Isanopus sahlbergi Bernhauer, 1917

Chatzimanolis, Stylianos, 2008, A revision of the neotropical beetle genus Isanopus Sharp, 1876 (Coleoptera: Staphylinidae: Staphylinini), Journal of Natural History 42 (25 - 26), pp. 1765-1792 : 1781-1790

Isanopus sahlbergi Bernhauer, 1917

( Figure 2B )

Isanopus sahlbergi Bernhauer, 1917, p. 109 .

Diagnosis

Isanopus sahlbergi can be distinguished from all other known Isanopus species by the shape of the antennomeres. In I. sahlbergi the antennomeres are much shorter than any other species and it can only be mistaken for I. eptaskouros ; however the two species can easily be distinguished by the colouration of abdominal segment VII which is completely dark brown-black in I. eptaskouros .

Description

Length 9.5 mm.

Colouration. Colour of head and pronotum dark brown to black. Antenna brown. Scutellum dark brown to black. Elytra dark metallic greenish blue. Abdomen dark brown, except segment VII anterior 1/5 brown, posterior 4/5 yellow, and segments VIII–IX yellow. Legs brown except tarsi light brown.

Head. Head with many relatively small brown microsetae and longer black macrosetae along borders of head; head subquadrate, width: length ratio51.16. Surface of epicranium glossy, with few micropunctures distributed at centre. Epicranium slightly convex, with small-sized umbilicate setose punctures laterally, no punctures medially, setose punctures irregularly arranged in 1–2 rows anteriorposteriorly, punctures smaller around eyes and at base of head, distance between punctures various, from 0.5–1 times width of punctures, but punctures at base of head almost confluent. Eyes medium, length of eyes/length of head50.57, distance between eyes as wide as 1.5 times length of eye. Postgena with medium, longitudinally elongate punctures (about six punctures/ 0.5 mm), punctures not uniformly distributed. Antennomeres with long macrosetae, antennomere 1 gradually club-like thickened, antennomeres 1–10 longer than wide, antennomere 1 about twice as long as antennomere 2, antennomere 3 about 1.5 times as long as antennomere 2, antennomere 4 0.7 times shorter than antennomere 3, antennomeres 5–10 almost identical, 1.6 times longer than wide, antennomere 11 subequal to previous antennomeres. Neck with multiple micropunctures but without other punctures. Thorax: Pronotum slightly longer than wide, width: length ratio50.91; antero-lateral angles obtusely rounded, slightly curved. Lateral margins of pronotum concave in dorsal aspect, pronotum broadest in apical 1/2 and narrower at basal angles. Surface of pronotum flat, glossy, with few micropunctures. Setose punctures absent on disc of pronotum, laterally present in 4–5 rows, distance between rows smaller towards lateral ends; punctures of medium size (about five punctures/ 0.5 mm); least distance between punctures for each row various, 1–2 times width of puncture for most; antero-lateral angles densely punctuated, distance between punctures 0.5–1 times width of puncture. Pronotum with brown microsetae directed postero-medially in lateral and anterior areas and posteriorly in basal half; and few longer black macrosetae along borders. Scutellum prominent, with brown microsetae and dense punctures, punctures confluent. Elytra subequal in length to pronotum, with medium setose uniform punctures (about seven punctures/ 0.5 mm), covered with yellowish brown microsetae and longer black macrosetae along borders of elytra.

Legs. Protarsus missing; meso and metatarsi slightly elongate and enlarged, tarsomeres 1–4 dilated distally. Legs almost completely covered with long yellow and brown setae.

Abdomen. Abdominal terga III–V with tergal basal and no subbasal (arch-like) carina. Terga III–VII with uniform punctuation patterns, densely covered with punctures and yellowish brown setae, punctures not decreasing in size gradually from III–VII. Abdominal sterna III–IV with moderate transverse impressions, V with faint transverse impression, shining. Integument surface appearing strongly iridescent in strong direct light at moderate to high magnification. Sterna III–VII densely punctuated, punctures not decreasing in size gradually from III–VII, with yellowish brown setae. Lateral tergal sclerites of the abdominal segment IX long and straight, covered with long black macrosetae.

Secondary sexual structures. Male: unknown. Females: with no obvious sexual structures.

Aedeagus. Males not known.

Lectotype: here designated, female, head and thorax on card, rest of the body pinned, and with labels as follows: ‘‘ Isanopus sahlbergi Brnh Typus’’/‘‘Brazilien, Petropolis, iii.[1]850, Sahlberg’’/‘‘Chicago NHMuseum, M. Bernhauer collection’’/ ‘‘ Lectotype Isanopus sahlbergi Bernhauer design. Chatzimanolis 2007’’. In the collection of the Field Museum of Natural History, Chicago.

Remarks. Bernhauer (1917) stated that the specimens (presumably two) were deposited in his collection and in the collection of the Natural History Museum in Helsinki (Helsingfors). However, no specimens of Isanopus are present in the collection of the Natural History Museum in Helsinki, and the syntype is presumed lost (Dr. Hans Silfverberg pers. comm.). Therefore, the single specimen from the type series left is designated as the lectotype.

Distribution. Known from Boa Sorta, Petropolis, Brazil. ( Figure 11 ).

Habitat. Unknown.

Isanopus sallaei Sharp, 1884

( Figures 1B , 4B, 8A–C)

Isanopus sallaei Sharp, 1884, p. 360 .

Diagnosis

Isanopus sallaei and I. tenuicornis are the only species in Isanopus where the pronotum appears convex in lateral view and basally constricted in dorsal view ( Figures 1A, B ). Besides the differences in geographical distribution ( I. sallaei occurs in Central America, I. tenuicornis in South America), in I. tenuicornis the head is

densely punctuated (compare Figures 1A and B ) and both species have distinctive aedeagi ( Figures 8 A–C and 9A–C).

Description

Length 12.5–13.4 mm.

Colouration. Colour of head and pronotum dark brown to black. Antenna yellow, except colour of antennomeres 1–3, dark yellow to brown. Scutellum dark brown to black. Elytra dark metallic blue, or purplish blue. Abdomen with dark brown to black, except segments VII–IX yellow. Legs dark brown except tarsi light brown.

Head. Head with relatively small brown microsetae and longer black macrosetae along borders of head; head slightly transverse, width: length ratio51.20. Surface of epicranium glossy, with very few micropunctures distributed at centre. Epicranium flat, with sparse medium-sized umbilicate setose punctures laterally, no punctures medially, setose punctures irregularly arranged in 3–4 rows anterior-posteriorly, punctures smaller around eyes, distance between punctures various, from 1–2 times width of punctures. Eyes medium, length of eyes/length of head50.48, distance between eyes as wide as 1.65 times length of eye. Postgena with large, longitudinally elongate punctures (about 2–3 punctures/ 0.5 mm), punctures not uniformly distributed. Antennomeres with long macrosetae, antennomere 1 gradually clublike thickened, antennomeres 1–11 longer than wide, antennomere 1 about twice as long as antennomere 2, antennomere 3 1.5 times longer than antennomere 2, antennomere 4 slightly shorter than antennomere 3, antennomeres 5–10 almost identical, 2.5 times longer than wide, antennomere 11 subequal to previous antennomeres. Neck dorsally with no punctures or micropunctures, laterally with 3– 4 small punctures

Thorax. Pronotum longer than wide, width: length ratio50.81; antero-lateral angles obtusely rounded, curved. Lateral margins of pronotum concave in dorsal aspect, pronotum broadest in apical 1/4 and narrower at basal angles. Surface of pronotum slightly convex; glossy, with no micropunctures. Setose punctures absent on disc of pronotum, laterally present in 3–4 rows, distance between rows smaller towards lateral ends; punctures of medium size (about four punctures/ 0.5 mm); least distance between punctures for each row various, 1.5–3 times width of puncture for most. Pronotum with brown microsetae directed postero-medially in lateral and anterior areas and posteriorly in basal half; and few longer black macrosetae along borders. Scutellum prominent, with brown microsetae and sparse punctures, least distance between punctures 1–1.5 times width of puncture.

Elytra subequal in length to pronotum, with medium setose uniform punctures (about seven punctures/ 0.5 mm), covered with yellowish brown microsetae and longer black macrosetae along borders of elytra.

Legs. Protarsus enlarged; meso and metatarsi elongate and enlarged, tarsomeres 1–4 asymmetrical, dilated distally. Legs almost completely covered with long yellow and brown setae.

Abdomen. Abdominal terga III–V with tergal basal and no subbasal (arch-like) carina. Terga III–VII with uniform punctuation patterns, densely covered with punctures and yellowish brown setae, punctures decreasing in size gradually from III–VII. Abdominal sterna III–IV with moderate transverse impressions, V with faint transverse impression, shining. Integument surface appearing slightly iridescent in strong direct light at moderate to high magnification. Sterna III–VII densely punctuated, punctures decreasing in size gradually from III–VII, with yellowish brown setae. Lateral tergal sclerites of the abdominal segment IX long and straight, covered with long black macrosetae.

Secondary sexual structures. Male: distal margin of sternum VII with slight emargination medially; sternum VIII with deep V-shaped emargination medially; sternum IX with small emargination medially. Females: with no obvious sexual structures.

Aedeagus. As in Figures 8 A–C; paramere extremely reduced; paramere: median lobe ratio50.34. Paramere in dorsal view fairly wide but converging to two apical processes, with narrow U-shaped emargination between them; in lateral outline almost straight; with no apparent sensory spinules. Median lobe in dorsal view wide, converging to apex; in lateral view becoming narrower and strongly curved from middle to apex.

Holotype. Male, on card with D. Sharp’s handwriting ‘‘ Isanopus sallaei . „ Type D. S. Cordova. Mexico. Salle´’’, and with labels as follows: ‘‘Holotype’’/‘‘Cordova’’/ ‘‘ Mexico Salle Coll.’’/‘‘B.C.A. Col. I. 2. Isanopus sallaei , Sharp’’/‘‘ Holotype Isanopus sallaei Sharp det. R. G. Booth’’. The correct current name for the type locality is Córdoba, in the state of Veracruz, Mexico. In the collection of the Natural History Museum, London. Sharp (1884) specifically states in the original description that he had available only a single male specimen; that specimen is therefore the holotype for the species.

Additional material. HONDURAS: Atlantida Lancetilla Bot. Gard., Tela , 10 m, vi- 22-1994, 15 ° 469N 87 ° 279 W, J. Asheand R . Brooks , ex: treefall litter (1 in SEMC) ; MEXICO: Guerrero, 63km NE Atoyac de Alvarez , vii-24-1992, 1700 m, J.S. Ashe, ex: treefall litter (I in SEMC) ; 5 mi. SW El Bosque, Chris. vii-4-1969, CampbellandBright (1 in CNCI) .

Distribution. Known from elevations of 10 to 1700 m, Honduras and Mexico (Figure 32).

Habitat. Collected in treefall litter.

Isanopus tenuicornis Sharp, 1876

( Figures 1A , 4D, 9A–C)

Isanopus tenuicornis Sharp, 1876, p. 141 .

Diagnosis

Isanopus tenuicornis and I. sallaei are the only species in Isanopus where the pronotum appears convex in lateral view and basally constricted in dorsal view ( Figure 1 ). Besides the differences in geographical distribution ( I. tenuicornis occurs in South America, I. sallaei in Central America), in I. tenuicornis the head is densely

punctuated (compare Figures 1A and B ) and both species have distinctive aedeagi ( Figures 8 A–C, 9A–C).

Description

Length 12–13.4 mm.

Colouration. Colour of head and pronotum dark brown to black. Antenna yellow, except colour of antennomeres 1–3, brown. Scutellum dark brown to black. Elytra dark metallic blue, purplish blue, sometimes with green overtones. Abdomen dark brown, except segment VII anterior half brown, posterior half yellow, and segments VIII–IX yellow. Legs dark brown except tarsi light brown.

Head. Head with many relatively small brown microsetae and longer black macrosetae along borders of head; head subquadrate, width: length ratio51.16. Surface of epicranium glossy, with few micropunctures distributed at centre. Epicranium strongly convex, with small sized umbilicate setose punctures laterally, no punctures medially, setose punctures irregularly arranged in 4–5 rows anteriorposteriorly, punctures smaller around eyes and at base of head, distance between punctures various, from 0.5–1 times width of punctures at the centre, but punctures at posterior half of head almost confluent. Eyes medium, length of eyes/length of head50.51, distance between eyes as wide as 1.7 times length of eye. Postgena with medium, longitudinally elongate punctures (about six punctures/ 0.5 mm), punctures not uniformly distributed. Antennomeres with long macrosetae, antennomere 1 gradually club-like thickened, antennomeres 1–11 longer than wide, antennomere 1 about twice as long as antennomere 2, antennomere 3 about twice as long as antennomere 2, antennomere 4 slightly shorter than antennomere 3, antennomeres 5–10 almost identical, 3 times longer than wide, antennomere 11 subequal to previous antennomeres. Neck with multiple small irregular punctures and micropunctures.

Thorax. Pronotum longer than wide, width: length ratio50.77; antero-lateral angles obtusely rounded, slightly curved. Lateral margins of pronotum concave in dorsal aspect, pronotum broadest in apical 1/3 and narrower at basal angles. Surface of pronotum strongly convex; glossy, with few micropunctures. Setose punctures absent on disc of pronotum, laterally present in 4–5 rows, distance between rows smaller towards lateral ends; punctures of medium size (about five punctures/ 0.5 mm); least distance between punctures for each row various, 1–2 times width of puncture for most; antero-lateral angles densely punctuated, distance between punctures 0.5–1 times width of puncture. Pronotum with brown microsetae directed postero-medially in lateral and anterior areas and posteriorly in basal half; and few longer black macrosetae along borders. Scutellum prominent, with brown microsetae and dense punctures, punctures confluent. Elytra subequal in length to pronotum, with medium setose uniform punctures (about seven punctures/ 0.5 mm), covered with yellowish brown microsetae and longer black macrosetae along borders of elytra.

Legs. Protarsus enlarged; meso and metatarsi elongate and enlarged, tarsomeres 1–4 asymmetrical, dilated distally. Legs almost completely covered with long yellow and brown setae.

Abdomen. Abdominal terga III–V with tergal basal and no subbasal (arch-like) carina. Terga III–VII with uniform punctuation patterns, densely covered with punctures and yellowish brown setae, punctures not decreasing in size gradually from III–VII. Abdominal sterna III–IV with moderate transverse impressions, V with faint transverse impression, shining. Integument surface appearing strongly iridescent in strong direct light at moderate to high magnification. Sterna III–VII densely punctuated, punctures not decreasing in size gradually from III–VII, with yellowish brown setae. Lateral tergal sclerites of the abdominal segment IX long and straight, covered with long black macrosetae.

Secondary sexual structures. Male: distal margin of sternum VII with slight emargination medially; sternum VIII with deep V-shaped emargination medially; sternum IX with small emargination medially. Females: with no obvious sexual structures.

Aedeagus. As in Figures 9 A–C; paramere extremely reduced; paramere: median lobe ratio50.42. Paramere in dorsal view almost parallel-sided with no apical processes; in lateral outline almost straight; with two small patches of sensory spinules apically. Median lobe in dorsal view constricted to a narrower apical lobe;

in lateral view becoming narrower from apically, apex with a small ventral tooth, rounded.

Holotype. Female, on card with dissected IX sternum, and with labels as follows: ‘‘Type’’/‘‘Ega’’/‘‘S. America: Brazil’’/‘‘Sharp coll. 1905-313’’/‘‘ Isanopus tenuicornis ♀, Type, D. S.’’ In the collection of the Natural History Museum, London. Sharp (1876) specifically states in the original description that he had available only a single female specimen; that specimen is therefore the holotype for the species.

Additional material. BOLIVIA: Cochabamba, Cochabamba, 117 km E Yungas ( Cochabamba-Villa Tunari Rd. ), 1040 m, 17 ° 69320S, 65 ° 419120W, ii.1–6.1999, R . Hanley , ex: flight intercept trap (1 in SEMC) ; Santa Cruz Dept. , 3.7 km SSE Buena Vista Hotel Flora Y Fauna, 17 ° 29.959S, 63 ° 33.159W, 400–440 m, xi.3–9.2002, primary forest, FIT, R . Leschen (1 in SEMC) ; ECUADOR: Napo Prov., Limoncocha , 250 m, vi.15–28.[19]76, S. and J. Peck (1 in CNC) ; PERU: Junín Dept. , La Merced, 9.5 km NE La Merced-Villa Rica Rd., 880 m, 10 ° 589420S, 75 ° 189180W, x.15–21.1999, R . Brooks , ex: flight intercept trap (2 in SEMC). Additionally, there is one more specimen in FMNH (Bernhauer Coll.) with no locality data.

Distribution. Known from elevations of 220 to 1040 m in Bolivia, Brazil, Ecuador, and Peru ( Figure 11 ).

Habitat. Unknown, collected in flight intercept traps.

Key to the species of Isanopus

Males of Isanopus can be easily identified by their distinctive aedeagi, except in I. sahlbergi where no males are known yet. The following key, however, does not rely exclusively on male characters, and it can be also used for the identification of females.

1. Head punctuation on the posterior part of the head almost confluent ( Figures 1A , 2B, 2D )..................................... 2

– Head punctuation on the posterior part of the head less dense, distance between punctures at least 0.5–1 size of puncture ( Figures 1B , 2A, 2C ).. 4

2. Abdominal segment VII completely dark brown to black, aedeagus as in Figures 6 A–C................................. I. eptaskouros

– Abdominal segment VII orange or combination of dark brown and orange, aedeagus not as above.................................... 3

3. Antennomeres 5–10 almost identical, elongate, at least 2.5 times longer than wide (Figure 4D), aedeagus as in Figures 9 A–C.......... I. tenuicornis

– Antennomeres 5–10 not identical, 5–7 longer than 8–10, antennomeres 5–7 about 1.6 times longer than wide (Figure 4C), only female specimen known........................................ I. sahlbergi

4. Abdominal segments III–V dark brown to black; aedeagus as in Figures 8 A–C.......................................... I. sallaei

– Abdominal segments III–V dark orange to rufous or gradient between brown and orange; aedeagus not as above...................... 5

5. Abdominal segments III–VIII dark orange to rufous; antennae dark brown; aedeagus as in Figures 5 A–C........................... I. ashei

– Abdominal segments III–VIII with a colour gradient from dark brown to yellow, usually III–IV dark brown, V–VI rufous to orange, VII–VIII orange to yellow; antennae orange to yellow; aedeagus as in Figures 7 A–C......................................... I. hinojosai

Phylogenetic analysis

Branch and bound analysis in NONA produced a single most parsimonious tree ( Figure 12 ) with a length of 24 steps and CI51.0. Isanopus is robustly hypothesized to be monophyletic with 100% bootstrap values and Bremer support values of 5 (the highest allowed under the analysis settings). The monophyly of Isanopus is supported by 11 characters, eight of which are uniquely derived (3-0, 4-0, 5-0, 6-0, 11-0, 12-0, 13-0, 15-1).

Isanopus eptaskouros is the sister group to all remaining Isanopus species. The lineage consisted of the remaining species which is supported by 66% bootstrap and a Bremer support value of 1 and character states 7-1, 14-2, 16-1, 17-0 and 19-1, only of those (7-1, antennomere 11 subequal to 10). Isanopus sahlbergi and I. tenuicornis are the sister groups to a lineage consisting of I. ashei , I. hinojosai and I. sallaei . Despite the absence of any homoplasy on the tree, the characters used in the analysis do not provide enough phylogenetic resolution for I. sahlbergi and I. tenuicornis . The lineage of I. ashei , I. hinojosai and I. sallaei is supported by 96% bootstrap and a Bremer support value of 3. The character states supporting this lineage are 8-0, 9-1, 10-1 (type of punctuation on the posterior part of head, pronotum and scutellum respectively) and 16-2, the apical shape of the paramere. It is worth mentioning here that I. ashei , I. hinojosai and I. sallaei are distributed exclusively in Central America in contrast with the three other species of Isanopus that are distributed in South America. The sister group relationships of I. hinojosai and I. sallaei are supported by 61% bootstrap and s Bremer value of 1, as well as character state 18-1.

Figures

Figure 1. Habitus photographs of species of Isanopus. (A) I. tenuicornis. (B) I. sallaei.

Figures 2. Isanopus species, dorsum of head and pronotum. (A) I. ashei. (B) I. sahlbergi. (C) I. hinojosai. (D) I. eptaskouros.

Figure 5. Aedeagus of I. ashei. (A) Dorsal view. (B) Lateral view. (C) Detail of paramere, dorsal view.

Figure 6. Aedeagus of I. eptaskouros. (A) Dorsal view. (B) Lateral view. (C) Detail of paramere, ventral view.

Figure 7. Aedeagus of I. hinojosai. (A) Dorsal view. (B) Lateral view. (C) Detail of paramere, dorsal view.

Figure 8. Aedeagus of I. sallaei. (A) Dorsal view. (B) Lateral view. (C) Detail of paramere, dorsal view.

Figures 9. Aedeagus of I. tenuicornis. (A) Dorsal view. (B) Lateral view. (C) Detail of paramere, ventral view.

Figure 11. Distribution map of I. eptaskouros, I. sahlbergi and I. tenuicornis.

Figure 12. The single most parsimonious tree. Numbers above hatchmarks refer to characters, numbers below hatchmarks indicate state transformation, ACCTRAN optimization. Tree length524, consistency index51.0. Bootstrap values/Bremer support values are indicated below branches.