schauinslandi Schwarz 1901: 194 ; Emberson 1998: 38

Amychus rotundicollis Schwarz 1901: 196 ; Emberson 1998: 38

Psorochroa schauinslandi (Schwarz) ; Schwarz 1907: 232, Pl. 6, fig. 2.

Psorochroa rotundicollis (Schwarz) ; Schwarz 1907: 232.

Adult material examined. Amychus candezei . Lectotype: here designated. “ Syntype [Round, bluebordered label] / type / Chatham I [Oval label, in Pascoe’s handwriting] / Amychus candezei Type, Pasc. [In Pascoe’s handwriting] / Pascoe Coll. 93-60 / Pascoe 93-60 refers to Acccession to coll [ BMNH collection] of Coleoptera 1870 –1909. [Label added by C. von Hayek] / LECTOTYPE Amychus candezei Pascoe 1876 Marris & Johnson 2010 ” [Specimen length 17.5 mm] ( BMNH). Paralectotypes: “ Syntype? [Round, bluebordered label] / ♀ / Chatham Is. [In Pascoe’s handwriting] / Janson coll. 1903-130 / Amychus candezei, Pasc. A.M.N.H. Ser. 4. XVII. p. 49 (No. 97. Jany. 1876). [The determination label is almost certainly that of Janson (C. von Hayek pers. comm. 2003)] / PARALECTOTYPE Amychus candezei Pascoe 1876 Marris & Johnson 2010 ” [Specimen length 17.5 mm] ( BMNH); “ Amychus candezei, Pascoe Type mihi D.S. [D. Sharp] Chatham Isld [Text written on specimen card mount] / New Zealand / Sharp Coll. 1905-313. / Syntype? [Round, bluebordered label] / PARALECTOTYPE Amychus candezei Pascoe 1876 Marris & Johnson 2010 ” [Specimen length 15.0 mm] ( BMNH).

Amychus schauinslandi . Syntype ♂ “Chat-ham [Small label, written ‘Chat-‘ on first line ‘ham’ on second] / Typus [Printed red label] / Amychus Schauinslandi Schw. ” [Specimen covered in fungal hyphae and is missing all except the first two segments of the left antenna, length 17 mm] ( UMBB) .

Additional material examined. Adults. New Zealand, Chatham Islands: Chatham Island : Hapupu (6 sex unknown; NZAC) , Kaingaroa (1 ♂, CMNZ) ; Forty Fours (6 ♂, 4 ♀, 17 sex unknown; CMNZ, LUNZ) ; Little Mangere Island (1 ♀; LUNZ) ; Mangere Island (2 sex unknown; LUNZ) ; Pitt Island (1 ♀, 6 sex unknown; BMNH, CMNZ) ; South East Island (8 ♂, 8 ♀, 26 sex unknown; LUNZ, NZAC) ; Star Keys (2 ♂, 2 ♀, 11 sex unknown; LUNZ) ; The Sisters (4 ♂, 3 ♀, 4 sex unknown; CMNZ, NZAC) . Locality unrecorded: (2 sex unknown; BMNH, NZAC) . Pupa . New Zealand, Chatham Islands : New Zealand, CH, Star Keys , 23.i.1998, J.W.M. Marris, in soil under tussock base by rock face (1, LUNZ) . Larvae . New Zealand, Chatham Islands : New Zealand, CH, Star Keys , 23.i.1998, J.W.M. Marris, in soil under tussock base by rock face (4, LUNZ) ; same data, died 20.iii.1998 (1, LUNZ) ; same data, died 28.x.1998 during lab rearing (1 + exuvium, LUNZ) ; New Zealand, CH, South East I., Woolshed Bush , 22.i.1998, J.W.M. Marris, ex rotten Plagianthus branch on ground, died during rearing (1 + exuvium, LUNZ) ; Mangere I., Chatham Is. , 18.ix.1970, J.I. Townsend, litter 701178 (1, NZAC) ; Chatham Is. , Mid Sisters I., 24.ix.1973, A. Whittaker, fern 73/152 (3, NZAC) ; New Zealand, CH, South East I., 17.i.1997, J.W.M. Marris, ex Myrsine log (1, LUNZ) ; New Zealand, CH, Chatham Islands, Little Mangere I., 23-6.i.1998, M & D. Bell, I Atkinson (1, LUNZ) .

Adult Diagnosis. Known only from the Chatham Islands. Distinguished from other Amychus species by the following combination of characters: integument of dorsum with numerous weakly raised glossy pustules; prothorax with sides moderately curved to near apex of hind angles; elytra with disc convex at midlength, lacking strongly developed tubercles; hind wings micropterous.

Adult Redescription. As for the genus description and as follows. Form. Body ( Fig. 1) length (excluding head) 12.7–18.5 (x =15.7) mm, width 4.6–7.4 (x = 6.0) mm (n =25 for all measurements given for this species unless stated otherwise), moderately convex. Integument of dorsum with numerous weakly raised glossy pustules. Vestiture of dorsum moderately stout, golden.

Head. Head ( Fig. 1) with pustules on frontal region; EI 0.19–0.24 (0.22).

Thorax. Prothorax ( Fig. 1) broad, PI 71–80 (75), not explanate, sides moderately curved to near apex of hind angles, widest at about posterior 2/3 rd, hind angles parallel-sided to weakly convergent; disc moderately convex with faint median longitudinal depression. Hypomeron punctate throughout. Prosternum with anterior chin piece separated from basal section by a more or less distinct transverse sulcus; chin piece weakly to moderately deflexed ventrally. Prosternal spine length 1.0–1.4 (x =1.2) (n =19) x procoxal cavity width. Scutellum with sides straight anteriorly. Elytra length 9.2–13.4 (x =11.3) mm; sides curved to apex, apex narrowly rounded; disc convex; surface with faint humeral and lateral tubercles; punctate, punctures widely separated; intervals convex, intervals 1, 3, 5, 7,and 9 raised; integument with numerous weakly raised glossy pustules. Hind wings micropterous; length 4.7–5.9 (x =5.1) mm (n =6), width 0.9–1.5 (x =1.2) mm (n =6); venation as in Fig. 5.

Abdomen. Abdominal ventrites evenly punctate throughout.

Male genitalia. Aedeagus ( Fig. 7) length 2.0–2.3 (x =2.2) mm (n =16), width 0.6–0.7 (x =0.6) mm (n =16), 3.2–3.7 x as long as wide.

Female genitalia. Ovipositor length 4.6–5.2 (x =4.7) mm (n =5); coxite length 1.1–1.2 (x =1.1) mm (n =5); styli length 1.1 mm (n =6). Genital tract as given for generic description.

Pupa Description. ( Figs. 12–15) Pupa (Figs. 12,13) exarate; length 23.5 mm, width 7.0 mm; pale yellow thoughout, except brown to black mandible apices, compound eyes, and pretarsal claws. Head hypognathous, partially retracted into prothorax; antenna ( Fig. 14) lying straight and across hypomeron toward hind angle of pronotum. Pronotum shallowly convex; anterior angles each with single attenuate tubercle, hind angles each with single attenuate tubercle coincident with position of large hind angle seta of imago, and a pair of attenuate tubercles anterad of the scutellar emargination. Elytron ( Fig. 14) and wing narrow, arcuate to ventrolateral area of thorax. Tarsus with extended ventral lobes coincident with setal pads of imago on tarsomeres 1–4; claws with 2 digitiform ventral lobes coincident in position with large ventral setal group in imago. Abdomen with hind angles of tergites slightly elevated, but lacking gin-traps; anal region ( Fig. 15) with a pair of arcuate and attenuate tubercles each side.

Larva Description. See Figs. 16–19, and as for the genus description and as follows: Length ca. 27.0 mm (probably 3rd instar); head with frons narrowly pedunculate posteriorly, posterior frontal arms of sutures shallowly and evenly arcuate; abdomen with terga 1–8 with fine punctures, on terga 1–7 each puncture adjacent to a short, transverse, moderately sclerotized carinula that partially forms the puncture margin; punctures extending to posterior margin of tergite, but carinulae becoming obsolescent at posterior third on terga 7–8; tergite 9 with dorsolateral tubercles with anterior pair elevated, distinct, apex arcuate posteromedially.

Notes. Elaterid larvae typically develop through 3–5 instars ( Johnson 2002), with the lower number being the most commonly observed value. We have inadequate material of Amychus larvae to accurately assess instar numbers, but presume the standard three-instar pattern and estimate the instar for specimens by using body proportions relative to pupal and adult size. The two larvae and one pupa reported here from Star Keys were collected together. As such, the larger larva is judged a mature and probable 3rd instar specimen. The second larva measured ca. 16.5 mm in length and may represent a mature 2nd instar larva. A third specimen measured 16.7 mm in length, is unnaturally contracted, but is probably also a 2nd instar. One specimen measured ca. 33.5 mm and another ca. 40.3 mm, but these are highly distended specimens yet are probably 3rd instar larvae.

Distribution. Restricted to the Chatham Islands group ( CH) from: Chatham Island (43°55’S, 176°30’W), Little Mangere Island (Tapuaenuku) (44°17’S, 176°19’W), Mangere Island (44°16’S, 176°18’W), Pitt Island (44°17’S, 176°13’W), South East Island (Rangatira) (44°21’S, 176°10’W), Star Keys (Motuhope) (44° 14’ S, 176° 49’ W), The Forty Fours (Motuhara) (43°58’S, 175°50’W), and The Sisters (Rangitatahi) (43°34’S, 176°49’W).

Amychus candezei is largely confined to islands free of introduced mammalian predators within the Chatham Islands group except for Chatham Island , where mice ( Mus musculus Linnaeus ), Norway rats ( Rattus norvegicus Berkenhout ) and ship rats ( R. rattus Linnaeus) are present. Emberson (1998) noted that this species was last found on Chatham Island at Hapupu in 1967 but could not be found there in 1992. Subsequently, however, one beetle was found under a log at this locality in 2001 (J.I. Townsend pers. comm. 2003) and another was collected from under loose bark in 2005 (J. Goldberg pers. comm. 2009). Specimens have also been collected recently in the north-western part of Chatham Island from the Harold Peirce Scenic Reserve (43°46’S, 176°48’W) (D. Clarke pers. comm. 2006) and nearby at Waitangi West (43°47’S, 176°49’W) (N. Curtis pers. comm. 2008) .

Biology. Adults have been collected on tree trunks (including Melicytus chathamicus (F. Meull.) Garnock-Jones and Olearia traversii (F. Meull.) Hook. f.) at night, under logs, and from under rocks and low vegetation in coastal scrub and sward. Larvae have been collected from rotten Plagianthus and Myrsine wood, in soil at the bases of tussock grasses and from fern litter.

Remarks. A lectotype for Amychus candezei Pascoe is hereby designated to ensure nomenclatural stability by clarifying the nominal taxon. The lectotype is considered to be the most likely specimen to have been examined by the author at the time of description based on the locality and type labels being written in Pascoe’s handwriting and the specimen having been held in his personal collection. The lectotype specimen is labelled “Chatham I”, yet Pascoe’s (1876) description noted the habitat as “Pitt’s [sic] Island ”. Earlier in the same paper, however, in the description of Inophloeus transversii the "Hab." is given as “Chatham Islands” but, in the comment which follows, Pascoe remarks "It is from Pitt's Island one of the Chatham Group where it was found by Mr Travers". The size range given by Pascoe (1876) indicates a series of specimens were examined for his description. The Janson and Sharp collection specimens are included as paralectotypes based on the knowledge that specimens were frequently given to friends (C. Von Hayek pers. comm. 2003) and, in the case of the Janson specimen, due to the locality label being written in Pascoe’s handwriting.

Hudson’s (1934) synonymy of Amychus candezei and Psorochroa granulata is incorrect as he refers to the species as being “Apparently confined to the islands in Cook Strait (Stephen’s [sic] Island and The Brothers) …”, thus indicating he was unaware of specimens from the Chatham Islands. In addition, comparison of type material clearly shows them to be separate species. Brookes (1932) was aware of a Chatham Islands species, noting that Psorochroa granulata is found on “ … Stephen [sic] Island … but is to be met with again at the Chatham Islands”, but despite this, wrongly followed Hudson’s (1934) synonymy.

Examination of the type specimen of A. schauinslandi showed no clear morphological differences from A. candezei . The type of A. rotundicollis could not be located in the Übersee Museum collection and is presumed to have been lost during World War II (P.-R. Becker pers. comm. February 1998). Emberson’s (1998) synonymy of A. rotundicollis and A. candezei is supported here based on Schwarz’s (1901) description. Moreover, the Chatham Islands’ beetle fauna has been extensively studied in recent times and is well documented ( Emberson 1998, 2002) and no specimens resembling A. rotundicollis and differing from A. candezei have been found.

Amychus candezei is listed by Molloy and Davis (1994) in Category C (the third highest priority category for conservation) and is protected under the Seventh Schedule of the Wildlife Act 1953 ( Anonymous, 1980). Hitchmough et al. (2007) placed A. candezei in the Range Restricted category of the New Zealand Threat Classification System.

Amychus granulatus (Broun)

( Figs. 2, 5, 9)

Psorochroa granulata Broun 1883: 302 – Broun 1886: 773; Hudson 1934: 81.

Amychus stephensiensis Schwarz 1901: 193 – Schwarz 1907: 232; Tarnawski 2001: 305.

Amychus granulatus (Broun) – Ramsay and Gardner 1977: 3.

Type material. Lectotype, here designated: “ Syntype [Round, blue-bordered label, added in March 2003 (C. von Hayek pers. comm. 2003)] / New Zealand Broun Coll. Brit. Mus . 1922-482 / Brothers Isles / Psorochroa graniger [sic] [In Broun’s handwriting] / 1370 [In Broun’s handwriting] / LECTOTYPE Amychus granulatus ( Broun 1883) Marris & Johnson 2010 ” [Specimen length 19.5 mm] (Broun Collection, BMNH) . Paralectotypes: “ Syntype? [Round, blue-bordered label] / Brothers Is. Cook Strait Sandager / G.C. Champion Coll. B.M. 1927-409. / Possible syntype C.M.F. von Hayek 03.2003 / PARALECTOTYPE Amychus granulatus ( Broun 1883) Marris & Johnson 2010 ” [♂, aedeagus on card, length c. 18 mm] ( BMNH) ; “ Syntype? [Round, blue-bordered label] / ♀ / New Zealand [Oval label] / 1370 [In Broun’s handwriting] / Pascoe Coll. 93-60. / Syntype? Psorochroa granulatus Pascoe, C.M.F. von Hayek 2004 . / PARALECTOTYPE Amychus granulatus ( Broun 1883) Marris & Johnson 2010 ” [ Specimen length 18.0 mm] ( BMNH) ; “The “Brothers” Cook Straits [sic] [In Broun’s handwriting] / Psorochroa granulata [In Broun’s handwriting] / PARALECTOTYPE Amychus granulatus ( Broun 1883) Marris & Johnson 2010 ” [Specimen length 19.0 mm] ( NZAC) .

Additional adult material. New Zealand, Marlborough Sounds / Cook Strait: Maud Island (1 ♂, 4 ♀, 6 sex unknown; CMNZ, LUNZ, NZAC) ; Sentinel Rock (1 ♂, 2 sex unknown; LUNZ, CMNZ) ; Stephens Island (16 ♂, 11 ♀, 53 sex unkown; BMNH, CMNZ, CNCI, LUNZ, USNM, NZAC) ; The Brothers (4 ♂, 1 ♀, 6 sex unknown; BMNH, LUNZ, MONZ, NZAC) ; Trio Islands: middle Trio Island (1 ♀, 5 sex unkown; CMNZ, LUNZ, NZAC) , south Trio Island (1 sex unknown; LUNZ) ; North Canterbury; near Waikari (1 sex unknown, CMNZ) . One specimen, collected by Helms and from the Sharp collection ( BMNH) , is labelled as from Greymouth. This was possibly mislabeled since no other records of A. granulatus are known from the Greymouth area. Helms sent beetles to Sharp from the vicinity of Greymouth and Picton ( Watt 1977). One specimen ostensibly from Ovalau , Fiji ( USNM) , is assumed to be incorrectly labelled as no Amychus species are known from beyond New Zealand.

Larval material examined. New Zealand, Marlborough Sounds / Cook Strait: New Zealand, SD, Middle Trio Island , 15.ii.1995, J.W.M. Marris, ex partially rotten base of Olearia paniculata tree (1, LUNZ)

Adult diagnosis. Extant populations known only from the Marlborough Sounds/Cook Strait region. Distinguished from other Amychus species by the following combination of characters: integument of dorsum with numerous strongly raised glossy pustules; prothorax strongly explanate; elytra strongly tuberculate, flattened mesally to steeply declivous laterally at midlength; hind wings micropterous.

Adult redescription. Form. Body ( Fig 2) length (excluding head) 16.0–22.5 (x =20.0) mm, width 6.1– 9.0 (x =7.5) mm (n =20 for all measurements given for this species unless stated otherwise), strongly flattened. Integument of dorsum with numerous strongly raised, dome-like glossy pustules. Vestiture of dorsum stout, strongly decumbent, orange.

Head. Head ( Fig. 2) with distinct pustules on frontal region; vestiture stout; EI 0.20–0.29 (x =0.24).

Thorax. Prothorax ( Fig. 2) very broad, PI 67–73 (x =70), strongly explanate; sides strongly curved to base of hind angles, widest at about midpoint, hind angles parallel-sided to weakly divergent; disc flattened. Hypomeron evenly punctate throughout. Prosternum with anterior chin piece separated from basal section by a faint transverse sulcus or sulcus obsolete; chin piece weakly deflexed ventrally. Prosternal spine length 1.3– 1.6 (x =1.4) (n =18) x procoxal cavity width. Scutellum with sides parallel-sided to weakly concave anteriorly. Elytra length 11.6–18.2 (x =14.5) mm; sides parallel-sided to basal 3/5 th, apex narrowly rounded; disc strongly flattened mesally, lateral 1/5 th steeply declivous to sides from behind humerus to basal 3/5 th; surface strongly tuberculate, tubercles prominent humerally and laterally; striae weakly impressed to obscured laterally; intervals flattened; weakly punctate, punctures widely separated; integument with numerous strongly raised glossy dome-like pustules. Hind wings micropterous; length 4.8–7.5 (x =6.0) mm (n =6), depth 1.3–1.8 (x =1.6) mm (n =6); venation as in Fig. 4.

Abdomen. Abdominal ventrites evenly punctate throughout.

Male genitalia. Aedeagus ( Fig. 9) length 2.5–3.0 (x =2.8) mm (n =10), width 0.6–0.7 (x =0.7) mm (n =10), 3.9–4.6 x as long as wide.

Female genitalia. Ovipositor length 4.3–4.7 (x =4.6) mm (n =4); coxite length 1.1–1.2 (x =1.2) mm (n =4); styli length 1.8 mm (n =4). Genital tract as given for generic description.

Larval description. As for the genus description and as follows. Length ca. 27.5 mm (early last instar); head with frons moderately pedunculate posteriorly, posterior frontal arms of sutures moderately arcuate then subparallel on vertex; abdomen with terga 1–8 with deep and moderately coarse punctures, on terga 1–7 each puncture adjacent to a transversely undulating, moderately sclerotized carinula that partially forms the puncture margin; punctures extending to before posterior margin of tergite, but carinulae becoming obsolescent at posterior third on terga 7–8; tergite 9 with dorsolateral tubercles with anterior pair low, indistinct.

Distribution. Presently restricted to islands of the Marlborough Sounds and Cook Strait (SD) from: Maud Island (Te Hoiere) (41°02’S, 173°53’E), Sentinel Rock (40°53’S, 174°08’E), Stephens Island (Takapourewa) (40°40’S, 173°58’ E), The Brothers (41°06’S, 174°26’E), and the Trio Islands (Kuru Pongi) (middle and south Trio Islands) (40°50’S, 174°00’E). Also recorded from subfossil remains from Arden near Waikari (NC) (42°57’S, 172°46’ E), South Island ( Worthy and Holdaway 1996).

Records of specimens collected from "The Brothers", were almost certainly taken from the northern island of The Brothers group (usually referred to as North Brother or Little Brother Island), which is the site of a previously manned lighthouse station. Amychus granulatus was described from specimens collected by Mr P. Stewart-Sandager ( Broun 1883) who was a lighthouse keeper on North Brother Island ( Watt 1977). There are no records of A. granulatus from South (or Big) Brother Island. Recent attempts to locate A. granulatus specimens on North Brother Island were unsuccessful and it is possible that the species is now extinct on its type locality island (Marris unpublished data).

Meads (1976) reported A. granulatus as present on Outer Chetwode Island (Te Kakaho). This record was based on the sighting of beetle remains that were not collected (M.J. Meads pers. comm. 1994). No other record of Amychus granulatus exists from Outer Chetwode Island despite recent efforts to search for this species (Marris unpublished data).

Biology. Adults have been collected from on tree trunks (including Beilschmiedia tawa (Cunn.) Benth. and Hook. f. ex Kirk, Coprosma repens Hook. f., Fuchsia excorticata (J.R. Forster and G. Forster) L. f., and Myoporum laetum G. Forster ) at night, from under logs, rocks, low vegetation ( Tetragonia tetragonioides (Pall.) Kuntze and C. repens ) and dead rank grass, and from pitfall traps. Only one larva is known for the species. This was collected from the partially rotten base of the tree Olearia paniculata (J.R. Forster and G. Forster) Druce.

Remarks. A lectotype for Amychus granulatus ( Broun 1883) is hereby designated to ensure nomenclatural stability by clarifying the nominal taxon. The lectotype is considered to be the most likely specimen to have been examined by the author at the time of description based on its identification and species number labels being written in Broun’s handwriting and its locality designation.

Schwarz (1907) transferred A. stephensiensis to Psorochroa and included it as a “var.” (= variety) of P. granulata . This ranking was repeated by Schenkling (1927). Article 45.6.4 of the Code of Zoological Nomenclature ( International Commission on Zoological Nomenclature 1999) states that the use of variety in this instance places A. stephensiensis at subspecies rank. Schwarz (1907) thereby effectively synonymised these species. Van Zwaluwenburg (1932) listed P. granulata , but did not include the synonymy while incorrectly recording the distribution as Chatham [Islands]. Tarnawski (2001) apparently overlooked both the Schwarz (1907) action and Hudson’s (1934) synonymy of the two genera. The type of A. stephensiensis could not be located in the Übersee Museum collection and it is presumed to have been lost during World War II (P.- R. Becker pers. comm. February 1998). Schwarz’s (1907) synonymy is justified based on comparison of the descriptions of the two species and because only A. granulatus has subsequently been found on Stephens Island, the type locality of A. stephensiensis .

The combination “ Amychus granulatus ” was apparently first used by Ramsay and Gardner (1977). This combination was subsequently adopted by various authors (e.g., Anonymous 1980, Meads 1990, Ramsay et al.1988).

Worthy and Holdaway’s (1996) subfossil record of A. granulatus (see Distribution) is the only record of this species, or any Amychus species , from mainland New Zealand. They collected a partly damaged pronotum (not a single elytron as noted) from a nest site of the extinct laughing owl ( Sceloglaux albifacies Gray ). The specimen was identified as “ Amychus cf. granulatus ”, however, the shape and dimensions of the pronotum are consistent with A. granulatus . Kuschel and Worthy (1996) identified several large flightless weevil ( Coleoptera : Curculionidae ) species, which are presently restricted to rodent-free offshore islands, from subfossil nest and cave deposits from mainland New Zealand. They attributed the reduction in range of these species as primarily due to predation by introduced rodents. The mainland subfossil record of A. granulatus and the species’ present distribution on rodent-free islands supports this hypothesis.

Amychus granulatus is listed in Molloy and Davis (1994) in Category B (the second highest priority category for conservation) and is protected under the Seventh Schedule of the Wildlife Act 1953 ( Anonymous 1980). Hitchmough et al. (2007) placed A. granulatus in the Nationally Endangered category of the New Zealand Threat Classification System.