Corresponding author: Thomas H. Atkinson (
Academic editor: D. E. Bright
Three new species in the genus
The genus
The most noteworthy character of the genus is the presence of paired horns on the male epistomal process. In all species the 2 horns are apparently distinct from their base to their apex. In some species the horns are short and widely separated (
Along with the development of the epistomal horns there has been a parallel anteroventral elongation of the head, particularly in males. This is evident even in species with relatively short horns (
In most groups of the Scolytinae (sensu
Many specimens in collections are covered with a crust of plant resins and boring dust. This can be cleaned off by soaking in acetone or ethyl acetate overnight, combined with gentle ultrasonic cleaning. Once cleaned the elytral surface of all species is shining. At the same time, the interstrial surface of the disc is generally irregular. Strial punctures (and sometimes interstrial punctures) are usually deep, although the striae themselves are generally not impressed. Granules are frequently associated with interstriae on the declivity (
While each species is host specific, generally at the genus level, collectively they are found in a variety of totally unrelated hosts. Hosts include pines (2 species),
All species, so far as is known, are monogynous, with galleries constructed by a single pair. Which sex initiates galleries is unknown. In cases where multiple generations breed in the same piece of host material it is not known whether beetles emerge upon maturity and re-enter host tissues or whether new galleries are initiated without emerging. Galleries of several species have been described by
The following abbreviations are used for museums where specimens are deposited: USNM (U.S. National Museum), TAMU (Texas A&M University), FSCA (Florida State Collection of Arthropods), CAS (California Academy of Sciences), CEAM (Centro de Entomología y Acaralogía, Colegio de Postgraduados, Montecillo, México).
This species is named in honor of Steve Wood, especially appropriate considering the large number of species in this genus that he described. It is easily recognized by its widely separated, short epistomal horns and by the large, uniform granules associated with all interstrial and strial punctures on the disc to its base and on the declivity, except for striae and interstriae 1 and 2.
Male. Color black. Length 1.4–1.6 mm, width 0.6–0.7 mm, length/width 2.3. Epistomal horns short, length 2–3× basal diameter, widely separated by distance greater than length; without any associated setae. Frons weakly concave from epistoma to upper level of eyes; concavity without raised margin dorsally or laterally; surface of concavity smooth, impunctate; setae sparse, short, most abundant on periphery of concavity. Antenna subcircular, sutures slightly procurved. Pronotum with asperities concentrated near middle; summit at posterior margin, not strongly pronounced; some asperities on postero-lateral areas; area of greatest concentration of asperities not sharply demarcated laterally. Striae deeply punctured; all punctures associated with rounded granules to base of elytra; granules occupying entire space between adjacent punctures. Interstriae 1.5× as wide as striae; setae uniseriate, each associated with a rounded granule to base. Granules on striae and interstriae similar in size. Declivity steep, rounded posteriorly, strongly sulcate. Striae 1 and 2 impressed; granules absent; punctures smaller than on disc; granules also absent from associated interstriae. Interstriae 3 narrowly elevated, forming a distinct crest; its granules larger than on disc. All other declivital striae and interstriae similar to those of disc. Lateral elevations highest in middle, projecting beyond apex of elytra in lateral view.
Female. Frons flattened, surface sparsely punctured, setose in central area. Other characters identical to those of males.
HOLOTYPE (male): “MEXICO: Baja California, Isla San Esteban, 6-V-1985, THA-289,
This species has been collected in the dried ribs of its host cacti. As is the case with most other cactus-breeding species, successful breeding occurs in portions of stems that have dried out to a hard, yellowish color, without the black discoloration associated with decay. This situation most commonly occurs in erect, dead stems still attached to the host. In pieces that fall to the ground the upper surface is apparently too hot from direct exposure to the sun and the lower surface seems likely to decay from contact with the soil. Galleries are initiated at the areoles, clumps of spines that are found along the ridges of the ribs.
This species is readily distinguished from other species with short, separated epistomal horns by the nearly flat male frons with only a narrow, longitudinal sulcus. This frontal sulcus is the basis for the specific epithet.
Male. Color black. Length 1.4–1.7 mm, width 0.6–0.7 mm; length / width 2.4. Epistomal horns short, pointed, height slightly greater than basal diameter; located near center of epistoma, separated by 1.5× height. Frons flattened with narrow longitudinal sulcus in center, not wider than the distance between the horns. Surface sparsely punctured, with short setae; setae and punctures more abundant on periphery. Asperities on anterior margin tooth like, widely separated, becoming more abundant, flatter, and densely packed towards center and summit. Asperities are tightly packed, and slightly overlapping in a triangular pattern in the center and posterior of the pronotum, but less densely spaced asperities are abundant in posterolateral areas to the posterior margin. Striae not impressed, punctures deep, spaced within row by distance equal to their own diameters. Interstriae 1.5× as wide as striae with shallow uniseriate punctures. Vestiture of short strial setae and longer, erect interstrial setae, becoming longer posteriorly. Declivity steep, sulcate, with lateral elevations strongly elevated in middle, posterior margin rounded. All interstriae except 1–2 with rounded, uniseriate granules beginning at base of declivity. Punctures on striae 1 and 2 smaller than on disc. Lateral elevations very wide, consisting of elevated portions of interstriae 3–5.
Female. Frons transversely impressed above epistoma, convex above, surface sparsely punctured, setose in central area. Epistoma with low calluses in same position as male horns. Other characters identical to those of males.
5–7
11–14
17–18
HOLOTYPE (male): “ MEXICO: Sonora, Isla Tiburón, 14-V-1985, THA-301,
The habits of
This species most resembles
Male. Color black. Length 1.8–2.1 mm, width 0.7–0.9 mm, length / width 2.45. Epistomal horns long, projecting to middle of prothorax, fused along their length except for the terminal ¼. Frons horizontally concave, flattened laterally with small concave area in center; surface sparsely punctured, mostly without setae. Anterolateral margins of the epistoma with short, downward projecting spine near base of antennal insertion. Antenna elongate, 1.7 times longer than wide, sutures straight. Pronotum with asperities widely separated at anterior margin, most abundant in center; arranged in sharply defined triangular pattern with no asperities or granules in posterolateral portions. Clearly defined summit at posterior margin, strongly elevated into a point, projecting backwards over elytra. Striae not impressed, with deep punctures, separated by less than their own diameter. Interstriae not elevated, about twice as wide as striae; surface irregular, with numerous, fine, confused punctures. Vestiture of recumbent, short, strial setae, with long, ribbon-like interstrial setae, these longer than distance between rows. Declivity weakly sulcate, gradual, slightly acuminate posteriorly. Interstriae 1 and 2 wider on declivity than on disc. Punctures on striae 1 absent beyond declivital base, interstriae 1 and 2 with numerous, small, confused punctures. Interstrial granules on all other declivital interstriae except 1. Interstriae 2 strongly elevated, its granules slightly longer and sharper than those on other interstriae.
Female. 2 wide calluses present on epistoma, frons transversely impressed above. Frons shallowly concave above transverse impression, surface with shallow, large, closely set punctures. A fringe of setae along upper and lateral margins of convavity. Other characters identical to those of males.
HOLOTYPE (male): “Mexico: Mexico (state), Teotitlán, 2-VI-1982, 2,410 m, leaves
This species has been collected on 3 occasions in the central Mexican highlands from the large semi-domesticated agaves used historically for pulque production. These plants reach a very large size with individual leaves reaching a length of 1.5 m or more and armed with strong, recurved spines. The insect is found in dead, mostly dry leaves at the bottom of the rosette. In a healthy plant, the only way to get to these leaves is to basically take the plant apart, something that requires a lot of work and potential loss of blood on the part of would-be collectors. It is more easily collected from rosettes that are dying and beginning to fall apart after blooming, or in the occasional specimen growing on the edge of a terrace or wall such that the lower leaves can be reached. The beetles may enter the leaves from either the top or bottom surface and galleries resemble those described by
Information on hosts and distribution is included in the key as a general aid to users. Distributional information should only be used in a very general sense given that many species are still known only from type localities.
1 | Asperities on pronotum large, chisel-like, forming distinct triangle with apex at posterior margin, clear demarcation between this area and posterolateral portions of pronotum, most asperities posterior to middle ( |
14 |
– | Asperities on pronotum small, often granulate, more evenly distributed, not in clearly marked triangular pattern, apex indistinct or not strongly projecting backwards; most asperities anterior to middle ( |
2 |
2(1) | Male epistomal horns clearly separated at base ( |
3 |
– | Male epistomal horns contiguous at base and fused along lower ? or more of length ( |
6 |
3(2) | Epistomal horns 4–5 times longer than basal diameter, separated by less than half their length; frons deeply concave, abruptly margined at top. 1.3–1.6 mm. Jalisco | |
– | Epistomal horns less than twice basal diameter ( |
4 |
4(3) | Epistomal horns about twice as long as basal diameter, separated by more than twice their length; frons shallowly concave; prominent granules on all declivital striae and interstriae to base. 1.4–1.6 mm. In |
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– | Epistomal horns about as long as basal diameter, separated by slightly more than height; granules restricted to posterior portion of elytra and declivity | 5 |
5(4) | Male frons concave over entire area between eyes, concavity extending beyond upper level of eyes; lateral convexities on declivity weakly elevated. 1.5–1.9 mm. Oaxaca | |
– | Male frons flattened, with narrow, shallow longitudinal impression from epistoma to upper level of eyes; lateral convexities on declivity abruptly, strongly elevated. 1.4–1.7 mm. In |
|
6(2) | Granules present at least on posterior portion of discal interstriae as well as on declivity | 7 |
– | Granules on elytral interstriae and /or striae restricted to declivity | 8 |
7(6) | Frons deeply concave, concavity occupying entire distance between eyes, wider above eyes; declivity moderately sulcate, granules present on all interstriae. 1.6–1.8 mm. Jalisco | |
– | Frons less deeply concave, concavity occupying 80% of distance between eyes, not wider above eyes; declivity deeply sulcate, interstriae 1 and 2 shining, without granules. 1.3–1.6 mm. Oaxaca | |
8(6) | Frons deeply concave, concavity occupying 90–100% of distance between eyes | 9 |
– | Frons shallowly concave or flattened, concavity if present occupying 60% or less of distance between eyes | 11 |
9(8) | Upper part of concavity of frons wider above eyes, upper margin acute; declivity more pronounced, interstriae 2 narrowed, without granules except near base | 10 |
– | Upper part of frontal concavity not wider above eyes, upper margin less pronounced; declivity shallower, interstriae 2 not narrowed, with granules for its full length. 1.3–1.5 mm. In |
|
10(9) | Upper half of frons bearing longitudinal carina; apex of pronotal summit not developed into backwards-projecting cone. 1.5–1,8 mm. In |
|
– | Upper half of frons without longitudinal carina; apex of pronotal summit developed into backwards-projecting cone. 1.4–1.7 mm. Puebla, Oaxaca | |
11(8) | Frons curved in lateral profile, but flat longitudinally; pronotal asperities weakly developed; declivity with relatively few, small granules on interstriae. 1.2–1.4 mm. Puebla. ( |
cactophthorus Wood |
– | Frons weakly to prominently concave in central area between eyes; pronotal asperities larger; declivity with prominent granules on interstriae 2 and higher | 12 |
12(11) | Horns reaching or exceeding upper level of frons, apical portions digitate, divaricate; interstria 1 on declivity not deeply impressed, lateral elevations not pronounced. 1.5–1.6 mm. In |
|
– | Horns not reaching upper level of frons, outer sides parallel to apex, interstria 1 on declivity strongly impressed, lateral elevations prominent | 13 |
13(12) | Frons with prominent concavity in middle of frons; outer sides of horns parallel, inner sides angled making obvious “V” shape; antennal sutures straight. 1.6–1.9 mm. In |
|
– | Frons shallowly concave, concavity not well defined; inner sides of horns not strongly angled; antennal sutures bisinuate. 1.4–1.7 mm. In |
|
14(1) | Declivity strongly sulcate, lateral elevations armed with teeth larger than granules on other interstriae, sutural interstriae depressed, widened prominently in middle; interstriae 2 curved outwards in compensation | 15 |
– | Declivity weakly or not sulcate, sutural interstriae not widened on declivity, interstriae 2 not curved outwards | 19 |
15(14) | Declivity with obvious teeth on interstriae 2 on lateral margin of declivity much larger than granules present on other interstriae | 16 |
– | Declivity with granules on interstriae 2 only slightly larger than those on other interstriae | 17 |
16(15) | Horns 1.5–2 times as long as frons; apex of pronotal asperities strongly pronounced, backwards projecting; teeth on interstriae 2 flattened laterally, height greater than twice basal width. 1.6–2.1 mm. In |
|
– | Horns shorter, slightly longer than length of frons; apex of pronotal asperities not strongly pronounced; teeth on declivital interstriae 2 cone shaped, about 1.5 times as high as basal width. 1.4–1.7 mm. In |
|
17(15) | Body slender, 2.6 times longer than wide; interstriae 1 strongly impressed, sulcate anterior to declivity. 1.6–2.0 mm. In phloem of of |
|
– | Body stouter, 2.4 times longer than wide; interstriae not impressed or sulcate anterior to declivity | 18 |
18(17) | Frons weakly concave, impunctate; interstriae 1 and 2 on declivity not widened, granules on interstriae 2 small, rounded, restricted to base. 1.6–2.3 mm. In |
|
– | Frons weakly flattened longitudinally, densely, finely punctured; interstriae 1 and 2 on declivity widened in middle, granules on interstriae 2 larger than those on other interstriae, pointed, present to apex. 1.8–2.1 mm. In dry fleshy leaves of |
|
19(14) | Declivity with coarse granules on interstriae 1–3. 1.3–1.8 mm. In |
SW U.S. |
– | Declivity without granules on interstriae 1–3 | 20 |
20(19) | Horns short, not reaching top of frons; elytral punctures shallow; granules not present on declivity, declivity narrowly sulcate. 1.3–1.5 mm. In leaves of |
|
– | Horns longer, exceeding top of frons; elytral punctures deeper; declivity not sulcate. 1.3–1.5 mm. In phloem of of |
New collection records are only shown if they represent significant geographic range extensions or new host associations.
27–31
Previously known only from the type locality in Hidalgo from “giant cactus”. Mexico: San Luís Potosí: Hwy 57, 18 km S intersection Hwy 80; 22.76227 N, 100.49222 W; 6-VII-2009; 1,422 m; branches of
Previously known only from the type locality in Oaxaca from “giant cactus”. Mexico: Querétaro: Hwy 57D, 15 km N intersection Hwy 45D; 20.67390 N, 100.3046 W; 2,048 m; 6-VII-2009; dry stems of
Reported previously from southern California in the U.S. and from the Mexican states of Baja California and Sonora. Mexico: Baja California Sur; San José del Cabo, 11 mi SW; 28-VI-1967; blacklight; E.L. Sleeper, E.M. Fisher (CAS-1); BCS: Santa Victoria, 27/28-X-1968; 800’; blacklight; E.L. Sleeper, F.J. Moore (CAS-1); BCS: Loreto, 3 mi N; 10/11-XI-1968; blacklight; E.L. Sleeper, F.J. Moore (CAS-1)
33–34
Previously the only known hosts were tropical trees and shrubs of the genus
This species has previously been reported from Los Angeles and Ventura Counties in southern California. CA: San Diego Co., Oak Grove Campground, Cleveland N.F.; 3-XII-1991;
Reported previously from the states of San Luís Potosí and Hidalgo. New Records: Mexico: Nuevo León: Hwy 57, y mi S. Entronque Roberto; 20-VI-1983; 1,768 m; from dry
This article would not have been possible without the help and support of Steve Wood, particularly for the gift of specimens of a large number of species of