REVISION OF DACNOCHILUS LECONTE

ANNALS OF CARNEGIE MUSEUM 15 may 2013

Vol. 81, numbEr 2, PP. 73–117

REVISION OF DACNOCHILUS LECONTE (=ACALOPHAENA SHARP) (COLEOPTERA: STAPHYLINIDAE: PAEDERINAE) EstEban JiménEz-sánchEz Departamento de Zoología y Antropología Física (Biología Animal), Facultad de Veterinaria, Universidad de Murcia, 30071 Murcia, España Laboratorio de Zoología, FES-Iztacala, Universidad Nacional Autónoma de México, 54090, Tlalnepantla, Estado de México, México [email protected]

José Galián Departamento de Zoología y Antropología Física (Biología Animal), Facultad de Veterinaria, Universidad de Murcia, 30071 Murcia, España [email protected]

ABSTRACT The New World rove beetle genus Dacnochilus LeConte, 1861, is revised. Cladistic analysis of 29 characters of adult morphology and male genitalia indicates that Acalophaena Sharp, 1884, is paraphyletic in relation to Dacnochilus. The monophyly of Acalophaena + Dacnochilus is supported by five synapomorphies: 1) labrum with broad, deep emargination; 2) three or more rows of punctures on elytral disk; 3) epipleural carina present; 4) lateral macrosetae on head, pronotum, and elytron of medium size, and 5) the lateral sclerites of tergum IX large, narrow, and sharp ended. A revised concept of Dacnochilus, inclusive of Acalophaena, treats Acalophaena Sharp, 1884, as a new synonym of Dacnochilus LeConte, 1861, with twelve new combinations for species formerly placed in Acalophaena: Dacnochilus angularis (Erichson, 1840), Dacnochilus argentina (Bernhauer, 1912), Dacnochilus basalis (Lynch, 1884), Dacnochilus bruchi (Bernhauer, 1927), Dacnochilus bruchiana (Bernhauer, 1933), Dacnochilus compacta (Casey, 1905), Dacnochilus germana (Sharp, 1876), Dacnochilus horridula (Casey, 1905), Dacnochilus macularis (Erichson, 1840), Dacnochilus obscurior (Bernhauer, 1933), Dacnochilus pagana (Sharp, 1876), and Dacnochilus polita (Sharp, 1876). Twelve new species of Dachnochilus are described: D. atrus, D. bilobatus, D. ecuatoriensis, D. grandioculus, D. huautlae, D. megistothorax, D. nahuiollinae, D. newtoni, D. nigrapicalis, D. rociae, D. xilonenae, and D. zaragozae. Five new synonyms are established: Acalophaena laevipennis Bernhauer, 1908, and Acalophaena longipennis Bernhauer, 1933, are new junior synonyms of Dacnochilus basalis (Lynch, 1885); Acalophaena daguerrei Bernhauer, 1933, is a new synonym of Dacnochilus bruchi (Bernhauer, 1927); Lithocharis picta Sharp, 1876, is a new junior synonym of Dacnochilus pagana (Sharp, 1876); Dacnochilus fresnoensis Leech, 1939, is a new junior synonym of Dacnochilus laetus LeConte, 1863. A neotype is designated for Lithocharis macularis Erichson, 1840. Lectotypes are designated for seven species: Lithocharis angularis Erichson, 1840; Acalophaena argentina Bernhauer, 1912; Acalophaena bruchi Bernhauer, 1927; Lithocharis germana Sharp, 1876; Dacnochilus laetus LeConte, 1863; Lithocharis pagana Sharp, 1876; Lithocharis polita Sharp, 1876. The distributions of most species are mapped. An identification key and illustrations of structural features including aedeagi are provided. The geographical distribution of species is documented with new records from many New World countries. KEy Words: Acalophaena basalis, Dacnochilus laetus, distribution, hosts, lectotypes, neotype, new species, paraphyletic, synonyms.

INTRODUCTION Acalophaena Sharp, 1884, and Dacnochilus LeConte, 1861, are rove beetles (Coleoptera: Staphylinidae) belonging to the tribe Paederini (Paederinae: Paederini: subtribe Lathrobiina). A phylogenetic treatment of generic and suprageneric taxa in Paederinae is lacking, and this complicates a meaningful delimitation of historically proposed subtribes (Sharp 1885, 1886; Casey 1905; Blackwelder 1939, 1943, 1944). Acalophaena ranges from southern U.S.A. to northern Argentina, and Dacnochilus is distributed from southern U.S.A. to Central America (Sharp 1886; Bernhauer and Schubert 1912; Blackwelder 1939, 1944). These beetles are rare and therefore very few species are well represented in collections. Although comprehensive biological information on the group is lacking, observations indicate that several species are attracted to light traps, suggesting they may be nocturnal. Some species are associated with ants (Sharp 1876; Bernhauer 1927, 1933) and termites (Lynch 1885).

The presence in Acalophaena of a pair of well or slightly developed teeth at both sides of the median broad notch of the labrum, a feature absent in Dacnochilus, is the main difference used to distinguish them (Lynch 1884; Sharp 1886; Newton et al. 2001). Casey (1905) considered Acalophaena to be a more specialized form, with a broad compact body and large setae at the sides, and considered Dacnochilus to be more closely related to Linolathra Casey, 1905, a genus-group name currently synonymized with Pseudolathra Casey, 1905, a subgenus of Lobrathium Mulsant and Rey, 1878 (Newton et al. 2001). Casey (1905) also compared Dacnochilus laetus LeConte, 1863, with two species he described, Acalophaena compacta and Acalophaena horridula, in order to recognize more reliable characters to separate those genera. Casey noted that although these species were more similar to the type species of Acalophaena, A. basalis (Lynch, 1884), there was great variation among the known species of Acalophaena

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Fig. 1.—One of four most parsimonious trees (length = 110, consistency index = 48, retention index = 72) that depicts phylogenetic relationships among Dacnochilus species with consistent characters states plotted (black circles, synapomorphic characters; open circles, homoplastic characters). Numbers above circles are characters. Numbers below circles are character states. Bootstrap support values greater than 50% are shown on appropriate branches.

from Mexico and South America. Some of these have a slender body and broader neck, and Casey suggested they might belong to other genera. The purpose of this paper is to provide a systematic revision of Dacnochilus and Acalophaena, and to test the monophyly and validity of the generic names based on a phylogenetic analysis.

Taxonomic History The genus Dacnochilus was described by LeConte (1861) for which D. laetus was established as the type species by subsequent monotypy in 1863. The type species was described from “Carolina” and Lousiana (U.S.A.), but later recorded from Mexico and Guatemala (Sharp 1886; Blackwelder1944). The other described species of Dacnochilus

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Fig. 2.—Adult head and mouthparts of Dacnochilus. A–D, D. huautlae, new species: A, head, dorsal view; B, mandibles; C, antenna; D, labrum, teeth (to), emargination (e), anteclypeus (ac). E–F, left mandible: E, D. laetus; F, D. bruchiana. G–H, antenna: G, D. rociae, new species; H, D. bruchiana. I–J, labrum: I, D. ecuatoriensis, new species; J, D. laetus. K–L, D. huautlae, new species: K, right maxilla, ventral view; L, labium, dorsal view. Abbreviations: cd, cardo; ep, epicranium; fm, foramen magnum; g, glossae; ga, galea; ge, genae; hp, hypopharynx; la, lacinia; pg, paraglossae; pc, postclypeus; ps, puncture; oc, occiput; st, stipes; tp, temple.

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is D. fresnoensis Leech, 1939, described from Fresno, California (U.S.A.). Other records in U.S.A. for both species were cited by Newton et al. (2001): D. laetus from Florida through Texas, and D. fresnoensis from southern California and Arizona. Navarrete-Heredia et al. (2002) recorded D. laetus in Mexico from Guanajuato, Morelos, Puebla, and Veracruz. Newton et al. (2001) and Navarrete-Heredia et al. (2002) both mention an additional described species of Dacnochilus from Venezuela but without giving an explicit name. Lynch (1884) established the genus Calophaena with Calophaena basalis as the type species by monotypy from Buenos Aires, Argentina. Sharp (1886) stated that this name was a junior homonym of Calophaena Klug, 1821 (in Coleoptera: Carabidae) and proposed the replacement name Acalophaena. Sharp (1886) transferred two species described in Lithocharis Dejean, 1833, to Acalophaena: Lithocharis macularis Erichson, 1840, a species known exclusively from Venezuela (Erichson 1840; Bernhauer and Schubert 1912); and Lithocharis angularis Erichson, 1840, from México, Guatemala, Nicaragua, Colombia, and Venezuela (Erichson 1840; Sharp 1886). Navarrete-Heredia et al. (2002) mentions A. angularis in Mexico, specifically the states of Chiapas, Nuevo León, and Veracruz. Sharp (1886) also transferred the following species, all known from Brazil, from Lithocharis to Acalophaena: L. polita Sharp, 1876; L. pagana Sharp, 1876; L. germana Sharp, 1876; L. picta Sharp 1876. Acalophaena picta is also recorded from Argentina (Sharp 1886; Blackwelder 1944). Casey (1905) described A. horridula Casey, 1905, from Mexico (Veracruz), and A. compacta Casey, 1905, from the United States (Arizona). Acalophaena compacta has been recorded in Nevada (Moore and Legner 1975) and from several localities in California (Caterino and Chatzimanolis 2007). Finally, between 1908–1933 Bernhauer described seven taxa from Argentina: A. laevipennis Bernhauer, 1908; A. argentina Bernhauer, 1912; A. bruchi Bernhauer, 1927; A. bruchiana Bernhauer, 1933; A. daguerrei Bernhauer, 1933; A. longipennis Bernhauer, 1933; and a variety, A. polita var. obscurior Bernhauer, 1933 (Blackwelder, 1944). Bernhauer and Schubert (1912) cited A. macularis as D. macularis. Later, Blackwelder (1939) cited A. angularis as D. angularis. Blackwelder (1944) included both D. angularis and D. macularis in his checklist. The attribution of those species to Dacnochilus is probably due to Solsky’s proposal (1868) to transfer the species originally named Lithocharis macularis and L. angularis to Dacnochilus (Lynch 1885) because he did not consider relevant the presence of a pair of teeth on the labrum, a character considered diagnostic for Acalophaena. Nonetheless, Lynch (1885) and Sharp (1886) considered this character to have merit, and the latter author transferred these species to Acalophaena together with the Lithocharis species previously mentioned.

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MATERIALS AND METHODS Dry specimens were first relaxed in warm soapy water. The last two abdominal segments were dissected and cleared using 10% KOH, heated for several minutes before dissecting the aedeagus. All disarticulations of each specimen were stored in microvials with glycerin and attached to the pin bearing that specimen. The exemplars were examined with a Zeiss Stemi 2000-C stereoscopic microscope. Illustrations were made using a photographic digital system (SPOT Insight FireWare Camera) installed on the microscope; measurements were made on the digital images using SPOT software (ver. 4.6.3.8). Multiple photos in dorsal view of the species were montaged with CombineZM (Hadley 2006). Micrographs from a scanning electron microscope were obtained using a JEOL-6100. Distribution maps were generated using ArcView GIS (ver. 3.2), based on coordinate data (latitude and longitude) obtained from Google Earth ver. Beta (2007), from GPS data taken directly in the field, and in a few cases from information on specimen labels. Locality data for exemplars mentioned in the Biologia Centrali Americana were taken from Selander and Vaurie (1962). Imprecise locality data for some specimens were not considered when mapping distributions. All measurements used in the descriptions were taken as greatest dimensions for a given structure along both length and width axes. In specimens where it was not possible to measure in this way because of the position of the structure, length was standardized as the sum of subcomponent lengths. The measurements are expressed as arithmetic means with standard deviation, the number of specimens (N), and minimum and maximum values (±). Terms for structural features follow Sharp (1876, 1886) and Blackwelder (1936). For each species the following information is included: 1) a detailed description; 2) a diagnosis as a comparison with most similar species with emphasis on characters that identify both sexes (males from most species can be readily identified by examining the aedeagus and sternum VIII); 3) distribution; 4) biology (under this heading is summarized the biological data taken from specimen labels such as habitat, host, altitude, seasonal information, and observations in the field); 5) remarks (about type specimens); 6) type material; and 7) material examined. Label data from type specimens are cited verbatim. A slash mark ( / ) indicates the end of text on each label. Information about type specimen labels is given, such as color of label paper (other than white), printing (handwriting; color of ink other than black), label shape (other than rectangular), brief comments (if mounted with host), and the collection acronym (in parentheses). For the Material Examined section, locality data, date of collection, and collector’s names are given with the number of specimens and collection abbreviation in parentheses. Countries are organized geographically from north to south, then alphabetically by states and provinces.

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Collection Abbreviations

Phylogenetic Analysis

Some specimens examined in this study were obtained during field trips in Mexico and Argentina, 2004–2007, but most of the material was borrowed for research from the following insitutional and private collections: AMNH, American Museum of Natural History, New York, U.S.A. BMNH, The Natural History Museum, [formerly British Museum (Natural History)], London, UK CASC, California Academy of Sciences, San Francisco, California, U.S.A. CMNH, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, U.S.A. CNIN, Colección Nacional de Insectos, Instituto de Biología, UNAM, México DEI, Deutsches Entomologisches Institut, Müncheberg, Germany EMEC, University of California, Essig Museum of Entomology, Berkeley, U.S.A. FESI, Colección Entomológica de la Facultad de Estudios Superiores Iztacala, UNAM, México FMNH, The Field Museum of Natural History, Chicago, U.S.A. IMLA, Instituto de Entomología, Fundación Miguel Lillo, Tucumán, Argentina INPA, Instituto Nacional de Pesquisas da Amazoonia, Colecão Sistemática da Entomologia, Brazil, Amazonas, Manaus, Brazil ISNB, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium JLN, Private collection of José Luis Navarrete-Heredia, México MACN, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Buenos Aires, Argentina MCZ, Museum of Comparative Zoology, Harvard University, Cambridge, U.S.A. MLPA, Universidad Nacional de La Plata, Museo de la Plata, La Plata, Argentina MNHUB, Humboldt-Universität zu Berlin Museum für Naturkunde, Berlin, Germany PJC, Private collection of Peter Jump, U.S.A. SBMNH, Santa Barbara Museum of Natural History, Santa Barbara, California, U.S.A. SDNHM, San Diego Natural History Museum, San Diego, California, U.S.A. SEMC, Snow Entomology Collection, KU Natural History Museum, Lawrence, Kansas, U.S.A. SMNS, Staatliches Museum für Naturkunde, Stuttgart, Germany UCRC, University of California, Entomology Research Museum, Riverside, California, U.S.A. UM, Colección de Coleópteros de la Universidad de Murcia, Murcia, Spain USNM, Smithsonian Institution, National Museum of Natural History, Washington D.C., U.S.A.

Twenty-four species historically placed in Acalophaena and one species of Dacnochilus were included in the phylogenetic analysis. Specimens from the genera Neomedon Sharp, 1886, and Achenomorphus Motschulsky, 1858 (Paederini: Medonina), were used as outgroups. A total of 29 characters from adult morphology (Appendix 1) were included in the cladistic analysis. All characters were equally weighted, the multistate characters were considered unordered (non-additive). Characters 2, 11, and 14 are parsimony uninformative and were not included for calculating CI (consistency index). A character state matrix (Table 1) was constructed using WinClada version 0.9.99 (Nixon 1999) and submitted to NONA version 2.0 (Goloboff 1993) to reconstruct phylogenetic relationships by maximum parsimony using a heuristic search option with the following settings: multiple TBR + TBR; max trees to hold = 1000; replications = 1000; 10 starting trees for replication. ACCTRAN optimization was applied, a method favoring reversals when the options are equally parsimonious. Bootstrap support values for nodes were obtained using 1000 replicates. RESULTS Cladistics Four equally parsimonious trees were obtained with a length of 110, consistency index of 0.48, and retention index of 0.72 (Fig. 1). The four trees differ in the placement of D. angularis, D. grandioculis, D. huautlae, D. polita and D. xilonenae. These species form a basal polytomy in all four trees. Acalophaena is paraphyletic with respect to Dacnochilus. The latter as D. laetus is placed in the clade (D. obscurior (D. laetus (D. argentina (D. germana ((D. bruchiana, D. megistothorax, new species) ((D. macularis, D. rociae, new species) (D. ecuatoriensis, new species (D. bruchi, D. pagana)))))))). The monophyly of the two genera together is supported by a single synapomorphy, (29-2) apex of internal sac pointed, and by three homoplasies: 1) (12-1) mandible narrow and long; 2) (13-1) two teeth on mandible; and 3) (21-0) epipleural carina absent. We therefore propose that Acalophaena be considered a synonym of Dacnochilus. The monophyly of Acalophaena + Dacnochilus in the basal node is supported by five synapomorphies: 1) (10-0) labrum with a broad, deep emargination; 2) (20-0) with three or more rows of punctures on the elytral disc; 3) (211) the epipleural carina present; 4) (23-1) medium size of lateral macrosetae on the head, pronotum, and elytra; and 5) (24-1) lateral sclerites of tergum IX large, narrow, and sharp ended. A single homoplasy supports the monophyly of these two genera: (5-1) the eye as long or slightly longer than the temple. The synapomorphies above are the main argument


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Table 1. Character state matrix for species of Dacnochilus and outgroups. Inapplicable character states are coded “-”. 1 2 3 1234567890 1234567890 123456789 Character State Values Achenomorphus sp. Neomedon sp. Dacnochilus laetus Dacnochilus angularis Dacnochilus argentina Dacnochilus atrus, new species Dacnochilus basalis Dacnochilus bilobatus, new species Dacnochilus bruchi Dacnochilus bruchiana Dacnochilus compacta Dacnochilus ecuatoriensis, new species Dacnochilus germana Dacnochilus grandioculis, new species Dacnochilus horridula Dacnochilus huautlae, new species Dacnochilus macularis Dacnochilus megistothorax, new species Dacnochilus nahuiollinae, new species Dacnochilus newtoni, new species Dacnochilus nigrapicalis, new species Dacnochilus obscurior Dacnochilus pagana Dacnochilus polita Dacnochilus rociae, new species Dacnochilus xilonenae, new species Dacnochilus zaragozae, new species

supporting the monophyly of Acalophaena + Dacnochilus. However, the characters used in this analysis do not provide sufficient phylogenetic resolution (bootstrap values less than 50%) to unambiguously support relationships between species. The only clade with sufficient support (89%) was the group containing D. bruchiana and D. megistothorax. The inclusion of new data, perhaps DNA sequences, should greatly strengthen future analyses of relationship. Color Variation Color is a character highly variable within some species, and this explains the creation of several synonyms, for example within D. basalis, D. bruchi, and D. laetus. For species with enough exemplars to assess color variation, there are three that are defensibly polychromatic: D. obscurior, D. rociae, and D. laetus. For D. obscurior, three color morphs were described, of which Morph 2 and Morph 3 have numerous locality records over a wide region (Fig.

0100000021 0000001101 1011001100 0000101000 0000000100 0010001110 1000101100 0000101000 2011100110 2010012110 1011001110 2000100110 1000000110 0000201000 0010101110 0000101100 0000100110 1010012110 0010001010 0011001120 1010001110 1000001100 2000000110 1000101100 1000100100 1000101000 0011101110

3000000002 2110200102 0111000100 1000000100 1110000100 1000011011 1000012013 1000000000 1110110113 1120010100 1000011113 1110100100 1110000100 1000000100 1000011011 1000000100 1110000100 1110000100 1000011013 1000011011 1000011003 1000000100 1110100100 1000000100 1110000100 1000000100 1000011011

0022-0005 00021- - - 001102313 101100000 001121312 100002210 101001411 101102401 000122123 010021334 100000300 001121322 001121312 101100010 100000300 101100000 001121402 010021302 000000210 100000313 000002400 101100211 001121123 101100300 001121402 101100300 100000300

14D); the altitudinal occurrence of these morphs suggest a relationship between color and altitude. Both morphs are reddish, but Morph 2 is darker than Morph 3 (Figs. 11A– B). The darker Morph 2 ranges from sea level to 500 m altitude, and the paler Morph 3 is found from 500 to 2000 m. This pattern of altitudinal chromatic variation has been observed for other staphylinids (Chatzimanolis 2004). The greatest color variation was shown by D. rociae with four described morphs (Figs. 12A–D). These have a restricted altitudinal record from sea level to 400 m, and color and altitude do not appear to be correlated. Spatial distribution of the four morphs is not totally segregated, complicating analysis (Fig. 15A). Based on the color differences, D. laetus and D. fresnoensis have been considered to be distinct species. The former species has the base of the elytron black (Fig. 12F) and in the latter the elytron is completely reddish (Fig. 12G). Even though they have allopatric distribution (Fig. 13E ), both species have identical morphology, including the genitalia and sternum VIII in males. They are here synonymized as one species (D. laetus) with

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Fig. 3.—Thoracic structures of Dacnochilus. A–E, pronotum, dorsal view: A, D. huautlae, new species; B, D. basalis; C, D. bruchiana; D, D. newtoni, new species; E, D. argentina. F–G, elytron of D. huautlae, new species, male: F, lateral view; G, dorsal view. H, scutellum of D. huautlae, new species, male. I–N, legs and tarsi of D. huautlae, new species, male: I, oblique ctenidia on inner side of protibia; J, protarsomeres, dorsal view; K, protarsomeres, ventral view; L, mesotarsus; M, metatarsus; N, apex of metatibia. Abbreviations: a, apex; b, base; ce, outer ctenidium; ci, inner ctenidium; ec, epipleural carina; ed, elytral disk; ep, epipleura; es, elytral suture; h, humerus; ps, prescutum; sc, scutum; ss, spatulate setae.


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two distinctive color morphs. The color pattern of Morph 4 of D. rociae is very similar to D. germana (Figs. 12D–E), and these two taxa are sympatric in southeastern Bolivia (Figs. 15A–B). This is the only case where both sexes are readily separable, the males by the shape of the eight sternite and aedeagus, and the females by the shape of tergite X (Figs. 4D–E). Other species with similar color patterns are Morph 1 of D. obscurior, D. xilonenae, and D. polita (Figs. 10H, 11C–D); these should be distinguished by male sexual characters. Based on the available data, the geographical distribution of these three species is not overlapping. There is some allopatry between D. obscurior and D. xilonenae in southeastern Bolivia, but it involves Morph 2 of D. obscurior (Figs. 14C–D). KEY TO SPECIES OF DACNOCHILUS USING EXTERNAL GENITALIA OF MALES The key below is based mainly on features of males, and coloration was only used for those species that do not show variation in color. The aedeagus is species-specific, and is the only character that permits reliable identification of the species. In some cases the emargination of sternum VIII in males is useful to distinguish between similar species. The females of species with similar coloration can be identified only through association with males because no variation was found in female genital segments, except between D. rociae, new species, and D. germana. 1.

Labrum without teeth, sides of median notch rounded D. laetus LeConte (p. 101)

1’.

Labrum with pair of teeth, or at least acute projections, at sides of median notch 2

2(1’).

Without punctures on elytral disk, or with one or two longitudinal rows 3

2’.

With three or more longitudinal rows of punctures on elytral disk (Fig. 3G) 11

3(2).

Lateral margin of pronotum concave (Fig. 3B) D. basalis (Lynch) (p. 91)

3’.

Lateral margin of pronotum convex or straight (Figs. 3C–E) 4

4(3’).

Elytron without epipleural carina

4’.

Elytron with epipleural carina (Fig. 3F) (sometimes only weakly marked in the apex) 7

5(4).

Elytron with oblique dark mark; head and pronotum with dark irregular marks or completely reddish-brown (Fig. 9B) D. bruchi (Bernhauer) (p. 92)

5’.

6(5’).

Head brown; abdomen entirely reddish-brown (Fig. 9C); aedeagus with apex of the paramere without preapical constriction (Fig. 6D) D. nahuiollinae, new species (p. 106)

6’.

Head reddish-brown; abdomen with segments VII–VIII dark (Fig. 9D); aedeagus with apex of paramere with slightly preapical constriction (Fig. 6E) D. nigrapicalis, new species (p. 107)

7(4’).

Head reddish-brown (Fig. 9E) D. compacta (Casey) (p. 94)

7’.

Head dark

8(7’).

Elytron completely reddish-brown or with brown small mark near the base, or elytron yellowishbrown with brown mark covering almost all of the elytral disk; elytral disk without or with one longitudinal row of punctures 9

8’.

Elytron completely black or brown with hind outer angle reddish-brown; outer half of elytral disk with two rows of punctures 10

9(8).

Elytron completely reddish-brown or with brown small mark near the base (Fig. 9F); elytral disk without longitudinal row of punctures; aedeagus with apex of internal sac shaped as a simple lobe (Fig. 6G) D. zaragozae, new species (p. 114)

9’.

Elytron with brown mark on most of disk, with epipleura and outer hind angle yellowish-brown (Fig. 9G), external half of elytral disk with one longitudinal row of punctures; aedeagus with apex of internal sac triangle-shaped with upper vertex rounded (Fig. 6H) D. newtoni, new species (p. 107)

8

10(8’). Elytron completely black (Fig. 9H); male sternum VIII with broad emargination V-shaped (Fig. 5I); aedeagus with apex of paramere truncate, apex of internal sac as simple lobe, slender and long (Fig. 6I) D. atrus, new species (p. 88) 10’.

5

Elytron with basal half dark; head brown or reddish-brown; pronotum reddish-brown 6

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Elytron brown with hind outer angle reddishbrown (Fig. 10A); male sternum VIII with shallow curved emargination (Fig. 5J); aedeagus with apex of paramere rounded, apex of internal sac as simple lobe, broad and short (Fig. 7A) D. horridula (Casey) (p. 100)

11(2’). Antenna filiform (Fig. 2H) 11’.

12

Antenna gradually and slightly broader to apex (Figs. 2C, 2G) 13

12(11). Elytron with oblique dark mark from fore outer angle to hind inner angle; head completely reddish-brown (Fig. 10B); male sternum VIII with broad shallow straight emargination (Fig. 5K); aedeagus with apex of paramere rounded with


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slightly preapical constriction, apex of internal sac pointed (Fig. 7B) D. megistothorax, new species (p. 106) 12’.

Elytron with dark mark on the basal half extending to inner hind angle; forehead with brown marks (Fig. 10C); male sternum VIII with broad curve emargination (Fig. 5L); aedeagus pearshaped, apex of paramere rounded, apex of internal sac M-shaped (Fig. 7C) D. bruchiana (Bernhauer) (p. 93)

13(11’). Pronotum slightly wider than long (measured along midline), subhexagonal (Fig. 3A); apex of tergum X without spine (Fig. 4F); 7–10th antennomeres approximately 1.5 times as long as wide, subrounded (Fig. 2C); mandible broad at base with more than two teeth (Fig. 2B); with epipleural carina (Fig. 3F) (except in D. xilonenae, new species where carina is faint or absent) 14 13’.

Pronotum slightly longer or as long as wide, subrounded to subquadrate (Fig. 3E); apex of tergum X with spine (Figs. 4C–E); 7–10th antennomeres 1.5x longer than wide, subparallel (Fig. 2G); mandible narrow at base with two teeth; without epipleural carina 20

14(13). Head dark 14’.

15

Head reddish-brown (some specimens of D. obscurior have a dark mark on head) 18

18’.

Elytron with dark mark variable in shape

19’.

16’.

Elytron with at least the basal half dark

17

17(16’). Elytron dark with hind outer angle reddish-brown (Fig. 10F); male sternum VIII with broad Vshaped emargination (Fig. 5O); aedeagus with apex of paramere emarginate, apex of internal sac with simple lobe (Fig. 7F) D. angularis (Erichson) (p. 84) 17’.

Elytron dark at its basal half and apical half reddish-brown (Fig. 10G); male sternum VIII with shallow V-shaped emargination (Fig. 5P); aedeagus with apex of paramere rounded with preapical constriction, apex of internal sac bilobed and broad (Fig. 7G) D. bilobatus, new species (p. 92)

18(14’). Aedeagus with apex of internal sac bilobed and slender D. obscurior (Bernhauer) (p. 108)

Male sternum VIII with deep U-shaped emargination (Fig. 5S); aedeagus with apex of paramere rounded, apex of internal sac as broad simple lobe (Fig. 8A) D. polita (Sharp) (p. 111)

20(13’). Labrum with teeth barely developed (Fig. 2I) D. ecuatoriensis , new species (p. 96) 20’.

Labrum with teeth well developed (Fig. 2D)

21

21(20’). Head completely dark; elytron dark with hind outer angle reddish-brown 22 21’.

Head completely reddish-brown or with irregular dark marks; elytron with different coloration 23

22(21). Pronotum subrounded (Fig. 3E); male sternum VIII with deep broad U-shaped emargination (Fig. 5U); aedeagus with apex of paramere rounded; apex of internal sac pointed (Fig. 8C) D. argentina (Bernhauer) (p. 88) 22’.

16

16(15’). Elytron with oblique dark mark from fore outer angle to hind inner angle (Fig. 10E) D. grandioculus, new species (p. 98)

Aedeagus with apex of internal sac as simple lobe 19

19(18’). Male sternum VIII with shallow and straight emargination (Fig. 5R); aedeagus with apex of paramere rounded, apex of internal sac as simple lobe (Fig. 7I) D. xilonenae, new species (p. 114)

15(14). Elytron completely reddish-brown (Fig. 10D) D. huautlae, new species (p. 100) 15’.

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Pronotum subquadrate; male sternum VIII with broad and straight emargination (Fig. 5V); aedeagus with apex of paramere rounded and with preapical constriction; apex of internal sac triangular with upper apex rounded (Fig. 8D) D. macularis (Erichson) (p. 104)

23(21’). Mentum with protuberance D. pagana (Sharp) (p. 110) 23’.

Mentum without protuberance

24

24(23’). Male sternum VIII with broad and straight emargination (Fig. 5X); aedeagus with apex of paramere rounded with preapical constriction, apex of internal sac pointed (Fig. 8F); female tergum X transverse (Fig. 4D) D. rociae, new species (p. 112) 24’.

Male sternum VIII with deep U-shaped emargination (Fig. 5Y); aedeagus with apex of paramere rounded without preapical constriction; apex of internal sac pointed (Fig. 8G); female tergum X quadrate (Fig. 4E) D. germana (Sharp) (p. 97)


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Table 2. Known hosts of Dacnochilus species. Species

Hosts

D. angularis

Termites

D. basalis

Termes lespessi

D. bruchi

Solenopsis saevissima

D. bruchiana

Solenopsis saevissima

D. germana

Solenopsis saevissima, S. interrupta, S. richteri

D. laetus

Morph 1 Morph 2

D. pagana

Solenopsis geminata Simultaneous aggregations of ants and termites. Solenopsis interrupta, S. cf. saevissima, Pheidole sp. 1, and Pheidole sp. 2. Simultaneous aggregations of Solenopsis sp. and termites. Solenopsis sp.

D. huautlae, new species

Solenopsis geminata

D. rociae, new species

Solenopsis sp.

D. nigrapicalis, new species

Solenopsis xyloni

D. obscurior

SYSTEMATIC ENTOMOLOGY Order Coleoptera Linnaeus, 1758 Family Staphylinidae Latreille, 1802 Subfamily Paederinae Fleming, 1821 Tribe Paederini Fleming, 1821 Dacnochilus LeConte, 1861 Dacnochilus LeConte, 1861:66. Type species: Dacnochilus laetus LeConte, 1863 [Designated by subsequent monotypy]. Calophaena Lynch, 1884:267 (preoccupied name in Coleoptera, not Klug, 1821). Type species: Calophaena basalis Lynch, 1885 [Designated by monotypy]. Acalophaena Sharp, 1886:554 (new name for Calophaena Lynch, 1884). New synonym.

Distribution.—Species in the genus occur from the southern United States to northern Argentina (Figs. 13–16). Eleven species of Dacnochilus are known from North and Central America, and 15 species from South America. Diagnosis.—Dacnochilus is distinguished from other genera of Lathrobiina by a transverse pronotum almost as long as wide (subsquared or subrounded), head and pronotum with or without sparse puncturation on the disk, but with large black setae evident on edge of the disk. The labrum has a pair of teeth or at least acute projections at sides of median notch, or teeth absent with the sides of the median notch rounded (in D. laetus). In genera such as Lobrathium and Lathrobium, the pronotum is longer than wide, head and pronotum sparsely but obviously punctuate, and pronotal midline usually impunctate. Redescription.—Length 2–7.7mm. Head.—Triangular (Fig. 2A), 1.04–1.67X as wide as long; neck 1/3 to almost 1/4 as wide as head; surface smooth and shining, with sparse, fine or deep punctures. Sides of head, pronotum, and elytron with macrosetae 0.3 mm long or more. Eye 0.68 to 1.5X as long as temple or more. Gular

suture well developed and widely separated. Antenna gradually and slightly broader from base to apex (Figs. 2C, G), or filiform (Fig. 2H); antenna 0.64–1.2X as long as length of head and pronotum combined; first antennomere moderately flattened and 1.15–2.75X longer than second, its width 1.14–2.75X wider than base of second; third antennomere shorter to twice longer than second, more slender than remaining, except for the filiform antenna with antennomeres 3–11, equal in width; length of antennomeres 4–10 1.5X or more than twice its width, antennomeres 7–10 subrounded (Fig. 2C), subrectangular (Fig. 2G) or cylindrical, subparallel (Fig. 2H); antennomeres 1–3 with macrosetae, 4–11 with macrosetae and microsetae (Fig. 2C). Labrum with pair of teeth well developed (Fig. 2D, to), barely developed (Fig. 2I) or absent (Fig. 2J), and median notch broad. Mandible with well developed broad base with two (Fig. 2E) or more; than two teeth (Fig. 2B) , or base slender with one (Fig. 2F) or two teeth, apex slender, sharp pointed. Maxilla with four palpomeres (Fig. 2K) in some specimens slightly flattened; fourth palpomere without setae, conical and in some cases aciculate, small, in some specimens difficult to see; third palpomere slightly dilated (apex 2 or 3X wider than base) (Fig. 2K) or strongly dilated (apex 4 or 5X wider than base); stipes with few macrosetae; galea and lacinia with dense brush-like setae (Fig. 2K, ga, la). Labium with three palpomeres; third subparallel and without setae; second at least twice wider and longer than third, with very few macrosetae. Hypopharynx well developed (Fig. 2L, hp). Thorax.—Pronotum transverse (1.15–1.4X wider than long), subhexagonal (Fig. 3A), subrectangular (Figs. 3B–C) to very transverse (more than 1.4X wider than long) (Fig. 3D), or almost as long as wide (1–1.1X), subquadrate or subrounded (Fig. 3E); lateral margins straight (Fig. 3C), slightly to very convex (Figs. 3D–E) or concave (Fig. 3B) in dorsal view; surface smooth and shining, with scattered, sparse, fine or deep punctures denser on margins with macrosetae (Fig. 3A), punctures present or absent on central disk. Scutellum as in Fig. 3H with pair of punctures in middle. Elytron 0.93–1.5X as long as pronotum; elytral disk without punctures, or of one to three or more longitudinal rows of punctures slightly coarser than those of head and pronotum, distributed evenly (Fig. 3G); epipleura with rows of punctures; surface smooth and shining exclusively with macrosetae; hind margin of elytron with small setae forming fringe, variable in number; epipleural carina present (Fig. 3F) or absent. Hind wings typical of Staphylinidae, completely developed. Leg with four ctenidia parallel ordered and oblique on inner side of protibia (Fig. 3I). Apex of metatibia with ctenidium on both inner and outer side, setae of outer ctenidium longer (Fig. 3N). Tarsal formula 5-5-5 (Figs. 3J, L–M). Protarsomeres 1–4 bilobed (Fig. 3J), weakly bilobed or not bilobed, slightly broader in males than in females; protarsus 5 almost as long as 1–4 combined, with dense spatulate setae ventrally forming several locks (Fig. 3K).

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Fig. 4.—Abdominal segments of Dacnochilus. A–B, segment VIII of D. huautlae, new species, male: A, tergum; B, sternum. C–F, abdominal tergum X: C, D. ecuatoriensis, new species, male; D, D. rociae, new species, female; E, D. germana, female; F, D. obscurior, female. G, sternum IX and X of D. huautlae, new species, male; H, sternum IX of D. laetus, male. I–J, aedeagus of D. nahuiollinae, new species: I, dorsal view; J, lateral view. Abbreviations: asi, apex of internal sac; c, lateral sclerites of tergum IX; e, emargination; fo, foramen; lm, median lobe; pa, paramere; si, internal sac.

Mesotarsomeres (Fig. 3L) and metatarsomeres (Fig. 3M) cylindrical, length of tarsomeres 1–4 decreasing gradually from base to apex, 5 longer than 3 and 4 combined, covered with dense macrosetae ventrally. Legs with macrosetae. Abdomen.—Terga III–VII with or without basal, transverse tergal carina. Pattern of distribution of setae and puncturation on tergum variable. Tergum VIII apically rounded (Fig. 4A). Sternum VIII of males emarginate (Figs. 4B, 5A–Y), in females rounded. Lateral sclerites of tergum IX long, broad, or slender (Figs. 4G–H) and pointed. Sternum IX divided (Fig. 4G) or joined (Fig. 4H). Apex of tergum X sharp and projected like spine (Figs. 4C–E) or not projected (Fig. 4F). Aedeagus symmetrical in dorsal view (Figs. 4I, 6–8), with variable shape: oval, subparallel or subtriangular; paramere in lateral view concave, straight or sinuate, with or without preapical constriction; apex variable in shape: rounded, emarginate, truncate or pointed; apex of internal sac with simple lobe, bilobed, pointed, triangular with apex rounded, or M-shaped.

Biology.—The majority of the examined species of the genus occur in habitats at altitudes between sea level and

1300 m; however some species have been taken at 2000 m (D. macularis) and 2400 m (D. laetus). Dacnochilus germana and D. obscurior have the greatest altitude range, recorded from sea level to 3000 m. Most species have been attracted to light traps (black light or UV light and mercury vapor lamps) suggesting that species are nocturnal; less effective are flight intercept traps and malaise traps, but manual collection is very productive. The individuals are usually found under stones and logs, along streams, rivers, lagoons, damp areas, sand banks, and moist habitats near water reservoirs. Species of Dacnochilus occupy a wide range of habitats: tropical deciduous forest, rain forest, riparian forest, grasslands, marshes, and xeric shrubland. Nine of the 25 known species are evidently associated with ants, primarily with species of Solenopsis and less often with Pheidole. Others have been found in aggregations of

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Fig. 5.—Male abdominal sternum VIII of Dacnochilus. A, D. laetus; B, D. basalis; C, D. bruchi; D, D. nahuiollinae, new species; E, D. nigrapicalis, new species; F, D. compacta; G, D. zaragozae, new species; H, D. newtoni , new species; I, D. atrus, new species; J, D. horridula; K, D. megistothorax, new species; L, D. bruchiana; M, D. huautlae, new species; N, D. grandioculus, new species; O, D. angularis; P, D. bilobatus, new species; Q, D. obscurior; R, D. xilonenae, new species; S, D. polita; T, D. ecuatoriensis, new species; U, D. argentina; V, D. macularis; W, D. pagana; X, D. rociae, new species; Y, D. germana. Scale = 0.5 mm, valid for all figures.

ants and termites (D. laetus and D. obscurior), whereas other species have been collected exclusively as guests of termites (D. angularis and D. basalis)(Table 2). One specimen was collected in a mushroom. Dacnochilus angularis (Erichson, 1840), new combination (Figs. 5O, 7F, 10F, 13D) Lithocharis angularis Erichson, 1840:614. Acalophaena angularis (Erichson, 1840):614 [subsequent combination by Sharp (1886)]. Type Material.—LECTOTYPE (here designated): male labeled “Lith-

ocharis angularis Er. Type ex. Coll. Chevrolat Mexico” [mounting card] / “Type” [red label] / “Mexico” / “Sharp Coll. 1905.-313.” / “B. C. A. Col. I. 2. Acalophaena angularis, Er.” / “Lithocharis angularis Er. 614, 8 Mexico D. Salle” [folded green label] “Guadalupa” [on reverse side] / “Acalophaena angularis (Erichson, 1840) Lectotype des. E. JiménezSánchez 2006” (BMNH). PARALECTOTYPES (3 specimens): female, labeled: “Hist.-Coll. (Coleoptera) Nr. 6368 Lithocharis angularis Erichson, 1840 Nuev. Valenc. Moritz Zool. Mus. Berlin” / “Syntypus Lithocharis angularis Erichson, 1840 labelled by MNHUB 2006” [red label] / “Acalophaena angularis (Erichson, 1840) Paralectotype des. E. Jiménez-Sánchez 2006” / “Acalophaena germana (Sharp, 1876) det. E. Jiménez-Sánchez 2007” (MNHUB); male, labeled: “6368” / “angularis Er. Nov. Vol. Mor.” [green label] / “Syntypus Lithocharis angularis Erichson, 1840 labelled by MNHUB 2006” [red label] / “Acalophaena angularis (Erichson, 1840) Paralectotype des. E. Jiménez-Sánchez 2006” / “Acalophaena macularis

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(Erichson, 1840) det. E. Jiménez-Sánchez 2007” (MNHUB); female, labeled: “Hist.-Coll. (Coleoptera) Nr. 6368 Lithocharis angularis Erichson, 1840 Nuev. Valenc. Moritz Zool. Mus. Berlin” / “Syntypus Lithocharis angularis Erichson, 1840 labelled by MNHUB 2006” [red label] / “Acalophaena angularis (Erichson, 1840) Paralectotype des. E. Jiménez-Sánchez 2006” / “Acalophaena macularis (Erichson, 1840) det. E. JiménezSánchez 2007” (MNHUB).

Remarks.—The type series of Lithocharis angularis Erichson, 1840, is a mixture of species. The three syntype specimens from Colombia (MNHUB) and the specimen from Venezuela (BMNH) collected by Sallé and quoted by Sharp (1886) in the Biologia Centrali Americana, correspond to D. germana and D. macularis respectively. The specimen from Mexico (BMNH) is the only syntype conspecific with ones identified by authors as A. angularis. Erichson (1840) pointed out that D. macularis is related to D. angularis. Both species are similar in color, which might explain misidentification. We conclude that D. angularis was erroneously cited from Venezuela (Sharp 1886) and Colombia (Erichson 1840). A lectotype designation is mandatory in order to unambiguously delimit the name, therefore the only male syntype of L. angularis Erichson with features consistent with material from North and Central America was selected as lectotype. Distribution.—Dacnochilus angularis occurs from Texas, Gulf of Mexico coast, an isolated record in state of Querétaro, México, and Central America to Costa Rica (Fig. 13D). These are the first national records for the United States, Honduras, and Costa Rica. Diagnosis.—Differs from D. bilobatus, which is the most similar species, by the combination of black elytron except for reddish-brown hind outer angle, antennomeres 7–10 between 1.52–1.59X as long as greatest width, and elytron between 1.19–1.35X as long as pronotum. Male distinguished by the emargination of sternum VIII (Fig. 5O) and aedeagus (Fig. 7F). Redescription. Coloration.—Head black; pronotum reddish-brown; elytron black except hind outer angle reddish-brown; elytral suture black; abdomen reddish-brown; except first three-quarters of abdominal segment VII and apical half of VIII black (Fig. 10F); lateral sclerites of tergum IX black; antenna and palpus reddish-brown; legs yellowish-brown except for reddish-brown tibiae. Head of some specimens brown. Head, pronotum, and elytron dull due to poor preservation. Black mark on elytron covers only basal half or 3/4 parts and extends very little toward hind inner angle. Overall length of body 5.14 mm (±0.33, N=19, 4.5–5.8 mm). Head length + pronotum length + elytron length 2.77 mm (±0.19, N=19, 2.41–3 mm). Head.—Transverse, 1.36X (±0.08, N=18, range 1.2–1.55) wider than long and 1.04X (±0.05, N=19, range 0.96–1.22) wider than pronotum; epicranium with macrosetae and fine punctures, sparse on central disk, denser on fore and hind corners; eye as long as temple or longer 1.14 (±0.15, N=19, range 0.96–1.48), with few sparse, erect macrosetae along its margin; antenna gradually and slightly broader to apex, slightly longer 1.02 (±0.1, N=17, 0.88–1.22) than head and pronotum combined; first antennomere 1.99X (±0.37, N=18, range 1.47–2.6) as long as second and its widest 1.69X (±0.26, N=18, range 1.17–2) as wide as second; antennomere three 1.63X (±0.26, N=18, range 1–2) as long as second; articles 4–6 between 1.78–2.13X longer than greatest width and articles 7–10 between 1.52–1.59, subrounded. Labrum with pair of teeth well developed;

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mandible short, base wide with three or four teeth. Thorax.—Pronotum transverse 1.13X (±0.05, N=8, 1.07–1.2) wider than long, subpentagonal; lateral margin straight; central disk with longitudinal row of fine punctures bearing medium-sized setae on each side of midline, two rows on lateral side and lateral border with six–seven erect macrosetae; elytron 1.28X (±0.05, N=19, 1.19–1.35) as long as pronotum; central disk with four rows of fine punctures bearing macrosetae, one row near elytral suture; hind margin with approximately 10–12 minute setae forming a fringe; with epipleural carina in hind third; protarsus 1–4 bilobed. Abdomen.—Terga III–VII with or without carina basal and transverse; midline of terga III–VI with transverse row of