Phyllobaenus corticinus ( Gorham, 1883 )

Leavengood, John M., Gemmill, Robert M., Raber, Brian & Quinn, Michael A., 2012, Notes on the Identification, Distribution, and Natural History of Phyllobaenus Corticinus (Gorham, 1883) (Coleoptera: Cleridae: Hydnocerinae), Including the First Report from the United States, The Coleopterists Bulletin 66 (4), pp. 351-356 : 354-355

Phyllobaenus corticinus ( Gorham, 1883) ( Figs. 1–3 )

Hydnocera corticina Gorham 1883: 173 , tab. IX, fig. 6; Lohde 1900: 92; Schenkling 1908: 702, 1910: 103.

Phyllobaenus corticinus (Gorham) : Corporaal 1950: 58; Papp 1960: 79; Barr 1975: 12.

Original Description and Discussion. See Gorham (1883).

Types. The current location of some specimens from the type series is uncertain (see “Type Locality” below). Gorham (1883) stated “ seven specimens were collected at Las Mercedes [ Guatemala], only one or two in each of the other localities.” Five of the original type-specimens are in the BMNH. Five syntypes from Las Mercedes and one specimen each from one or more of the remaining three localities remain unaccounted. Some syntypes are possibly in the MNHN, where Gorham’ s private collection was deposited. Gorham was known to divide large series among the MNHN, BMNH, MHNG, and the personal collections of Champion , Schenkling, Corporaal, and Sharp. The BMNH specimen from Mexico is herein designated as the lectotype and the known paralectotypes are listed.

Specimens Examined. Types: LECTOTYPE (here designated): Syntype [round label]; Type [round label]; Mexico, Salle Coll.; 592; Type [original label]; B. C. A. Col. III. (2). Hydnocera corticina Gorham , Hyd. corticina Gorham ( BMNH; 1). PARALECTOTYPES (4): Syntype [round label]; El Tumbador, 2500 ft., Champion; figured [label]; B. C. A. Col. III. (2). Hydnocera corticina Gorham ( BMNH; 1); Syntype [round label]; Cerro Zunil, 4– 5000 ft., Champion; B. C. A. Col. III. (2). Hydnocera corticina Gorham ( BMNH; 1); Syntype [round label]; Las Mercedes, 3000 ft., Champion; B. C. A. Col. III. (2). Hydnocera corticina Gorham ( BMNH; 2, sharing a single card mount).

Non-type material: GUATEMALA: Petén: Tikal Parque , 8-9-VI-1991, J. E. Wappes ( NMNH; 1); MEXICO: Campeche: 28 km east of Xpujil, 29- VI-1980, R. H. Turnbow ( RHTC; 1); Chiapas: 5 km NW Coapilla, 1910 m, Malaise trap, [secondary] mesophil forest, LLAMA08 Ma-A-04-2-01, 25-28- V-2008, LLAMA, 17.18224° 93.15179° ( SEMC; 1); Nahá, 960 m, Malaise trap, mesophil forest, LLAMA08 Ma-A-07-2-02, 9-VI-2008, LLAMA, 16.94916° 91.59476° ( SEMC; 2); Lago Metzabok , 575 m, beating vegetation, lowland wet forest, LLAMA08 Go-A-06-2-01, 6-VI-2008, LLAMA, 17.12380° 91.63635° ( SEMC; 1); 8 km SE Salto de Agua, 100 m, Malaise trap, [secondary] wet forest edge, LLAMA08 Ma-A-08-2-01, 14-17-VI-2008, LLAMA, 17.51624° 92.30144° ( SEMC; 1); Sierra Morena, 1360 m, Malaise trap, [secondary] mesophil forest, LLAMA08 Ma-A-01-1-02, 13-V-2008, LLAMA, 16.15988° 93.60565° ( SEMC; 1); 21 km SW Salto de Agua, 180 m, beating vegetation, [secondary] wet forest, LLAMA08 Go-A-08-4-04, 15-VI-2008, LLAMA, 17.38542° 92.42802° ( SEMC; 1); 2 km SE Custepec, 1495 m, Malaise trap, mesophil forest, LLAMA08 Ma-A-02-1-02, 17-24-V-2008, LLAMA, 15.72099° 92.95106° ( SEMC; 1); Guerrero: Amula , 6000’, VIII-1907, H. H. Smith ( BMNH; 1); 6 miles northeast of Tixtla, 16-VII-1984, J. Woolley ( TAMU; 1); Tamaulipas: Altas Cumbres, 12 mi. sw Cd. Victoria, 19-III- 1986, J. C. Schaeffer ( TAMU; 1); Veracruz: Cordoba , 13-VII,, F. Knab ( FSCA; 1); Río Metlac Canyon , 4 km south of Fortín, 900 m elevation, 17-VII- 1990, J. K. Liebherr ( JPHC; 1); Fortin de las Flores , 23-XII-1963, L. B. and C. W. O’ Brien ( WOPC, to be transferred to FSCA; 1); USA: Texas: Cameron County: Brownsville, Sabal palm grove on Sabal texana fronds, 7-III-2009, R. M. Gemmill ( RMGC; 5); Cameron County: Sabal palm grove , 19-X-2008, Riley, Raber and Heffern ( DHPC; 6); Cameron County: Sabal palm grove , 10-X-2009, Heffern and Raber ( DHPC; 1); Cameron County: Sabal Palm Grove Ref. (site 11) , beating dead palm fronds, 25.85601° 97.41726°, 18-X-2008, E. G. Riley ( TAMU; 3); Cameron County: Sabal Palm Grove Ref. (site 11) , beating open re-vegetated area, 25.85601° 97.41726°, 4-IV-2009, E. G. Riley ( TAMU; 1); Cameron County: Sabal Palm Grove Ref. (site 11) , beating open re-vegetated area, 25.85601° 97.41726°, 7-III-2009, E. G. Riley ( TAMU; 2); Cameron County: Sabal Palm Grove Ref. (site 10) , palm forest, beating etc., 25.84964° 97.41798°, 5-VI-2010, E. G. Riley ( TAMU; 1); Cameron County: Sabal Palm Grove Ref. (site 1) , Lindgren funnel , palm for., 25.84799° 97.41881°, 3-18-IX-2009, King and Riley ( TAMU; 2); Cameron County: Sabal Palm Grove , beat palm fronds, re-vegetated area, 25.85601° 97.41726°, 7-II-2009, Raber, Riley and Heffern ( RABER; 18); Cameron County: Sabal Palm Grove , beat palm fronds, re-vegetated area, 25.85601° 97.41726°, 9-X-2009, B. Raber and D. Heffern ( RABER; 1); Cameron County: Sabal Palm Grove , X-29/30–2011, Raber, Riley, and Heffern, 25.85601° N, 97.41726° W, beat palm fronds, re-vegetated area ( RABER; 3).

Type Locality. Mexico. The paralectotypes (and remaining syntypes) were collected from El Tumbador (Dept. San Marcos) and Las Mercedes and Cerro Zunil (Dept. Quetzaltenango), Guatemala.

Distribution. Southern Texas (Cameron County), Mexico (Campeche, Chiapas, Guerrero, Tamaulipas, Veracruz), and Guatemala (Petén, Quetzaltenango, San Marcos) ( Gorham 1883:173; Schenkling 1908: 702).

Diagnosis. Elytra strongly convex (especially apically) with conjointly rounded apices; head, pronotum, and basal half of elytra largely red (as in Fig. 3 ) (with some darker variations; as in Figs. 1–2 ), but lacking white maculae in the basal elytral third; legs always bicolored, appearing banded, although reddish bands often incompletely spanning the circumference. Phyllobaenus corticinus is most similar in color pattern to Phyllobaenus tricolor (Schaeffer) and Phyllobaenus knausii (Wickham) , both of which are distinguished by independently rounded elytral apices, a rather flat elytral surface, and uniformly red legs. Isohydnocera albocincta (Horn) has similar elytral form, but differs in having two white maculae in the basal third of each elytron. Darker forms of P. corticinus (with no red) are very similar to Phyllobaenus vitrinus (Gorham) , which differs in its distinctly carinate elytral humeri.

Comments on Variation. All specimens collected in Texas (e.g., Fig. 3 ) have the entire head, pronotum, and basal half of the elytra red (unquestionably not ferruginous). They most closely resemble the paralectotype from El Tumbador. Other specimens from the type series ( Figs. 1–2 ) have variable coverage of dark integument on the basal half of the elytra, prothorax, and head. The LLAMA specimens (eight from Chiapas) have the greatest color variation, with the basal half of the elytra ranging from red, dark cloudy red, or black with limited red maculae, to entirely black, with the head and pronotum likewise variable. The apical sixth of the elytra ranges from black with very sparse silvery white setae ( Fig. 3 ) to white with dense silvery setae ( Figs. 1–2 ). The five observed types and the LLAMA and Texas specimens are most consistent in leg coloration. The degrees of midelytral constriction and acuteness of the pronotal tubercles vary considerably.

Biology. Phyllobaenus corticinus appears to be strongly associated with living and (less commonly) dead fronds and inside the corrugations of Sabal mexicana Martius (= Sabal texana (Cook)) (Arecaceae) , whose common names include Texas palm/palmetto, Mexican palmetto, Rio Grande palmetto, and hat palm ( Figs. 4–5 ). This palm species is native to southern Texas and the coasts of Mexico, Honduras, El Salvador, and Guatemala (www.floridata.com/ref/s/saba_mex.cfm). All Texas specimens were collected from a palm grove where this clerid was “not especially rare…but…only found in association with [ Sabal mexicana ] (Dan Heffern, in litt.; Robert Gemmill, in litt.).”

Like other Hydnocerinae , P. corticinus is an ant mimic ( Leavengood 2010), much like sympatric species of Euderces LeConte and Tetranodus Linell (Cerambycidae) which are also common in the Sabal Palm Grove area, but not associated with palms. Forty-one of the 43 Texas specimens were taken from the palms, mostly from living fronds, in new growth areas ( Fig. 4 ), but no specimens were taken from flowers on the palms. Because Texas palms in older growth areas have living fronds and inflorescences that are out of reach of collectors ( Fig. 5 ), it is uncertain if P. corticinus has a preference for new growth areas (Dan Heffern, in litt.).

Adults of this species have been collected almost year-round (February–October, December; from all sources). In Cameron County, Texas, adults have been collected from February to October (February– April, June, September– October). Some Texas specimens have been collected in Lindgren funnel traps in an old growth area of the Sabal Palm Grove (label data). However, almost all Texas specimens were collected from palms in an open re-growth area of the Sabal Palm Grove (E. G. Riley, in litt.).

Generic Assignment. Gorham (1883) included Hydnocera corticina Gorham in a group with Hydnocera intricata Gorham , Hydnocera nigroaenea Gorham, Hydoncera cyanipennis Gorham, and Hydnocera cincta Gorham , all of which shared the characters “elytra covering the abdomen; shoulders not carinate.” We do not consider that these two characters necessarily represent synapomorphies of a species-group. This group was “section B i” in Gorham’ s work in the BCA. “Section B ii” included Hydnocera cryptocerina Gorham , Hydnocera impressa Gorham , Hydnocera bituberculata Chevrolat , and Hydnocera quadrilineata Chevrolat. Gorham (1886) later included Hydnocera rudis Gorham and Hydnocera vitrina Gorham in “B” without specifying section (i or ii), with H. rudis appearing to be ill-placed. However, he did not include Hydnocera cylindricollis Gorham , the specimens of which he had originally confused for section B species H. bituberculata . Gorham noted that H. cylindricollis , which he placed in section A, has the carina sharply defined, which would place it in B ii if the elytra cover the abdomen (which they do). This was an error on Gorham’ s part and H. cylindricollis should have been assigned to section B ii.

Gorham’ s species-groups should not be mistaken for natural groups. The elytral form of H. nigroaenea is quite different from that of the other members of its group (B i). Likewise, H. rudis and H. quadrilineata differ in elytral form from other species in B ii. It is expected that further investigation will reveal that these three species should not be associated with the others of B i and B ii, respectively, and that the elytral form of the remaining species (and others not assessed by Gorham) discussed above should represent a monophyletic assemblage.

All members of Hydnocera Newman (excluding species later assigned to Wolcottia Chapin or Isohydnocera Chapin ) are recognized as Phyllobaenus Dejean. Wolcott (1944) explained the status of Hydnocera (a junior synonym, in part, of Phyllobaenus ) in great detail. The placement of H. corticina in Phyllobaenus by Corporaal (1950) created some confusion, since Phyllobaenus has bifid tarsal ungues,whereas Isohydnocera has simple tarsal ungues. Phyllobaenus corticinus has simple tarsal ungues, but otherwise appears closely associated with many species now recognized as Phyllobaenus . Despite its utilization in several faunal keys ( Knull 1951; Dillon and Dillon 1972; Downie and Arnett 1993; Leavengood 2008b), we consider tarsal ungal bifidity alone to be an ill-suited character for generic delimitation. Kolibáč (1998) synonymized Cephaloclerus Kuwert under Phyllobaenus and Isohydnocera under Wolcottia . We consider that these changes were made in the absence of sufficient understanding of variation within these genera, and we therefore choose not to accept Kolibáč’ s reclassification. Currently, P. corticinus remains assigned to Phyllobaenus and no generic changes are proposed herein.

Figures

Figs. 1–5. Phyllobaenus corticinus. 1) Lectotype, Mexico; 2) Paralectotype, Cerro Zunil; 3) Non-type (RMGC), Cameron County; E. G. Riley in 4) New growth area and 5) Old growth area in the Sabal Palm Grove Sanctuary, Cameron County, Texas.