Oxyporus (Oxyporus) delgadoi Márquez, Asiain & Fierros­López, 2005

Márquez, Juan, Asiain, Julieta & Fierros-López, Hugo E., 2005, A new species of Oxyporus (Coleoptera: Staphylinidae: Oxyporinae) from Mexico, with notes on some poorly known species, Zootaxa 954, pp. 1-12 : 3-9

Oxyporus (Oxyporus) delgadoi Márquez, Asiain & Fierros­López , sp. nov. ( Figs. 1–5 )

Type material. Holotype, male: “ México: Hidalgo, Zacualtipán, Camino a Santo Domingo. Bosque mesófilo de montaña perturbado. 1830 m. N 20° 38´00.7”, W 98° 34´00.5”. En hongos Pholiota sp. 7­IX­2004. J. Márquez col./ Holotype Oxyporus delgadoi Márquez, Asiain & Fierros des. 2005” (CC­UAEH). Paratypes, six females: 2 ΨΨ, same data as holotype (CC­UAEH); 2 ΨΨ, same data as holotype, except: “ 9­VIII­2003. J. Asiain y J. Márquez cols.” (CC­UAEH); 2 ΨΨ, same data as previous specimens, except: “H. Fierros­López col.” (1, CZUG; 1, JLN).

Description. Total body length 9.6­11.5 mm. Head black; palpi, antennae, gular area, and neck red. Thorax, including legs and most of the elytra, red; posterior 1/5 of elytra black. Visible abdominal segments 1, 2, 6 and genital segment red; segment 3 with anterior 1/3 red and posterior 2/3 black, forming black trapezoid on tergite 3; segments 4 and 5

black, except posterior margin of segment 5 which is red.

Head. Length 1.65­2.20 mm; width behind eyes 1.9­2.5 mm. Shape slightly transverse, with lateral margins rounded. Dorsal surface near even, with sparse fine punctures. Frons behind supra­antennal carinae sunken, with small central depression behind the sunken area. With one seta near anterior margin of each eye, and one seta near posterior margin. Eyes length 0.65­0.85 mm. Antennae 0.9 times as long as head; antennomeres 1­4 elongate, second slightly shorter and wider than third, fifth slightly elongate and conic shaped, 6­10 transverse, slightly asymmetrical and flattened, apical antennomere conic and less wide than apex of previous antennomere; all antennomeres with long setae near apex, antennomeres 5­10 with their axial part glabrous and lateral parts covered with fine setae. Clypeus narrows anteriad. Labrum strongly narrows anteriad, with few long setae along midline and with brush of yellow setae at anterior margin. Mandible length 1.4­1.9 mm; with lateral channel at 2/3 of their length; ventral surface of right mandible with small external tooth; ventral surface of left mandible with two acute teeth: the external slightly longer than the internal. Maxillary palps with first segment shortest, second longer than third, third longer than fourth, which is slightly acute and flattened apically. Apical segment of labial palps as wide as length of eye; mentum long, with longitudinal carinate line in posterior half and with lateral borders straight. Ventral surface of head even. Gular sutures separated ( Fig. 3 ). Neck with net­like microsculpture.

Thorax. Pronotum length 1.60­1.99 mm; maximum width at anterior third 1.7­2.2 mm. Pronotum with curved lateral sides; anterior margin narrows; with two punctures on each lateral margin; with posterior margin straight and marginal border slightly carinate. Scutellum short, with apex rounded. Length of elytra 2.25­2.96 mm (humeral to posterior margin); width at humeral level 2.3­2.8 mm, width at posterior angles 3.0­ 3.3 mm. Each elytron with two close longitudinal rows of approximately ten punctures each, external row with the anterior puncture near anterior margin of elytron and the posterior puncture before black apical portion of elytron; internal row with the posterior puncture close to posterior margin of elytron and the anterior puncture at distance of 1/3 elytron length from anterior margin. All margins of elytron with several short setae. Metasternum with sparse yellow setae.

Legs. Pro­ and metatibiae with fewer spines at external margin, compared with mesotibiae. Tarsi with apical tarsomere as long as first four tarsomeres together, second slightly longer than first, third shorter than previous and fourth the shortest.

Abdomen. Tergites with net­like microsculpture. Five first visible tergites with anterolateral curved impression and single short seta near each posterior corner. All sternites with yellow setae at posterior margin, on posterior sternites these setae are denser and longer.

Aedeagus. Length 1.375 mm; median lobe elongate in lateral view, in ventral view subapical portion wider than middle portion, its apex pointed and asymmetrical; parameres slender, 0.2 times as long as median lobe; internal sac with acute internal sclerite, with spines proximally of the internal sclerite and scale­like spinules proximally of the spines ( Fig. 4 ).

Diagnosis. Oxyporus delgadoi differs from all Mexican species of Oxyporus in having a unique body color: the head is black; the pronotum is red; the abdomen is red except in the posterior half of third visible segment, the entire fourth and the main part of the fifth segment. In O. delgadoi the elytra have two longitudinal rows of approximately ten punctures; the aedeagus is long, with the apex of the median lobe acute and asymmetrical.

Of all Mexican species of Oxyporus , O. delgadoi is most similar to O. flohri . The two species can be distinguished as follows: in O. flohri the red color of the body is not as intense as in O. delgadoi ; in O. flohri the head and pronotum are piceous with some variable black spots, whereas in O. delgadoi the head is black (with only two red spots) and the pronotum is red; in O. flohri the fourth, or both the third and the fourth visible abdominal segments are black, while in O. delgadoi a part of the third, the entire fourth and a major part of the fifth visible abdominal segment are black ( Figs. 1–2 ).

Variation. The female paratypes are larger (10.8­11.5 mm) than the male holotype (9.6 mm). There is also some variation in the body color ( Fig. 5 ): the female paratypes have two red spots on the head disk, these spots are small in some specimens and large in others; in some females the red color of the neck extends irregularly to the posterior portion of the head disk; the base of the mandibles may be red; the black posterior portion of the elytra may be wider or less wide than in the holotype; the black portion of the third visible abdominal tergite may be restricted to its posterior margin or be trapezoid as in the holotype; the extent of the red portion of the fifth visible abdominal tergite varies from a narrow posterior margin (as in the holotype) to a half of the tergite ( Fig. 5 ).

Remarks and discussion. Oxyporus delgadoi presents the characteristics of the subgenus Oxyporus s. str. ( Nakane & Sawada 1956; Campbell 1969). However, the aedeagus of the new species is asymmetrical ( Fig. 4 ), as in the three North American species of the subgenus Pseudoxyporus : Oxyporus (P.) lateralis Gravenhorst, 1802 , O. (P.) occipitalis Fauvel, 1864 and O. (P.) quinquemaculatus LeConte, 1863 . Oxyporus smithi was considered by Campbell (1969) as a member of Pseudoxyporus , but recently this species was moved to Oxyporus s. str. ( Navarrete­Heredia et al. 2002).

In many species of Oxyporus the body color is known to be highly variable (e. g., in Oxyporus vittatus Gravenhorst, 1802 ; see Campbell 1969); however, the new species presents a color pattern very different from any other New World species.

To accommodate the new species, the key to Mexican species of Oxyporus proposed by Navarrete­Heredia and Novelo­Gutiérrez (1990) can be modified as follows:

5. Abdomen orange, completely lacking black markings; head, prothorax, outer apical angles of elytra, procoxae and mesepisterna black; surface of head and pronotum very finely granulate, glossy; length 6.5–10.3 mm .......................... O. lawrencei Campbell 5´. Color not as above ........................................................................................................ 6 6. Head and pronotum yellow or piceus, with some variable black spots; abdomen with only fourth, or third and fourth visible abdominal segments black; length 8.8 mm ...... ................................................................................................................ O. flohri Sharp

6´. Head black, with two red spots between eyes; pronotum red; abdomen with posterior half of third, entire fourth and major part of fifth visible abdominal segments black ( Figs. 1–2 , 5 ); length 9.6–11.5 mm ............................................... O. delgadoi , sp. nov.

Bionomics. Oxyporus delgadoi was collected on mushrooms of an unidentified species of the genus Pholiota . In 2003, we collected the first four female specimens on mushrooms associated with a decaying log near a road. The specimens were found in the galleries they excavated in the mushroom pileus. The absence of males may indicate that the females were ovipositing and/or providing parental care. When disturbed, the females tried to escape and we did not have an opportunity to observe their behavior. We tried to collect more specimens, particularly males, for several days searching additional mushrooms ( Pholiota and others). We also installed temporal traps baited with local mushrooms, but all our attempts were futile. In 2004, the first author visited the same decaying log where the first specimens had been found and collected three more specimens, one of them a male. Again, extended search for additional specimens on other mushrooms and use of a flight intercept trap produced no results. Thus, the new species has been collected only on mushrooms of the genus Pholiota and only on one decaying log. Therefore we conclude that in its type locality Oxyporus delgadoi may be a rare species, possibly because the host mushroom species may also be rare. Hanley and Goodrich (1995) described five patterns of host selection in Oxyporus . The new species is tentatively assigned to pattern 5: adult host selection is specific to one species of mushroom. As accompanying fauna, several specimens of Erotylidae were collected on the same Pholiota mushroom.

Etymology. We dedicate this species to Luis Leonardo Delgado Castillo (Instituto de Ecología, Asociación Civil), in recognition of his extensive contribution to the study of Mexican scarabs and his collection of staphylinids loaned to us for study on several occasions.

Figures

FIGURE 1. Habitus drawing of Oxyporus delgadoi (holotype), dorsal view. Scale bar 1 mm.

FIGURE 2. Photo of Oxyporus delgadoi (paratype), dorsal view. Scale bar 1 mm.

FIGURE 3. Head of Oxyporus delgadoi, ventral view, showing the gular sutures. Scale bar 1 mm.

FIGURE 4. Aedeagus of Oxyporus delgadoi (holotype): a) ventral view, b) lateral view, c) detail of the internal sac. Scale bar 0.4 mm.

FIGURE 5. Variation in color pattern and size in six female paratypes of Oxyporus delgadoi. White color in the drawings indicates red color in the specimens. Scale bar 1 mm.