Laemosaccus rileyi Hespenheide, 2019

Hespenheide, Henry A., 2019, A Review of the Genus Laemosaccus Schönherr, 1826 (Coleoptera: Curculionidae: Mesoptiliinae) from Baja California and America North of Mexico: Diversity and Mimicry, The Coleopterists Bulletin (MIMICRY AND LAEMOSACCUS In an earlier paper (Hespenheide 1996), I presented the hypothesis that species of Laemosaccus of the L. nephele group with red humeral spots on the elytra were Batesian mimics of members of the Chrysomelidae in the subfamily Clytrinae. There is no evidence that Laemosaccus species are distasteful, and what is either L. nephele and / or L. obrieni have been reported as prey items of birds (Beal 1912). In Cave Creek Canyon, Cochise County, Arizona, 21 forms (species and “ subspecies ”) of Clytrinae were hypothesized to be the primary models of 22 species of mimics in the families Anthribidae (one species), Bruchidae (two species), Buprestidae (four species), Chrysomelidae, subfamily Cryptocephalinae (three species), Coccinellidae (six species), Curculionidae, subfamily Baridinae (one species), and Laemosaccus (five species). Of these, the coccinellids and the cryptocephaline chrysomelids are probably distasteful Mullerian co-mimics. Ecologically, the species of Laemosaccus co-occurred with their clytrine models on both desert legumes and canyon oaks, although more clytrine species occurred in the desert and more Laemosaccus species occurred in the canyons. Species of clytrines showing the mimetic pattern are common throughout Mexico (Bellamy 2003, who renamed the Mexican buprestid genus Acherusia Laporte and Gory, 1837 as Mimicoclytrina Bellamy to reflect their resemblance to clytrines), but decline in numbers of species and in the proportion of the clytrine fauna through Central America to Panama (Hespenheide 1996, fig. 2). Laemosaccus seems to follow a similar pattern. Mimicry is more common in large faunas, especially in wet tropical areas (Hespenheide 1986, 1995); because the largest clytrine fauna is in Mexico, the clytrine mimicry complex is also larger there (Hespenheide 1996). This complex has more members than I first enumerated and deserves further study. The evolution of mimicry produces resemblances between unrelated species (Laemosaccus and other putative mimics, with clytrines and perhaps other Chrysomelidae and Coccinellidae as models; see Hespenheide 1976, 1996) and selects against the divergence of related species. In Batesian mimicry - hypothesized to be the form of relationship between Laemosaccus and clytrines - the selection for precision of mimicry is stronger on the mimic (Laemosaccus), so that resemblances among them should be closer, regardless of ancestry. Close morphological resemblances based on ecology rather than ancestry may be termed mimetic homoplasy (Hespenheide 2005) and can make recognition of species difficult (as in Laemosaccus) or complicate phylogenetic analyses. I have speculated (Hespenheide 1996) that the sympatric “ subspecies ” of the clytrine models (Moldenke 1970) may in fact be reproductively isolated sibling species. It will be interesting to see whether or not genomic studies show the closeness of relationships among Laemosaccus species that the morphology suggests) 73 (4), pp. 905-939 : 930-931

Laemosaccus rileyi Hespenheide , new species

Zoobank.org/ urn:lsid:zoobank.org:act:4595970B-4343-4687-B778-7143B66E4165 ( Figs. 15 , 26 )

Description. Holotype Male. Length 2.25 mm, width 1.05 mm ( Fig. 15 ). Subcylindrical in cross section, regularly rounded behind, more narrowly so in front, black except each elytron with large, oval, red-orange posthumeral spot from 3 rd interval from lateral margin to 2 nd interval from suture; head, pronotum, elytra, and propygidium glabrous, thorax and abdomen ventrally with punctures each with a small, relatively inconspicuous, silvery seta, setae inconspicuous on legs, hair-like and semi-erect on tergite 8. Head hemispherical, 0.50 mm wide, rostrum rounded-terete, punctate, with short, shiny, medial groove, 0.35 mm long, antennae inserted at middle. Pronotum globose, convex at base, slightly constricted before anterior margin, 0.7 mm long, 0.9 mm wide, broadest at basal third, with lateral margins very arcuately rounded, coarsely, evenly punctate, punctures rounded and separate, with fine medial carina for entire length. Elytra distinctly wider than pronotum at base, margins parallel, 1.4 mm long, 1.05 mm maximum width, elytral striae much narrower than intervals, striae finely punctate, intervals angulate-carinate, interval 3 weakly toothed on middle third. Abdominal ventrite 1 with setae hair-like and less conspicuous at midline; ventrite 5 twice as long at lateral margins than at middle. Profemora with strong, acute ventral tooth beyond middle, meso- and metafemora with small tubercles at same position. Genitalia as in Fig. 26 ; aedeagus 0.70 mm long.

Allotype Female. As male but 2.55 mm long, 1.25 mm wide; setae beneath more conspicuous, except nearly glabrous at middle of abdominal ventrite 1; rostrum subcylindrical, polished, very finely, inconspicuously punctate, 0.45 mm long; tergite 7 weakly convex, coarsely punctate, glabrous.

Specimens Examined. Holotype: Texas: Brewster Co., Big Bend National Park, (middle) Pinnacles Trail , ca. 6400’, 29°15’13”N 103°17’56”W, 21.06.2004, E. G. Riley-49 ( TAMU) . Allotype: Texas: Brewster Co., BBNP , (lower) Pinnacles Trail , ca. 5,900’, 29°15’32”N 103°17’52”W, 21.06.2004, E. G. Riley-48 ( TAMU) . Paratypes: USA: Texas: Barrel R [an] ch., 25.07.43, H. P. Smith (1, LACM) ; Brewster Co., Alpine , 11.07.1938, R. H. Beamer (1, SEMC) , Chisos Mts. , 19.07, J. W. Green (2, CASC) , 17.07.1946, D. J. & J. N. Knull (1, OSU) ; Chisos M., sweeping on road to Basin , 10.06.1968 (1, CHAH) ; Big Bend National Park, Maple Canyon , 5200’, 29.06.1982, R. S. Anderson (1, CMNC) ; Big Bend National Park, Lost Mine Trail , 6000–6850’, 29°16’N 103°15’W, 29.06.1982, 9.07.1982, R. S. Anderson (2, CMNC) ; BBNP, Laguna Meadow- Colima Trails , 6500–7000’, 29°14’29”N 103°18’36”W, 2.08.2003, E. G. Riley (13) (5, TAMU) ; same data as holotype, (2, TAMU) ; BBNP, (upper) Pinnacles Trail , ca. 6900’, 29°15’06”N 103°17’52”W, 21.06.2004, E. G. Riley-50 (1, TAMU) ; same data as allotype (1, TAMU) ; BBNP, Window Trail , (upper), 29°16’29”N 103°19’01”W, 21.06.2004, E. G. & C. M. Riley- 03 (1, TAMU) ; Culberson Co., Pine Springs , 12- 15.07.1928, W. Benedict (1, SEMC) , 12.06.1971, C. O’ Brien, night, Quercus (1, ASUHIC) ; Jeff Davis Co., 4, 6.07.1953, D. J. & J. N. Knull (2, OSU) ; 5 mi. N Ft. Davis , 14.07.1956, H. & A. Howden (1, CMNC) ; Davis Mts. , 2.06.1951, 3.07.1955, D. J. & J. N. Knull (1, OSU) , 25.06.1959, D. J. & J. N. Knull (1, CHAH) , 11.07.1958, W. F. Barr (1, WFBM) , 1.07.1977, E. Giesbert (1, EMEC) ; Madera Cyn., Davis Mts. , 11.07.1958, W. F. Barr, at light (1, CMNC) , Davis Mts Resort , 28.06/ 2.07.1986, Heffern, Heuther & Androw (1, SEMC) .

Other Specimens Examined. USA: Arizona: “Arizona,” Kunze (1, FMNH) , Morrison (1, USNM) ; [Coconino Co.], Williams, 29.07, Wickham (1, USNM) , 30.06, 16, 19, 20.07, Barber & Schwarz Coll. (6, USNM) ; Flagstaff , 1.08.1933, J. D. Beamer (1, SEMC) , 21.08.1929, W. Lynn (1, SEMC) . New Mexico: Lincoln Co., 2.7 mi. N Alto , 7200’, 19.06.1982, G. A. P. Gibson, sweeping oak (2, CMNC) ; [Otero Co.], 2 mi. S Cloudcroft , 5.06.1969 (2, BYU) ; Sandoval Co., C. C. Hoff, B-486 (1, AMNH) ; Santa Fe Co., Ca ~ nada de los Alamos , 8 mi. SSE Santa Fe, 2360m, 35°36’N 105°51’W, 23.vi.2000, H. A. Hespenheide, on Quercus gambelli (2, BMNH, CHAH) . Mexico: San Luis Potos´ı : 32 mi. E San Luis Potos´ı, 26.07.1970, Murray, Phelps, Hart, Schaffner (1, TAMU) .

Hosts. Adults in Texas and New Mexico were collected on Q. gambelli and other oaks.

Etymology. This species is named in honor of the collector of the types and many other specimens of Laemosaccus, Edward G. Riley , retired, of Texas A&M University.

Discussion. This is the smallest species of Laemosaccus and is most similar to L. obrieni . Laemosaccus rileyi has the posthumeral spot placed farther posteriorad, is proportionately shorter in habitus and the male rostrum, usually has a small postscutellar patch of setae, and different male genitalia. Only collections from Texas are included in the type series, but although the specimens from Texas and Arizona are widely separated, collections from New Mexico suggest it is more widely distributed in northern and eastern Arizona and western New Mexico, areas that are poorly collected to date. A specimen from Arizona is illustrated on Bug- Guide (bugguide.net/node/view/1471142bgimage; also images 1471143 and 1471144). Males from the type series in western Texas vary in length from 2.20 to 2.70 mm (mean = 2.42 mm, n = 18); females from 2.05 to 3.30 mm (mean = 2.70 mm, n = 18).

Figures

Figs. 13–18. Laemosaccus species, dorsal habitus. 13) L. clytrinoides; 14) L. howdenae; 15) L. rileyi; 16) L. vaurieae; 17) L. westcotti; 18) L. texanus.

Figs. 25–30. Laemosaccus species. Dorsal and lateral views of aedeagus and paramere: 25) L. browerorum; 26) L. rileyi; 27) L. vaurieae; 28) L. westcotti; 29) L. peninsularis; 30) L. texanus, dorsal and lateral views of aedeagus only. 31) L. peninsularis, dorsal habitus.