NAMERICAN MUSEUM Novttates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET NEW YORK, N.Y. 10024 U.S.A. NUMBER 2683 SEPTEMBER 9, 1979 LE H. HRMAN Revision of Stereocephalus (Coleoptera, Staphylinidae, Paederinae) f. AMERICAN MUSEUM Novitates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2683, pp. 1-13, figs. 1-47 September 9, 1979 Revision of Stereocephalus (Coleoptera, Staphylinidae, Paederinae) LEE H. HERMAN' ABSTRACT Stereocephalus, which occurs east of the Andes redescribed and S. dilaticeps Bernhauer is placed as from Venezuela to northern Argentina, is transferred a junior synonym of seriatipennis. A key and illus- from one paederine subtribe, the Dolicaonina, to trations are provided. Stereocephalus seriatipennis another, the Lathrobiina. Three new species, S. my- and S. rinnanus are sister species and together with rigeus, S. ruhus, and S. rinnanus, all from Brazil, S. ruhus comprise the sister group of S. myrigeus. are described. Stereocephalus seriatipennis Lynch is INTRODUCTION Upon beginning my revision of the Argentina. Later, Bemhauer (1939) added a paederine subtribe Dolicaonina it was imme- second species, dilaticeps, from Argentina and diately apparent that one of the included gen- Paraguay. era, Stereocephalus, should be removed When Stereocephalus was described it was because it lacks a short, broad, pubescent, regarded as near Dolicaon (Lynch, 1884, p. compressed fourth segment of the maxillary 233), although no reasons were given for so palpus and an enlarged, sclerotized, meso- believing. Blackwelder (1944, p. 126), follow- thoracic spiracular peritreme, both features ap- ing Lynch, listed Stereocephalus and Dolicaon omorphic for the subtribe. The broad, in the subtribe Dolicaoni (= Dolicaonina). compressed fourth segment of the maxillary However, in a paper devoted to African palpus of Stereocephalus is glabrous and the Paederini, Fagel (1958) briefly discussed Ste- mesothoracic spiracular peritreme is small. The reocephalus and several other neotropical gen- following pages will specify characters for a era that possess a compressed fourth segment new subtribal assignment, propose a phylogeny of the maxillary palpus, a character which he of the species, describe three new species, and used to help distinguish the Paederini from the place into synonymy one species. Lathrobiini. He concluded that Stereocephalus Stereocephalus is a South American genus should be moved near the Lathrobiini because first described by Lynch (1884) and in which of unspecified characters of the labrum, anten- he included one species, seriatipennis, from nae, legs, and aedeagus. 'Curator, Departnent of Entomology, American Museum of Natural History. Copyright ( American Museum of Natural History 1979 ISSN 0003-0082 / Price $1.15 2 AMERICAN MUSEUM NOVITATES NO. 2683 The classification of the subtribes of the seum of Comparative Zoology, Harvard Uni- Paederinae is poorly developed in that it lacks versity, Cambridge; for the Scanning Electron well-defined taxa, does not explicitly attempt Micrographs: Mr. Robert Koestler, American use of shared, derived features, and does not Museum of Natural History; and for reviewing include many described genera (see Casey, the manuscript; Mr. Larry Watrous, Ohio State 1905; Bordoni, 1975; Ganglbauer, 1895). It is University, Columbus, and Dr. Alfred Newton. often difficult to assign genera to subtribes with confidence. STEREOCEPHALUS LYNCH Pending further study of the subtribal classi- fication, I suggest Stereocephalus Lynch, 1884, p. 231. Blackwelder, including Stereocephalus in 1944, 126. 7. the subtribe Lathrobiina. Stereocephalus shares p. Fagel, 1958, p. with members of this subtribe the bilobed, TYPE SPECIES: Stereocephalus seriatipennis edentate labrum (figs. 2, 6, 45), the expanded, Lynch, by monotypy. basal four protarsomeres (fig. 2), and the DIAGNOSIS: This genus can be separated aedeagal parameres (figs. 11, 12, 24, 26) that from all other Paederinae by the lamina-like, are short and tightly appressed to the median broad, flattened, glabrous fourth segment of the lobe, all of which appear to be derived for and maxillary palpus (figs. 3, 22, 23). Further dis- unique to the subtribe. tinctive features are the deep, U-shaped labral Bordoni (1975) stated that Lathrobiini (and emargination (figs. 2, 6, 45), the dense puncta- therefore Lathrobiina) lack parameres. I inter- tion of the head, pronotum, and elytra (figs. 2, pret the flat lobes appressed to the base of the 32, 38, 45), the modestly developed furcaster- median lobe just laterad of the basal orifice to num (fig. 17), the small mesothoracic spiracu- be reduced parameres (figs. 11, 12, 24, 26, 44, lar peritreme, and the invagination of the apex 46). These short, flat parameres are found in at of the aedeagus (figs. 12, 24, 36, 46). least some species of Lathrobium, Lobrathium, DESCRIPrION: Length 4 to 14 mm. Color Domene, and Dachnochilus. In Achenium de- reddish brown. Body without trichobothria. pressum they are long and slender but originate Head with dense, umbilicate punctation; at the same point near the basal orifice. shape quadranguloid with well-developed basal Stereocephalus is monophlyetic as defined angles; nuchal margin broadly emarginate (figs. by the compressed, lamina-like, fourth segment 2, 32). Gular sutures most approximate near of the maxillary palpus (figs. 3, 22, 23) and by middle. Neck width more than one-half width the invagination of the apex of the median lobe of head; ventral surface with deep depression (figs. 12, 24, 36, 46), both of which are fea- on each side of triangular elevation. Labrum tures unique to the genus. Comparison with with deep, broad, median emargination (figs. 2, other Lathrobiina suggests that seriatipennis 6, 45). Maxillary palpus with third segment and rinnanus are sister species that share the broad and flattened (figs. 3, 22); fourth seg- unique autapomorphous, transverse, glabrous ment broad, compressed, laminalike, and with- spots on the dorsum of the head. These two out pubescence (figs. 22, 23). Labium with species together with ruhus have uniquely simi- second palpal segment flattened, stout, and lar struts on the internal sac (figs. 13, 14, 27, longer than first or third segment (fig. 1); sub- 30, 39, 40), and form the sister group of myri- mentum transverse and trapezoidal; hypo- geus. pharynx with four lobes on anterior margin, median lobe rounded, lateral lobe long and ACKNOWLEDGMENTS acute and with row of setae extending from apex to base and converging toward middle I thank the following for lending specimens: (fig. 21). Mandibles short and broad (figs. 4, Dr. Milton Campbell, Canadian National Col- 5). Antenna with basal article stout and bent lection, Ottawa; Mr. Henry Dybas, Field Mu- laterally (fig. 7). seum of Natural History, Chicago; Dr. Terry Prothorax slightly longer than wide (fig. 2); Erwin, National Museum of Natural History, furcasternum long, moderately wide, tapered Washington, D. C.; Dr. Alfred Newton, Mu- apically, and with well-developed median cari- 3 F FIGS. 1-7. Stereocephalus seriatipennis. 1. Labial palps. 2. Habitus. 3. Maxillary palpus. 4. Left mandible. 5. Right mandible. 6. Labrum. 7. Antennomeres 1 and 2. 4 AMERICAN MUSEUM NOVITATES NO. 2683 na (fig. 17). Mesothoracic spiracular peritreme rounded lobe on posterior margin (fig. 43); small. Elytral epipleural ridge absent. Meso- ventral sclerite of aedeagus with two long, sternum (fig. 8) without median fovea but with slender, prongs on apical portion (fig. 42); broad, median depression; sternopleural ridge Brazil ...... myrigeus present; anterior portion with shallow depres- Sternite VII with obsolete median lobe on pos- sion on each side of midline. terior margin or with truncate posterior Mesosternal-me- margin; ventral sclerite of aedeagus with tasternal suture present. apical portion variously modified (figs. 15, Protarsus (fig. 2) with first four articles ex- 16, 25, 37) ...... 3 panded and with dense pubescence beneath. 3(2). Dorsum of head with dense, reticulate puncta- Metatibia with ctenidium on each side of apex. tion and without median glabrous spots Abdominal segments III to VII each with (fig. 38); ventral sclerite of aedeagus with two pairs of parasclerites (fig. 2). Sternite IV apical portion undivided and attenuate (fig. without glandular opening at middle of anterior 37); Brazil ...... ruhus margin. Tergum IX fused medially (figs. 9, Dorsum of head densely punctate and with 28); lateroapical processes long, slender, and two, transverse, polished, median spots with apex dorsally curved. (figs. 2, 32); ventral sclerite of aedeagus with apical margin emarginate (figs. 15, Male. Genital sclerite (sternum IX) elongate 16, 25) ...... 4 and with apical margin shallowly emarginate 4(3). Abdominal surface shining dully, with strong (fig. 29). ground sculpturing between punctures; Aedeagus trilobed. Parameres (figs. 11, 12, aedeagus, in dorsal view, with sinuotrun- 24, 26, 44) reduced to short, flattened lobes cate apical margin (fig. 26); ventral sclerite near basal foramen and without setae. Median of aedeagus with deep broad emargination lobe long, tapered apically, with broad plate of apical margin (fig. 25); Brazil ....... behind basal foramen (figs. 11, 26); ventral .............................rinnanus surface with midlongitudinal region mem- Abdominal surface polished, without ground branous; apical portion of ventral surface sculpturing between punctures; aedeagus,