Ceratomerus orientalis, Bradley J Sinclair, 2003

Bradley J Sinclair, 2003, Taxonomy, Phylogeny and Zoogeography of the Subfamily Ceratomerinae of Australia (Diptera: Empidoidea), Records of the Australian Museum 55, pp. 1-44 : 39-42

Ceratomerus orientalis n.sp.

Figs. 29, 87, 99, 120–124

Type material. HOLOTYPE 3, “ AUST [ralia]: NSW[New South Wales]: Royal/ N.P., Bola Creek/ 3.iv.1994 / B.J. Sinclair ”; “ HOLOTYPE / Ceratomerus / orientalis/ Sinclair [red label]” AMS K175252 .P ARATYPES: New South Wales: 1♀, same data as holotype; 533, 3♀♀, Barrington Tops NP, 350 m, lower Gloucester R., 2.xii.1988, 21.xii.1993, DJB; 13, same locality, Upper Williams R., 550 m, 26.i.1987, DJB; 433, 2♀♀, same locality, Gloucester Tops , 1280–1290 m, Nothofagus , 14.xi– 30.xii.1988, DJB; 13, Blue Mtns NP, Burralow Swamp , 9.xii.1986, G.A. Holloway; 1033, 6♀♀, Blue Mtns NP, Valley of the Waters , Vera Falls , 10.vii.1994, 23.x.1994, 9.iv.1995, BJS; 533, Carrai SF, Coachwood Ck nr Kookaburra Camp , 8–9.ii.1997, DJB; 7 33, 2♀♀, Chichester SF, Upper Allyn R., 400 m, subtrop. rainfor., 19–20.xii.1993, DJB, nr Eccleston , 4.v.1967, DKM; 3333, 8♀♀, Cockerawombeeba Ck , 23 km WNW Bellangry, warm temp. rainfor., 8.xii.1986, 14–15.i.1988, DJB; 533, 1♀, Comboyne-Wingham Rd , 10 km SSW Comboyne, rainfor., y.pans, 19.ii.1993, DJB; 13, Cooranbong , Gap Ck FlR, 3–4.ii.1986, B.J. Day, DKM; 233, 1♀, Dingo Tops For. Pk, NW Wingham, rainfor., 950 m, y.pans, 19.ii.1993, DJB; 1133, 4♀♀, “Lorien”, 3 km N Lansdowne, nr Taree , rainfor./wet scler. for., 6.i.1988, 4–10.v.1987, 16–30.viii.1992, 20–26.ix.1992, DJB, G. Williams; 2 33, Lyons Ck , 8 km NW Nelligen, riv. for., y.pans, 2.i.1991, DJB; 13, 1♀, Mooney Mooney Ck nr Gosford , 26.i.1984, B. Duckworth, B. Day, DKM, 3.xii.1985, DJB; 233, Mt. Hyland NP, Obeloe Ck , 1030 m, 30°10'S 152°27'E, warm temp. rainfor., 25–27.i.1996, DJB; 3 33, 6♀♀, Mt. Kaputar NP, nr Green Ck, 950 m, y.pans, 18.xi.1990, DJB, ck at Road, 750 m, 18.xi.1990, DJB; 13, 2♀♀, Mt. Warning NP, 24.xi.1985, DJB & G. Cassis; 333, 2♀♀, Nadgee NP, Merrika R./Nadgee R., dry scler. for., 1.ii.1987, 13–19.ii.1987, DJB; 233, 1♀, Nadgee NP, nr Eden, 14–15.ii.1986, DJB; 7 33, 1♀, Royal NP, Wallumarra Tr., Bola Ck, subtrop. rainfor., y.pans, 7.xi.1993, BJS; 1♀, Royal NP, E. Waterfall, rainfor., 8.iii.1991, DJB; 433, 6♀♀, Tooloom Scrub For. Res., Legume Rd nr Urbenville, 10–11.i.1988, DJB; 533, 3♀♀, Washpool NP, Coombadjah Ck, warm temp. rainfor., 780 m, 6.xii.1992, DJB; 433, 2♀♀, Werrikimbe NP, 23.iii.1985, DJB & B. Day, Cobcroft Ck, warm temp. rainfor., 27.xii.1993, 1–5.xii.1997, DJB; 333, 3♀♀, Wilson R. Res. nr Bellangry , subtrop. for. y.pans, 5.xii.1988, DJB, 27.i.1983, DKM & K.C. Khoo; 2♀♀, National Park, 6.xii.1958, DKM; 233, Nightcap NP, Googarna Rd, NE Nimbin, 14–15.xi.1988, DJB; 433, Nightcap NP, Terania Ck, N. Lismore, 15–16.xi.1988, DJB; 233, Nightcap NP, Googarna Rd, NE Nimbin, 14–15.xi.1988, DJB; 433, Nightcap NP, Terania Ck, N. Lismore, 15–16.xi.1988, DJB ( AMS); 1833, 2♀♀, Barrington Tops NP, Williams R., subtrop. rainfor., 480 m, y.pans, 19–20.xii.1993, BJS, DJB ( AMS, CNC); 11 33, 4♀♀, Blue Mtns NP, Mt. Wilson , 19.xii.1986, DKM, B.J. Day, R. de Keyzer ( AMS), Waterfall Ck, 22.xi.1993, 12–13.xii.1998, BJS; 22 33, 4♀♀, Border Ranges NP, Brindle Ck, 800–1000 m, rainfor., y.pans, 25–26.i.1995, BJS ( CNC); 533, 4♀♀, Blue Mtns NP, Wentworth Falls , Jamison Ck, 23.x.1994, 10.xi.1993, BJS ( AMS, ZFMK); 233, Bruxner Pk FlR nr Coffs Harbour, Bucca Bucca Ck, subtrop. rainfor., 100 m, 1.iv.1995, BJS ( ZFMK); 2633, 5♀♀, Dorrigo NP, 12.x.1962, DHC ( ANIC), 22– 23.x.1980, subtrop. rainfor., DJB ( ANIC, WOOC), Rosewood Ck, y.pans, 23.i.1995, BJS ( CNC), Wonga Walk, 700 m, Crystal Shower Falls ,

2.iv.1995, BJS ( ZFMK) ; 13, 1♀, Fitzroy Falls , 23.i.1963, DHC ( ANIC) ; 2033, 8♀♀, Ku-ring-gal Chase NP, Gibberagong Tr., trib. Gully Ck, 20.xi.1993, BJS ( ZFMK) , McCarrs Ck, 28.i.1985, DJB ( AMS) , Cicada Ck nr Church Pt , 11.xi.1990, 28.xii.1992, DJB ( AMS) ; 2633, 12♀♀, 7 km E Robertson, Macquarie Pass NP, subtrop. rainfor ., 23.xi.1993, BJS ( CNC) , 30.iii.1986, 27.ii.1991, DJB ( AMS) ; 1633, 16♀♀, Minnamurra Falls , 31.i.1962, 28.v.1963, 4.x.1965, DHC ( ANIC) , 7.i.1961, 20.x.1961, DKM ( AMS) , iii.1983, B.Day, K.C. Khoo ( AMS); 3033, 27♀♀, Royal NP, Otford , 31.xii.1962, DHC ( ANIC) , 6.xii.1958, 10.ii., 3.iii.1962, DKM ( AMS) ; 15.ii.1957, W.W. Wirth ( USNM); 633, 5♀♀, Royal NP, Bola Ck, subtrop.rainfor ., 29.xii.1993, BJS ( ZFMK) , 12.ii.1985, DKM ( AMS) ; 933, Royal NP, Couranga Tr., dry scler. for., 19.iii.1995, 23.iv.1995, 29.v.1994, BJS ( CNC, ZFMK) ; 233, Royal NP, National Falls , 29.v.1994, BJS ( ZFMK) . Queensland: 833, 22♀♀, Bunya Mtns NP, Saddleback Ck, rainfor., 950 m, y.pans , 25–26.xi.1992, DJB , y.pans/ MT, 4–6.xii.1985, DJB & G. Cassis; 1 3, 2♀♀, Horse Gully Ck, base Bunya Mtns, dry scler. 500 m, y.pans, 26.xi.1992, DJB ; 1033, Mt. Spurgeon , 16°26'S 145°12'E, 1250 m, wet sclero. for. & ck, y.pans , 18–19.iv.1994, DJB ; 533, 1♀, Teviot Ra., Rd to Boonah below Wilsons Pk, 24.i.1995, BJS ( AMS) ; 533, 1♀, Mt. Windsor Tableland , 16°26'S 145°12'E, 1000 m, ck , 16.iv.1994, BJS ( ZFMK) . Victoria: 1333, 4♀♀, Burrowa-Pine Mtn NP, Bluff Ck Picnic A., 400 m, riverine for. y.pans , 29.xi.1994, DJB ; 13, Errinundra Plateau , Bonang Ck, y.pans , 1.iv.1990, DJB ( AMS) .

Additional material (in alc.). Australian Capital Territory: 233, Wombat Ck , 6 km NE Piccadilly Circus, 35°19'S 148°51'E, 750 m, iv.1984, Weir, Lawrence, Johnson ( ANIC) .

Diagnosis. Recognized by the dark-coloured pleura, distinct iridescent pruinescence on katepisternum, distinct brush of setae at base of the male mid femur, and the tri-lobed epandrial process.

Description. Wing length 2.5–3.1 mm, similar to C. attenuatus except as follows:

Male. Head. Postocellar bristles one-third length of ocellar bristles. Antenna with length of scape less than height of eye; postpedicel apical two-thirds strongly tapered; threesegmented stylus one-fourth length of postpedicel; length of segment 8 subequal to width.

Thorax. Scutum, postnotum and pleura dark brown (pleura paler in northern populations); postpronotal lobe pale brown, with pale streak extending to base of fore coxa; scutum lacking vitta of pruinescence.

Wing ( Fig. 87). Stigma faint. R 2+3 running parallel and close to costa, smoothly arched around stigma.

Legs. Fore and mid coxae yellow, hind coxa yellowishbrown; base of femora, especially inner margin yellow, becoming dark brown towards tip. Fore femur slightly swollen, with av row of fine setae, less than half width of femur.

Mid femur slightly swollen with pv row of short, dark setae along basal two-thirds; base with long erect pv seta; base with av cluster of long stout setae, nearly equal in length to width of femur; av margin with row of short, pale setae along entire length ( Fig. 99). Mid tibia slightly arched, not swollen at mid-length, with pv row of fine setae; apex with av cluster of short, erect setae; 1 erect dorsal seta near midlength and 1 erect ad setae on basal third.

Hind femur with av row of very short setae.

Abdomen dark brown, concolorous with mesonotum; intersegmental membrane between S 6–7 often with pair of lateral patches of dark, dense microtrichia; S7 one-half longer than preceding sternite, anterolateral margin produced anteriorly, articulated with S8; T8 broad, rectangular, one-third length of sternite.

Terminalia ( Figs. 120, 121). Hypandrium convex, posterior margin with flap-like extension; gonocoxal apodemes developed, slightly projected beyond anterior margin; anterior margin of hypandrium with wing-like lateral wall upon which epandrium articulates; postgonites articulated at base of phallus, erect, slightly arched with hooked tips; phallus with pair of strongly recurved, posteriorly directed sickle-shaped processes. Epandrium lacking very long, stout setae; epandrial process forming trilobed complex: anterior lobes with rounded apex, apex of posterior lobe flattened with long dense setae; inner base of lobes with short, spine-like process; inner margin connected to internal sclerite formed from lateral expansion of bacilliform and subepandrial sclerites. Surstylus expanded apically with crown of short, stout setae; longer than epandrial process, with long marginal setulae. Cercus slender, thickly sclerotized posteriorly, with inner, apical, dense stout setae.

Female. Similar to male and female of C. attenuatus except as follows: apical half of postpedicel subequal to base; segment 8 of stylus nearly 4× longer than width; lacking av row of setae of fore femur; mid tibia with 2 erect ad and 1 pd seta on basal half. Posterodorsal corner of anepisternum with more expansive dark colouration. Terminalia ( Fig. 122): T10 bearing biserial row of spine-like setae along posterior margin. Cercus bearing spine-like setae, with slender marginal setae. Spermathecal receptacle oval, somewhat flattened with short neck ( Fig. 123).

Distribution. This is the most widespread species of

Ceratomerus in Australia, known from the Atherton Tablelands of northern Queensland to Victoria ( Figs. 29, 124). The northern populations generally appear more pale in colouration .

It is also known from the upper Carnarvon Creek of Carnarvon NP (outlying western locality in southeastern Queensland, Fig. 29). The permanent waters of this montane region in southeastern Queensland are considered an oasis in an area of low and seasonal rainfall (Watson & Theischinger, 1984). Several endemic aquatic taxa are known from this region, or represent distinct populations, separate from the coastal populations.

Biology. This species is readily collected by sweeping emergent rocks in streams from a wide variety of forests, including warm and cool temperate, subtropical, and gallery rainforests. Records indicate that adults can be found year round at most localities.

In southern Queensland, this species inhabits widely disjunct watersheds. During periods of reduced rainfall, the streams occasionally are reduced to large pools, yet C. orientalis remains active. It is this adaptability that has enabled this species to inhabit a range of habitats, resulting in its widespread distribution.

Etymology. The specific name is from the Latin orientalis (of the east), referring to distribution of this species throughout the eastern margin of Australia.

Zoogeography

Faunal subregion

The Ceratomerinae of Australia are presently confined to a narrow eastern zone defined by the Great Dividing Range, extending south into Tasmania. Although there are no records of this subfamily from southwestern Australia, it is clearly another example of a Bassian faunal element ( Spencer, 1896), with a discontinuous northern extension along the temperate tablelands rising from the tropical and subtropical lowlands of northern Queensland ( Mackerras, 1970; Nix, 1991). The distribution of Australian Ceratomerinae could also be termed an element of the Kosciuskan subregion as reviewed by Heatwole (1987) or what Bickel (1994) termed the “Eastern Forest”. However, these two subregions do not include Tasmania. Other Empidoidea with a similar distribution to that of Australian Ceratomerinae , include the Clinocerinae and Hydropeza ( Sinclair, 1999, 2000b). While Apterodromia Oldroyd has a similar distribution, it is also known from southwestern Australia (Sinclair & Cumming, 2000).

Regional patterns

The diversity of Ceratomerinae in Australia is greatest in the southeast, as for many aquatic groups. Although the Border Ranges of northern New South Wales include four species, all represent widespread taxa and no endemic species have been found in this region.

Northern Queensland-Tasmania disjuncts. In the C. campbelli group, there is an example of a widely disjunct sister-species pairing. Ceratomerus campbelli (Tasmania) is clearly most closely related to C. athertonius from the Northern Tablelands on the basis of similar secondary sexual modifications of the male wing. A similar disjunct sisterspecies pair is known also in the aquatic genus Clinocera ( Sinclair, 2000b) .

Areas of endemism. Five of seven species of Ceratomerus are known only from Tasmania (71% endemism). In other aquatic taxa, high Tasmanian species-level endemism is also reported in Blephariceridae (100%), Plecoptera (nr 90%), and Trichoptera (74%) ( Zwick, 1977; Hynes & Hynes, 1982; Williams & Campbell, 1987; Neboiss, 1991). In Odonata, two endemic cold-water genera are known, suggesting long isolation of stream faunas (Watson & O’Farrell, 1991).

Although Tasmania was connected to the mainland during the Pleistocene, the land bridges were primarily low plains, and mostly unfavourable to cool-adapted species ( Hynes & Hynes, 1982; White, 1994). Among other Empidoidea, Tasmanian endemics are also known in terrestrial Apterodromia (100%) and the aquatic genera Hydropeza (100%) and Clinocera (33%) (Sinclair & Cumming, 2000; Sinclair, 2000b). Bickel (1998) estimates that there may be more than 100 Tasmanian species of Hilarini , including an endemic genus, Cunomyia Bickel.

The remarkable diversity of Ceratomerus in Barrington Tops National Park is a reflection of the range in altitude and resulting floral changes found there. Nine species are reported with two species currently endemic, or known only from the Park. Ceratomerus barringtonensis is known from both 480 m and 1280 m, while C. oreas is known only from the Nothofagus region above 1200 m. The southern species, C. maculatus and its northern sister species, C. falcatus are both found here, but the former is recorded only from 1200 m and the latter from the subtropical area at 480 m. The widespread C. orientalis is found from 380 to above 1200 m and the southern species, C. albistylus is found only at higher elevations.

Widespread species patterns. Ceratomerus orientalis is the most widespread species, ranging from northern Victoria to southern Queensland (including Carnarvon NP), with an isolated population in the Tablelands west of Cairns. Most widespread species such as C. orientalis are found in both remnant and gallery rainforests. The latter are surrounded by sclerophyll forests (e.g., Royal National Park south of Sydney). In contrast, although C. albistylus is the second most widespread species ranging from Tasmania to New England National Park, it is recorded mostly from cool, wet rainforests. All species of Ceratomerus with very restricted ranges are confined to remnant rainforests and have not been recorded from gallery rainforests.

Two widespread species in the southeast ( C. albistylus and C. maculatus ) are common at both higher and lower altitudes as far north as Sydney. While populations north of Sydney are confined to areas above 1000 m. In addition, C. lobatus appears to be an example of a Bassian element with coastal populations present primarily in the cooler months. This pattern was discussed by Mackerras (1950).

Norfolk Island. Norfolk Is. is volcanic in origin, located in the southwestern Pacific, between New Caledonia and New Zealand and some 1400 km east of the coast of Australia ( Rentz, 1989). There are three main islands in the Norfolk group, of which the ecologically devastated Philip Is. is 6 km south of Norfolk. It is estimated that the islands are 2.8–3 million years old and the biota could not have existed until after the late Pliocene ( Rentz, 1989).

The present fauna arrived via transoceanic dispersal during the past two million years. During lower sea-level periods associated with Pleistocene glaciation (lowered approx. 100 m), the islands would have still been as isolated as today, although several small stepping stone islands probably existed that aided dispersal ( Holloway, 1977; Rentz, 1989).

There has been no detailed study of the empidoids of Norfolk Is. Bickel (1994, 1996) reported three non-endemic species of Sciapodinae (Dolichopodidae) from Norfolk Is., of which two were probably accidentally introduced. All species also occur in Australia. The single species of Ceratomerus recorded from Philip Is. is clearly of the C. ordinatus group and thus of Australian origin. This species group is not known from New Zealand and no ceratomerines have yet been discovered from New Caledonia (Sinclair, unpubl. data) and the highlands of New Guinea. Additional material, especially males are required to determine the status of this species from Philip Is.