Cymatodera caterinoi Rifkind and Burke, 2019

Rifkind, Jacques, 2019, New Species of Flightless Cymatodera Gray, 1832 (Coleoptera: Cleridae: Tillinae) from the California Channel Islands, The Coleopterists Bulletin 73 (3), pp. 551-557 : 553-556

Cymatodera caterinoi Rifkind and Burke , new species

Zoobank.org/ urn:lsid:zoobank.org:act:E64B0790-3894-4D12-86AA-0700298138C3 ( Figs. 3–4 , 11–20 )

Specimens Examined. Holotype: CA: Santa Barbara Co. / 33°59’53”N, 119°43’12”W / Santa Cruz Island / Islay Canyon / X–20–2001; M. Caterino / under bark Quercus (SBMN) . Paratypes: 1 ( SBMN) , same data as holotype; 1 ( SBMN), CA : Santa Barbara Co. / 34°00’31”N, 119°39’30”W / Santa Cruz Island, Del Norte Cmpgrd. / X–19–2001; M. Caterino / beaten from Quercus ; 1 ( CSCA), CA : Santa Barbara Co. / 34.0150°N, 119.7967°W / UC Santa Cruz Island Res. / nr. Centinela ; v.12.2009 / Caterino, Chatzimanolis, / Hopp & Polihronakis, colls., // CA BEETLE PROJ CBP0095041 ; 1 (SBMN), CA: Santa Barbara Co., 33.9992°N, 119.77275°W, UC Sta Cruz Isl. Res. / vi–5–2005, M. Caterino / & J. Jacobs // CA BEETLE PROJ CBP0030336 ; 1 ( LACM), Santa Cruz Is, Cal / VIII–16– [19]34 // 1939–765 // Collected by / Lloyd Martin // Los Angeles Museum / Channel Islands / Biological Survey ; 1 ( CASC), California / Santa Cruz Island / Central Valley // 23- 26-iv-1976 / Ex. Quercus sp. / A. J. Mayor; 1 ( LACM), Santa Cruz Island , Santa Barbara Co. // 20-iii-1941 / G. P. Kanakoff; 1 ( UCRC), GRIFFIN CYN / Santa Cruz Island , CA / Santa Barbara County / 16 APR. 1983 // Univ. Calif. Riverside // Ent. Res. Museum / UCRC ENT 148827 ; 1 (JNRC), CA: Santa Barbara Co. / 33.9850°N, 120.0764°W / CINP : Santa Rosa Island / Windmill Cyn. FIT / iv.22–28.2008, M. S. Caterino // CA BEETLE PROJ CBP0078369 ; 1 (JNRC), same data as preceding, except: CA BEETLE PROJ CBP0078398 ; 1 (SBMN), SANTA ROSA ISLAND / S. Barbara Co. CALIF . / 1976 23 / Feb. / Ranch Beecher’ s Bay // P. W. Collins & W. G. Abbott, collectors; 1 ( CASC), CA : Santa Barbara Co. / 34.0040°N, 120.0914°W / CINP : Santa Rosa Island / Lobo Cyn. , iv.25.2008 / M. S. Caterino // CA BEETLE PROJ CBP0078815 ; 1 (JNRC), CA: Santa Barbara Co. / 33.9850°N, 120.0764°W / CINP : Santa Rosa Island / Windmill Cyn. , Malaise trap / iv.22–28. 2008, M. S. Caterino // CA BEETLE PROJ CBP0079084 ; 1 (SBMN), CA: Santa Barbara Co. / 33.9850°N, 120.0764°W / CINP : Santa Rosa Island / Windmill Cyn. / cantharidin pitfall / iv.22–28. 2008, M. S. Caterino // CA BEETLE PROJ CBP0078131 ; 1 (SBMN), CA: Santa Barbara Co. / 34.0040°N, 120.0914°W / CINP : Santa Rosa Island / Lobo Cyn. , Malaise trap, iv.23–26. 2008, M. S. Caterino // CA BEETLE PROJ CBP0078260 ; 1 (JNRC), CA: Santa Barbara Co. / 34.0053°N, 120.0901°W / CINP : Santa Rosa Island / Upper Lobo Cyn. / vi.15.2007 / Caterino & Chatzimanolis // CA BEETLE PROJ CBP0069666 ; 1 (CSCA), CA: Santa Barbara Co. / 33.9765°N, 120.0111°W / CINP : Santa Rosa Island / Box Cyn. / iv.26.2008, M. S. Caterino // CA BEETLE PROJ CBP0078004 ; 1 ( LACM), East Anacapa Island / Ventura Co. / California // 21-viii-1978 / S. E. Miller .

Diagnosis. Cymatodera caterinoi , C. vandykei , and C. angustata are similar, although the males of all three species can be readily distinguished by virtue of their uniquely shaped pygidia ( Figs. 7–12 ). In dorsal aspect, males of C. caterinoi have the last abdominal tergite with the posterior margin feebly oblique on each side, weakly bisinuate, and with a pair of acuminate spines at the middle that frame a narrow median notch ( Figs. 11 , 16 ), whereas in C. vandykei the hind margin is broadly rounded or subtruncate, and sometimes slightly inflected at the middle ( Fig. 7 ). Cymatodera angustata males have the posterior margin deeply, arcuately emarginate ( Fig. 9 ). The male pygidia of C. caterinoi and C. insularis are more closely similar, but in C. caterinoi the median notch on the posterior margin of tergite 6 is set between acute projections ( Figs. 11 , 16 ), and the produced lateral lobes of abdominal ventrite 6 each bear a dorsal spine at their base ( Figs. 12 , 17 ). The two insular species appear to be allopatric: C. caterinoi is restricted to the Northern Channel Islands (Santa Cruz Island, Santa Rosa Island, and Anacapa Island), whereas C. insularis is confined to the Southern Channel Islands (Santa Catalina Island and San Clemente Island). Female specimens of both species are best identified

through collection data and by association with male specimens.

Description. Holotype male. Length: 10.0 mm. Form: Elongate; apterous ( Figs. 3–4 ). Color: Reddish brown; head somewhat darker; elytra, except posterior fifth, mostly paler, with irregular testaceous banding at base, medially, and ante– apically; sides also paler on posterior 2/3; femora infuscate at distal third to half. Head: Measured across eyes, wider than pronotum; antennae rather elongate, extending past elytral base when laid alongside ( Fig. 15 ); surface densely, moderately deeply punctate and rugulose, moderately densely clothed with short, adpressed, pale setae, interspersed with fewer, longer, suberect pale setae. Pronotum: Longer than broad, broadest across anterior margin; surface shiny, sculptured as on head, moderately densely clothed with short, adpressed, pale setae, interspersed with fewer, longer, suberect pale setae. Elytra: Elongate (ratio of length to maximum width 3:1), narrowed at anterior margin (apterous form), expanded posteriorly, broadest at approximately posterior fourth; apices very broadly, separately rounded and dehiscent; surface shiny, coarsely, deeply punctate, with punctures arranged in 10 longitudinal rows; dorsal series of rows with punctures irregularly interrupted and less deeply impressed posterior to middle; all rows obsolete at posterior sixth, replaced there by shallow dimpling; vestiture as on pronotum, but less densely arrayed and rather inconspicuous. Venter: Metasternal surface shiny, impressed with small, scattered punctures and bearing 2 small, infuscate tubercles ( Fig. 18 ). Abdominal surface shiny, finely, densely subpunctate. Pygidium as in Figs. 11–12 , 16-17 ; last tergite with sides broadly, arcuately tapered laterally to slightly oblique hind angle; posterior margin weakly bisinuate, bearing acicular projections on either side of median notch; last ventrite arcuately emarginate posteriorly at middle, lobate laterally, with lobes wedge-like and bearing a short spine on internal dorsal margin. Aedeagus: Sclerotized; ratio of length of parameres to whole tegmen 0.38:1; tegmen partially covering phallus; parameres feebly developed, pointed at apex; phallobase rather narrow; phallus with copulatory piece truncate distally; phallic plate with 2 rows of denticles, finely granulate on lateral margins; phallobasic apodeme short, slender; endophallic struts slender apically ( Fig. 20 ).

Variation. The female lacks metasternal tubercles, and the pygidium is unmodified, with the last tergite and ventrite small and scutiform, their posterior margins narrowly, conjointly rounded ( Fig. 19 ). Specimens exhibit some variation in the ratio of dark to light elytral patterning ( Fig. 13 ).

Etymology. The specific epithet is a patronym honoring Michael Caterino for his many contributions to our knowledge of California beetles.

Distribution. Known from the Northern Channel Islands of California, specifically Santa Cruz Island, Santa Rosa Island, and Anacapa Island.

Natural History. Specimens were collected under oak bark, in Malaise traps, and in a baited pitfall trap. Cymatodera is known to be predaceous in both larval and adult stages.

Discussion. Although the majority of the fauna and flora of the California Channel Islands is also represented on the nearby California mainland, the islands have been isolated long enough to be home to many endemic species ( Caterino et al. 2015). And while some of these endemics are relicts that formerly inhabited the mainland, others, derived from mainland stock, clearly speciated in situ ( Philbrick 1967; Caterino et al. 2015). Because the two related apterous mainland Cymatodera species are so broadly distributed and have adapted to habitat substantially the same as that found on the Channel Islands, it seems unlikely that the insular C. insularis and C. caterinoi represent relictual, formerly more widespread species. More likely, they evolved as a result of isolation from mainland populations, or possibly derived from colonizing individuals rafted from the mainland or adjacent islands. Caterino et al. (2015) discuss the biogeographical implications of the divergent geological histories of the northern and southern Channel Islands, noting that the close relationships of several northern island endemics is a probable consequence of the Pleistocene agglomeration of the four northern islands into a single superisland (Santarosae) as a result of lowered sea levels. The disjunct distribution of the two Cymatodera species described here conforms to this pattern and may reflect similar origins.

Figures

Figs. 1–4. Cymatodera insularis, holotype male: 1) Dorsal habitus; 2) Lateral habitus. Cymatodera caterinoi, holotype male: 3) Dorsal habitus; 4) Lateral habitus.

Figs. 5–12. Cymatodera species, male pygidia. C. insularis: 5) Dorsal view; 6) Ventral view. C. vandykei: 7) Dorsal view; 8) Ventral view. C. angustata: 9) Dorsal view; 10) Ventral view. C. caterinoi: 11) Dorsal view; 12) Ventral view.

Figs. 13–20. Cymatodera caterinoi, paratypes. 13) Male habitus; 14) Male abdomen, ventral view; 15) Antenna; 16) Last tergite of male, dorsal view; 17) Last ventrite of male, ventral view; 18) Male metasternum, showing tubercles; 19) Female pygidium, ventral view; 20) Aedeagus.