The Neotropical species of the genera Pseudespeson Lecoq , 1994 and Espeson SchaufuSS , 1882 ( Coleoptera : Staphylinidae : Osoriinae ) With 18 figures

A review of the Neotropical species of the genera Pseudespeson Lecoq, 1994 and Espeson Schaufuss, 1882 has been performed. Whereas no new species could be added to the genus Pseudespeson Lecoq, 1994, six new species were found in the genus Espeson Schaufuss, 1882. These are: E. adisi n. sp., E. dybasi n. sp., E. franiae n. sp., E. hermani n. sp., E. pecki n. sp., and E. simplex n. sp. One species, E. lenkoi Scheerpeltz, 1970, is synonymised with E. moratus Schaufuss, 1882. Thus, in total, 2 species of Pseudespeson Lecoq, 1994, and 13 species of Espeson Schaufuss, 1882 are actually known from Central and South America including the West Indies.


Introduction
The genus Pseudespeson was established by Lecoq (1994) on the basis of several species originally described in Espeson Schaufuss, 1882. Herman (2001 placed the two genera into the tribe Thoracophorinae, subtribe Glyptomina. However, according to Irmler (2010) a group of genera including Pseudespeson and Espeson attributed to the subtribes Glyptomina and Clavilispinina showed no close relation. Regarding the aedeagus, a close relation can be stated between Espeson and Pseudespeson. In particular, the paramera are unique in the subfamily and show no relation to any other genera in the subfamily Osoriinae. Therefore, a closer relation to the other genera of Clavilispina or Glyptomina cannot be stated. Due to the studies of Lecoq (1994) the species of the genus are distributed over the whole tropical regions from Central Africa to Indo-Malysia and Central and South America. According to Herman (2001) 18 species have been described world wide in the genus Espeson Schaufuss, 1882 and 12 species in the genus Pseudespeson Lecoq, 1994. In the Neotropics, Pseudespeson Lecoq, 1994 is represented by only two species. The genus is differentiated from the closely related genus Espeson by the following characters: front edge of mentum with comb, first abdominal segment anteriad not narrowed, 4 tarsomeres and 8 th antennomere smaller than 7 th and the following antennomeres. The two species are minute between 1.9 and 2.4 mm and colouration varies between light yellow to brown. The shape is very similar between the two genera Pseudespeson and Espeson with strongly emarginate sides of pronotum and elytra wider than pronotum. From South America 11 species have been described including 3 species from the Galapagos islands and only 3 species from Africa, 1 from the Philippines, 1 from the Seychelles islands, and 1 from New Guinea. If the 3 species from the Galapagos islands are excluded, on the Central and South American mainland, 8 species have been described which is by far much more than in the other continents. As 6 species are newly described here and 1 species is synonymised, a total of 13 species is actually known from the Central and South American mainland including the West Indies. Descriptions of all new species from the Central and South American mainland are provided here and in addition also that of already described species, because most of the old descriptions are insufficient.

Material and methods
The material studied in this investigation is presently deposited in the following public museums and private collections: The photographs were taken using a Makroskop M 420 (Wild, Herbrugg) in combination with a digital camera Leica EC3. A set of 10 to 15 photos were taken and combined using the program CombineZ5 (Hadley 2006). Length was measured in the middle of tagmata: head from clypeus to posterior edge, pronotum from anterior to posterior edge along midline, elytra from anterior edge at shoulders to posterior edge; width at the widest part of tagmata (head width includes eyes). In the measurement of total length, the abdominal intersegmental space is subtracted.

Diagnosis:
The species is larger than P. nitens and eyes are remarkably smaller. Eyes are only 0.25 times longer than temples, while they are tree times longer than temples in P. nitens. Additionally, punctation on pronotum and elytra is denser and coarser than in P. nitens.

Description:
Length: 2.4 mm. Colour: dark yellow, antennae and legs lighter yellow. Head: 0.30 mm wide, 0.48 mm long; eyes 0.25 times longer than temples; temples smoothly rounded; disc coarsely and densely punctate; distance between punctures 0.5 times as wide as diameter of punctures; on clypeus punctation slightly sparser; surface shiny, with weak longitudinally reticulate microsculpture.
Antennae with 2 nd and 3 rd antennomere equal in length; 4 th antennomere quadrate; the following ones wider than long and increasing in width; 8 th antennomere less wide than 7 th and 9 th antennomere and distinctly shorter.
Pronotum: 0.30 mm long, 0.48 mm wide; distinctly emarginate in front of posterior edge; only half as wide as at anterior edge; coarsely and densely punctate; still coarser and denser punctate than on head; distance between punctures on average 0.25 times as wide as diameter of punctures; surface shiny, with weak irregular microsculpture. Elytra: 0.50 mm long, 0.53 mm wide; with dense and deep punctation; distance between punctures similar as on pronotum; surface shiny, with weak irregular microsculpture; microsculpture slightly denser than on pronotum.
Abdomen with finer and sparser punctation than on elytra and microsculpture more distinct; thus, surface less shiny than elytra; laterally with long dark setae, tergite of last abdominal segment with distinct central tooth.

Diagnosis:
At present, only 2 species of the genus are known from the Neotropics. Therefore, the diagnosis given in P. crassulus informs about the differences between the two species.

Description:
Length: 2.0 mm. Colour: yellow, antennae and legs lighter yellow. Head: 0.25 mm wide, 0.35 mm long; eyes large, 3 times longer than temples; temples with distinct angles; punctation distinct, but sparse and moderately fine; distance between punctures on average wider than diameter of punctures; surface shiny with weak and sparse microsculpture. Antennae with 2 nd and 3 rd antennomere equal in length; 4 th to 6 th antennomeres not wider than preceding antennomeres; 4 th and 5 th antennomeres quadrate, 6 th one shorter, wider than long; antennomeres 7 to 11 distinctly wider than preceding antennomeres; 7 th antennomere quadrate, 8 th distinctly shorter and smaller; the penultimate antennomeres wider than long. Pronotum: 0.28 mm long, 0.38 mm wide; distinctly emarginate in front of posterior edge; 0.3 times as wide as at anterior angles; punctation slightly coarser and denser than on head, in particular on both sides of the midline; distance between punctures on average smaller than diameter of punctures; surface shiny and nearly polished; with weak irregular microsculpture. Elytra: 0.43 mm long, 0.45 mm wide; with similar punctation as on pronotum; surface polished.
Abdomen with finer and sparser punctation than on elytra and microsculpture more distinct than on fore body; scarcely shiny; laterally with long dark setae, tergite of last abdominal segment with distinct central tooth.

Diagnosis:
The species closely resembles E. titschacki in colour, shape of antennae, and shape of abdominal tergite VIII of male. In E. adisi the two pronotal impressions in the midline are absent, the apical part of the central lobe of the aedeagus is placed in a more or less rectangular angle to the basal part and the paramera are also angulated, whereas they are straight in E. titschacki. Posterior edge of abdominal tergite VIII of male is slightly obtuse in E. adisi, whereas it is of more semicircular shape in E. titschacki.

Description:
Length: 1.8 -1.9 mm. Colour: dark yellow, legs lighter yellow. Head: 0.23 mm long, 0.33 mm wide; eyes large and distinctly prominent; temples behind eyes narrowed to the neck without rectangular angle; setiferous punctation fine, but distinct; distance between punctures as wide as diameter of punctures; a midline without or with sparser punctures; setae pointing to the midline; surface with weak and sparse microsculpture, shiny, but not polished.
Antennae with 2 nd antennomere short and globular; 3 rd antennomere conical and slightly longer than 2 nd ; antennomeres 4 to 6 more or less quadrate; the following antennomeres wider than long and increasing in width except 8 th antennomere being smaller than 7 th and 9 th ; 10 th antennomere 1.5 times wider than long. Pronotum: 0.27 mm long, 0.33 mm wide; widest shortly behind anterior angle; slightly narrowed to posterior deep emargination; two long dark marginal setae and one dark seta at anterior edge; sides additionally with several dark shorter setae; setiferous punctation as on head; with irregular smooth midline; discal setae yellow pointing to midline; surface as on head with weak microsculpture and shiny, but not polished. Elytra: 0.35 mm long, 0.40 mm wide; widest in the posterior half; distinctly narrowed to shoulders; base distinctly deeper than disc; setiferous punctation and surface as on pronotum; sides with several long dark setae. Abdomen much finer and sparser punctate than elytra; surface less shiny; abdominal tergite VIII with few long dark setae in a more or less dense pubescence and obtuse posterior edge. Aedeagus with thick central part and nearly rectangular apical part; paramera also angulate, but with obtuse angle with basal and slender apical segment; apical transparent plate circular; diameter of transparent plate approximately half as wide as length of apical segment of paramera.

Etymology:
The species is named in honour of my passed friend Prof. Joachim Adis, who found this species in the Central Amazon near Manaus during his studies in the Várzea of the Amazon river.

Diagnosis:
The species resembles E. mexicanus and E. simplex in size and colour. It can be easily differentiated from these two species by the elongate antennae. Whereas in E. mexicanus and E. simplex antennae are only slightly longer than head and pronotum combined, antennae of E. dybasi are as long as head plus pronotum plus half of elytra. Moreover, the shape of the elytra also differs distinctly between E. dybasi and both E. mexicanus and E. simplex, respectively. Width of elytra of E. dybasi is more than 1.5 times as wide as pronotum, whereas it is only 1.3 times as wide in E. mexicanus and E. simplex. In all three species tergite VIII is slightly emarginate at posterior edge. In E. mexicanus the emargination is weak and smooth without distinct acute prominences at outer posterior angles. In E. dybasi a short stylus is placed at posterior angles, while an acute teeth is present in E. simplex.

Description:
Length: 2.3 mm. Colour: brown; elytra and antennae red; legs yellow. Head: 0.30 mm long, 0.40 mm wide; eyes distinctly prominent; temples half as long as eyes; smoothly rounded to neck; fore-head distinctly narrowed to acute front edge of clypeus; densely and deeply punctate; distance between setiferous punctures on average less than 1/2 of diameter of punctures; vertex with impunctate midline; without microsculpture; surface shiny.
Antennae longer than head and pronotum combined; 2 nd antennomere short; 3 rd conical antennomere longer than 2 nd ; 3 rd to 7 th antennomeres longer than wide; 8 th antennomere slightly narrower and shorter than preceding and following antennomeres. Pronotum: 0.38 mm long, 0.38 mm wide; smoothly rounded in anterior half; distinctly emarginate in posterior half; lateral margin not visible in dorsal aspect; setiferous punctures dense and coarse; with narrow impunctate midline; on average distance between punctures half as wide as diameter of punctures; with small, but deep circular impression in central position of posterior half. Elytra: 0.55 mm long, 0.60 mm wide; sides smoothly rounded; widest in posterior third; setiferous punctation distinctly sparser and weaker than on pronotum; distance between punctures at least as wide as diameter of punctures, but on average distinctly wider.
Abdomen with abdominal tergite III densely and deeply punctate; distance between punctures 1/2 as wide as diameter of punctures; density of punctation decreasing from tergite III to tergite VII; distance between punctures on tergite VII 2 to 3 times as wide as diameter of punctures; abdominal tergite VIII widely emarginate and with acute angles; on top of each acute angle a short stylus; at base of tergite VIII two setiferous pores within irregular dark spots.
Aedeagus with more or less straight central lobe; paramera straight and with small irregular plate at apex.

Etymology:
The specific name refers to the name of its first collector Dr. H. S. Dybas. Antennae longer than head and pronotum combined; 2 nd and 3 rd antennomere equal in length; following 4 antennomeres at least scarcely longer than wide and slightly increasing in width; penultimate antennomeres quadrate. Pronotum: 0.30 mm long, 0.33 mm wide; distinctly emarginate in front of posterior edge; 0.3 times smaller than at anterior angles; in the front half of a longitudinal impression in the midline; in the posterior half a circular impression; deeply and densely punctate; distance between punctures on average as wide as diameter of punctures; surface shiny, nearly polished, without microsculpture. Elytra: 0.40 mm long, 0.40 mm wide; with similar deep, but sparser punctation as on pronotum; distance between punctures is on average slightly wider than diameter of punctures; surface shiny, with weak irregular microsculpture.

Espeson euplectoides
Abdomen densely and deeply punctate; punctation similar as on elytra; without microsculpture; surface shiny; laterad with long dark setae, abdominal tergite VIII of male slightly narrowed distad and smoothly emarginate at posterior edge; with few longer and darker setae among short sparse pubescence.
Aedeagus slender with smoothly curved apical part; paramera slightly longer than central lobe and with short transparent plate.

Description:
Length: 2.7 mm. Colour: brown, elytra lighter reddish, legs dark yellow. Head: 0.30 mm long, 0.43 mm wide; more or less globular in shape; widest at eyes and with rounded temples; fore-head triangular; setiferous punctation deep and dense; on average distance between punctures less than half as wide as diameter of punctures; with moderately wide impunctate midline; surface without microsculpture and polished. Antennae slightly longer than head and pronotum combined; 2 nd antennomere globular, half as long as conical 3 rd antennomere; 4 th to 6 th antennomere more or less quadrate; following antennomeres slightly wider than long and slightly increasing in width with exception of 8 th antennomere; 8 th antennomere slightly smaller than 7 th and 9 th antennomeres. Pronotum: 0.37 mm long, 0.45 mm wide; widest in anterior half; sides of anterior half rounded; in posterior half deeply emarginate; lateral margin in anterior half present, but not visible in dorsal aspect; setiferous punctation coarse and dense; punctures distinctly deeper and larger than head; distance between punctures less than half as wide as diameter of punctures; surface without microsculpture and polished. Elytra: 0.63 mm long, 0.65 mm wide; sides smoothly rounded from shoulders to posterior angles; anterior edge distinctly emarginate; posterior edge slightly emarginate; setiferous punctation irregular; size of punctures variable; fine micro-punctures between punctures of normal size and few larger and deeper punctures; on average distance between punctures as wide as diameter of punctures; surface without microsculpture and polished.
Abdomen on anterior segments III to V coriaceously punctate; density of punctation decreasing to posterior segments; segment VIII twice as long as preceding segments; posterior edge of tergite VIII deeply emarginate; at outer posterior angles with short stylus; with few long and black setae and more dense fine setation; at posterior emargination with transverse lighter band with longitudinal striae; at base of tergite VIII two lighter spots surrounded by darker circle.
Aedeagus with apical part of central lobe as long as basal part; apical part smoothly rounded; paramera with small transparent plate at apex; diameter of transparent plate not wider than apical short stylus; paramera with triangular prominence at middle.

Etymology:
The specific name refers to its collector H. Frania.

Diagnosis:
E. hermani is one of the darker reddish Neotropical Espeson species. Among these species, it is conspicuous by the slightly lighter red elytra and the longitudinal impression in the anterior half of the pronotum. In the male, the species can be easily identified by the central spine at abdominal tergite VIII, the large triangular shape of the transparent lobe of the paramera, and the short apical part of the central lobe of the aedeagus.

Description:
Length: 2.0 mm. Colour: reddish; pronotum and elytra lighter red than head and abdomen; legs yellow. Head: 0.25 mm long, 0.35 mm wide; eyes large and prominent; nearly four times longer than short temples; labrum more or less triangular with short acute apex; setiferous punctation dense and deep; distance between punctures less than half as wide as diameter of punctures; a wide midline impunctate; surface with extremely weak remains of microsculpture between punctures; midline without microsculpture and more or less polished. Antennae distinctly longer than head and pronotum combined; 2 nd antennomere more or less globular; conical 3 rd antennomere slightly longer than 2 nd ; 4 th to 5 th antennomeres more or less quadrate; 6 th slightly wider than long; following antennomeres slightly increasing in width and wider than long except smaller 8 th antennomere. Pronotum: 0.30 mm long, 0.35 mm wide; with sides rounded in anterior 2/3 rd and emargination in posterior 1/3 rd ; fine lateral margin visible in anterior half in dorsal aspect; setiferous punctation similar as on head; distance between punctures irregular; laterad on average half as wide as diameter of punctures; impunctate midline in anterior half and there with longitudinal impression; surface with weak remains of microsculpture; midline without microsculpture; shiny; at posterior edge a transverse band with coriaceous ground-sculpture. Elytra: 0.45 mm long, 0.50 mm wide; with sides smoothly rounded and with emargination at both anterior and posterior edge; setiferous punctation distinctly wider than on pronotum; distance between punctures on average as wide as diameter of punctures; a sparse micro-punctation between normal punctures. Abdomen finely and sparsely punctate; density of setiferous punctation decreasing posteriad; on tergites II to V transverse impressions with coriaceous ground sculpture; tergite VIII of male deeply emarginate at posterior edge; emargination divided by acute spine; a stripe of fine longitudinal striae at posterior emargination. Aedeagus with short straight apical part and two times longer basal part; paramera slightly longer than central lobe and with large more or less triangular transparent plate; diameter of transparent plate more than half as long as length of paramera.

Etymology:
The specific name refers to its collector Lee Herman.

Diagnosis:
The species resembles E. simplex, E. franiae, E. dybasi, and E. hermani in the darker reddish colouration and it size of at least 2.0 mm. It can be differentiated from the similarly large E. hermani by the position of the pronotal impression. In E. mexicanus the longitudinal impression is placed in the posterior half and drop-shaped, whereas in E. hermani the longitudinal impression is placed in the anterior half. Moreover, the elytra in E. hermani are lighter red than head and pronotum, whereas no different colouration between head, pronotum, and elytra is found in E. mexicanus. In males, tergite VIII and aedeagus distinctly differ between the two species. E. simplex, E. dybasi, and, in particular, E. franiae are larger with at least 2.3 mm length. In E. simplex a pronotal impression is absent, in E. dybasi and E. franiae the pronotal impression is placed also in the posterior half, but with a circular shape.

Description:
Length: 2.0 mm. Colour: dark reddish, elytra dark yellow, antennae and legs yellow. Head: 0.28 mm long, 0.36 mm wide; eyes 0.3 times longer than temples; temples smoothly rounded; punctation dense and deep; distance between punctures half as wide as diameter of punctures; a space in the middle of disc without punctures; without microsculpture; surface polished. Antennae as long as head and pronotum combined; 2 nd and 3 rd antennomeres equal in length; following antennomeres quadrate and slightly increasing in width; 8 th antennomere slightly smaller than preceding and following antennomeres. Pronotum: 0.30 mm long, 0.38 mm wide; distinctly emarginate in front of posterior edge; sides in front of emargination smoothly rounded; widest in anterior third; 0.3 times wider than at posterior angles; punctation deep and dense; on average distance between punctures half as wide as diameter of punctures; at posterior edge with coriaceous punctation; a longitudinal impression in the anterior half; with sparse and weak microsculpture; surface shiny. Elytra: 0.48 mm long, 0.53 mm wide; punctation similar as on pronotum; without microsculpture; surface polished. Abdomen with sparser and finer punctation as on elytra, but microsculpture more distinct; surface less shiny than on elytra; abdominal tergite VIII slightly narrowed posteriad and with undulate straight edge; with few longer setae among sparse pubescence.
Aedeagus with slender, more or less straight apical part placed in obtuse angle to basal part of central lobe; paramera thick and long with large apical transparent plate; diameter of apical plate nearly as long as length of apical segment of paramera.

Diagnosis:
Compared to the other yellow species, E. microphthalmus can be differentiated by the overall parallel shape of the body that resembles a species of the genus Pseudespeson; but abdominal segment III is slightly narrowed and tergite VIII is without central spine. The pronotal emargination is deep and its sides are nearly parallel with a distinct lateral margin, whereas they are concave in the other yellow Espeson species and lateral margins are absent or extremely narrow. A dorsal impression is absent as in E. adisi, but in E. adisi the shape of the pronotal emargination is concave and abdominal segment III and IV are narrowed at base. Unfortunately, only the type female is known.

Description:
Length: 1.9 mm. Colour: yellow, antennae and legs lighter yellow. Head: 0.25 mm long, 0.30 mm wide; eyes as large as temples; temples smoothly rounded; punctation dense and deep; distance between punctures half as wide as diameter of punctures; without microsculpture; surface polished. Antennae shorter than head and pronotum combined; 2 nd globular, 3 rd conical, both antennomeres equal in length; following 3 antennomeres at least slightly wider than long and not wider than preceding antennomeres; antennomeres 7 to 11 distinctly wider than preceding ones and distinctly wider than long; 8 th antennomere slightly smaller than preceding and following antennomere and three times wider than long; penultimate antennomeres twice as wide as long.
Pronotum: 0.28 mm long, 0.38 mm wide; distinctly emarginate in front of posterior edge; with deep impression in the emargination; widest in the middle and slightly narrowed to the anterior angles; deeply and densely punctate on the disc, punctation partly coriaceous; without microsculpture; surface polished. Elytra: 0.45 mm long, 0.43 mm wide; punctation irregularly dense; distance between punctures as wide as or smaller than diameter of punctures; without microsculpture; surface polished.
Abdomen with similar punctation as on elytra and weak microsculpture; surface shiny, but less shiny than elytra; tergite of last abdominal segment rounded.

Diagnosis:
The species is certainly closely related to E. titschacki and E. adisi concerning the yellow colour, shape of elytra, and structure of aedeagus. The species can be easily distinguished from the two species by the pair of weak pronotal impressions on both sides of the midline in front of posterior edge. Furthermore, it is differing from E. adisi by the slightly smaller size and shorter paramera. The shape of abdominal tergite VIII in males is very similar in both species, but posterior edge in E. moratus is slightly emarginate, whereas it is more obtuse in E. adisi and semicircular in E. titschacki.
Head: 0.20 mm long, 0.27 mm wide; eyes not prominent, but large, as long as temples; temples smoothly rounded behind eyes to distinctly separated neck; setiferous punctation distinct, moderately fine; distance between punctures on average as wide as diameter of punctures; on disc sparser than laterally; a wide midline without punctures; surface without microsculpture and polished. Antennae as long as head and pronotum combined; 2 nd antennomere globular, 3 rd conical, but not longer than 2 nd ; 4 th antennomere wider than long, but not wider than 3 rd ; the following antennomeres increasing in width; the penultimate antennomere 2 times wider than long. Pronotum: 0.20 mm long, 0.23 mm wide; widest in the anterior half; smoothly rounded to the front edge, anterior angles scarcely present; distad with deep emargination; setiferous punctation similar as on head, but slightly coarser; distance between punctures half as wide as diameter of punctures; with pair of weak longitudinal impressions on each side of the midline in the posterior half; surface without microsculpture and polished. Elytra: 0.30 mm long, 0.33 mm wide; widest in the middle; slightly narrowed to the shoulders and the posterior edge; setiferous punctation distinctly sparser and finer than on pronotum; distance between punctures on average two times wider than diameter of punctures; surface without microsculpture, polished.
Abdomen with setiferous punctation still finer and sparser than on elytra; setae pointing posteriad; surface with weak microsculpture, less shiny than elytra; abdominal tergite VIII of male differing from female tergite; posterior edge of male tergite widely emarginate and with indistinct lateral prominence that is expressed by two thicker setae; small midline without setae. Aedeagus with thick and large basal part in central lobe and sharply angulate short apical part; paramera also short, but slightly longer than central lobe; apical transparent plate circular.

Remarks:
Unfortunately the Brazilian specimens described as E. lenkoi by Scheerpeltz (1970) are all females. A significant difference between the West Indian E. moratus specimens could not be found. Scheerpeltz (1970) also described the high similarity of the two species. He focused on the wide antennomeres of E. lenkoi compared to E. moratus. However, also E. moratus is characterised by extremely wide antennomeres. Therefore, although hesitating, I synonymise the two species. Head: 0.20 mm long, 0.33 mm wide; with eyes not prominent and temples nearly as long as eyes; fore-head nearly parallel in front of eyes; clypeus triangular; labrum with short spine in middle; punctation dense and deep; distance between punctures irregular; on average slightly smaller than diameter of punctures; neck with dense coriaceous punctation; with small impunctate midline; surface without microsculpture and shiny. Antennae nearly as long as head and pronotum combined; 2 nd antennomere globular and nearly as long as conical 3 rd antennomere; 4 th to 6 th antennomeres more or less quadrate; 7 th to 10 th antennomeres increasing in width and wider than long; except smaller 8 th antennomere. Pronotum: 0.25 mm long, 0.34 mm wide; rounded in anterior two third; in posterior third emarginate; with small margin in posterior half in front of emargination; anterior half not margined; setiferous punctation more regular; as deep as on head, but less dense; on average distance between punctures as wide as diameter of punctures; without impression on disc; surface without microsculpture and shiny. Elytra: 0.31 mm long, 0.38 mm wide; with smoothly rounded sides, but not distinctly wider than pronotum; punctation less dense and deep than on pronotum and surface still more shiny.

Espeson nevermanni
Abdomen only with segment III with deep transverse impression at base; following segments without transverse impression; setiferous punctures distinctly finer than on fore-body.

Diagnosis:
Compared with the small yellow species, E. titschacki, and E. adisi, E. pecki is easily to identify by the extremely small eyes. The species is as small as E. titschacki and both species are slightly smaller than E. adisi. Antennae are slightly shorter than in E. titschacki. In E. titschacki antennae are as long as head and pronotum combined, whereas they are slightly shorter than pronotum in E. pecki. Both species, E. pecki and E. titschacki, can be distinguished from E. adisi by the presence of two deep impressions on the pronotum, whereas E. adisi has no impression on pronotum. E. venezuelanus that is also similar to these three species is slightly darker. In males, the deep emargination of abdominal tergite VIII resembles that in E. simplex, but E. simplex is much larger, and punctation of tergite VIII is denser. Furthermore, the semicircular large apical plates of paramera are unique in the Neotropical Espeson species.
Head: 0.20 mm long, 0.25 mm wide; eyes extremely small; only four or five ocellae; nearly invisible in dorsal aspect; temples twice as long as eyes and convexly prominent; fore-head straightly narrowed to more or less acute front edge of clypeus; setiferous punctation moderately dense and fine; on clypeus finer and denser than on lateral part of vertex; disc with impunctate midline; surface shiny; laterad with remains of weak microsculpture; disc polished. Antennae nearly as long as head and pronotum combined; 1 st and 2 nd antennomere oblong, 3 rd conical; antennomeres 1 to 3 nearly equal in length; antennomere 4 and 5 more or less quadrate; following antennomeres wider than long; 8 th antennomere narrower and smaller than antennomeres 7 and 9; 10 th antennomere nearly twice as wide as long. Pronotum: 0.23 mm long, 0.27 mm wide; with weak lateral margin; only visible in posterior half in dorsal aspect; deeply emarginate in posterior half; posterior edge only half as wide as width in anterior half; setiferous punctation deeper and coarser than on head; distance between punctures on average only half as wide as diameter of punctures; in anterior and posterior half each a small, but deep impression; surface shiny; laterad with remains of microsculpture, but surface mostly polished. Elytra: 0.26 mm long, 0.33 mm wide; with setiferous punctation slightly weaker and sparser than on pronotum; with remains of microsculpture, but surface mostly polished and shiny.
Abdomen with coarser punctation on anterior segments than on distal segments; microsculpture slightly more distinct than on elytra and, thus, surface less shiny; tergite VIII of male deeply emarginate in middle and with long acute teeth at outer angles; sparsely punctate also at lateral margin.
Aedeagus with long and thick basal part; apical part more or less straight and only half as long as basal part; paramera with large apical plate of semicircular shape.

Etymology:
The specific name refers to its collector James Peck.  27.12.1965-7.1.1966.

Diagnosis:
The impressions on the pronotum are absent in this species and in this respect it resembles E. adisi and E. microphthalmus. But in size and colour it is more similar to E. mexicanus. Compared to E. microphthalmus, elytra of E. simplex are wider and sides are curved, whereas sides are more or less parallel in E. microphthalmus. The species is unique by the shape of the abdominal tergite VIII of male that laterally carries a distinct tooth. The two specimens without date were already labelled as holotype and paratype by Wendeler, but never described.

Description:
Length: 2.3 mm. Colour: dark red, head brown, leg and antennae lighter red. Head: 0.25 mm long, 0.33 mm wide; eyes not prominent and small; temples well developed, at least 0.3 times longer than eyes; temples behind eyes shortly parallel, then rounded in a smooth curve; neck distinctly separated from the head; setiferous punctation coarse and dense; distance between punctures less than half as wide as diameter of punctures; on the disc with distinct impunctate midline widened to the front; clypeus sparsely punctate; surface without microsculpture and polished.
Antennae as long as head and pronotum combined; 2 nd antennomere globular, 3 rd conical, but not longer than 2 nd , antennomeres 4 and 5 quadrate, the following antennomeres slightly wider than long; 8 th antennomere slightly smaller than preceding and following antennomeres. Pronotum: 0.30 mm long, 0.37 mm wide; widest in the anterior third, rounded in a smooth curve to the front edge; without distinct front angles; posteriad with emargination, forming a nearly rectangular angle; setiferous punctation coarse and dense, puncture still deeper and larger than on head; distance between punctures less than 1/4 as wide as diameter of punctures; surface without microsculpture and polished. Elytra: 0.43 mm long, 0.50 mm wide; widest in the posterior half; posterior angles rounded in a smooth curve; shoulders indistinct, too; setiferous punctation as large as on pronotum, but slightly sparser; between setiferous coarse punctation a finer and sparser micro-punctation; distance between coarser punctures irregular, on average half as wide as diameter of punctures. Abdomen with anterior tergites as coarsely and densely punctate as on head, posterior tergite sparser and finer punctate; abdominal tergite VIII in male emarginate at posterior edge and with lateral tooth; two long setae inserted anteriad and with relatively long and dense pubescence, but with a wide midline without setae. Aedeagus slender with slightly angulate apical part; basal segment of paramera thick, apical segment slender; apical transparent plate circular; placed on a short stylus.

Etymology:
The specific name was adopted from the preliminary name given by Wendeler. The name derived from the same Latin word simplex meaning simply and presumably refers to the simple surface of the pronotum without impressions.

Diagnosis:
The species resembles E. mexicanus in punctation of the fore-body and the impressions of the pronotum. But E. mexicanus is larger than E. subtilis and the impression in the anterior half of the pronotum is longitudinal, whereas it is circular in E. subtilis.

Description:
Length: 1.8 mm. Colour: red, head darker red, legs and antennae dark yellow. Head: 0.20 mm long, 0.30 mm wide; eyes scarcely prominent; temples continuously narrowed to the neck; only half as long as eyes; setiferous punctation coarse and deep; distance between punctures only half as wide as diameter of punctures; a wide smooth midline impunctate; surface without microsculpture and polished. Antennae as long as head and pronotum combined; with 2 nd antennomere quadrate, 3 rd conical and not longer than 2 nd , the following antennomeres more or less quadrate and increasing in width; penultimate antennomeres only slightly wider than long. Pronotum: 0.27 mm long, 0.30 mm wide; widest in the middle, narrowed in a smooth curve to front angle, emargination in front of the posterior angle forming an obtuse angle; setiferous punctation still deeper and larger than on head; distance between punctures half as wide as diameter of punctures; a wide midline without punctures; within midline a short longitudinal impression in anterior half and a circular impression in posterior half; surface without microsculpture and polished. Elytra: 0.37 mm long, 0.40 mm wide; widest in the posterior half, with setiferous punctation differing in size; coarser punctation sparser than on pronotum, distance between punctures on average as wide as or wider than diameter of punctures, between coarser punctation a sparse finer punctation; surface without microsculpture and polished. Abdomen with punctation as coarse and dense as on pronotum, on each abdominal tergite a wide impunctate midline; posterior edge of tergite VIII in male smoothly rounded; without emargination.
Aedaegus with thick basal part of central lobe and apical part placed in rectangular angle to basal part. The paramera not found in the single male specimen.

Remarks:
No differences could be found between the Mexican specimens and the South American specimens, which let suppose that the species might also occur in other Central American countries.

Discussion
The remarkable structure of the aedeagus, in particular, the structure of the paramera with the suction-cup-like apical appendix, at least in the genus Espeson, is unique in the family Staphylinidae. Moreover, it seems that the paramera are divided into two parts, similar to the subfamily Aleocharinae. Although the overall habit of the fore-body resembles that in the genus Glyptoma Erichson, 1839, the structure of the aedeagus suggests that both genera are not closely related to Glyptoma as already emphasised by Irmler (2010). Lecoq (1994) mentioned the smaller 8 th antennomere as characteristic to differentiate Pseudespeson from Espeson, but as the comparison of all Espeson species showed the size of the 8 th antennomere varies in this genus. In several species, e.g. E. moratus, the 8 th antennomere equals 7 th and 9 th antennomere in size, but in other species, e.g. E. microphthalmus and E. nevermanni, it is distinctly smaller. In some species, e.g. E. simplex and E. pecki, 8 th antennomere is only slightly smaller than 7 th or 9 th antennomeres. Thus, this character is not appropriate to differentiate the two genera. Furthermore, Lecoq (1994) also noted the shape of the last abdominal tergite as differentiating character between the two genera. Indeed, in the two Neotropical Pseudespeson species the last abdominal tergite is of triangular shape with short apical spine. In Espeson, a triangular shape of the last tergite without spine is found in E. titschacki, a central spine at an emarginate posterior edge is found in E. hermani. The distinct sexual dimorphism in Espeson with simple triangular shape of last abdominal tergites, i.e. E. titschacki, and various shapes in males indicates that the variance in the shape of the last abdominal tergite might be high and provide no valuable differentiating character, too. The geographic distributions of the species are still vague due to the rare records of the species. The genus Pseudespeson was recorded from extreme distant locations, i.e. Guadeloupe and southern Brazil, which indicates that species might occur also in other Neotropical countries. In particular, P. nitens that was recorded from The Caribbean, Brazil and Peru shows a wide distribution, but seem to be rare. In contrast, the species of the genus Espeson are widely distributed from Mexico to Argentina. Some, e.g. E. moratus and E. titschacki, seem to be distributed over the whole Neotropical region or at least in a wide area of South America and the Caribbean. Others, i.e. E. dybasi, were found from several localities of southern Central America and the northern Andean region of South America. Thus, similar geographical distributions can be assumed as in other osorine genera (Irmler 2007(Irmler , 2010.
Concerning the ecology of the species, our knowledge is similarly poor as for the geographical distribution. Referring to the information given on the labels by the collectors, many specimens were found in litter of rain forests. Nevertheless, also other habitats are recorded, e.g. E. adisi was also found by tree eclectors, E. nevermanni was found under bark, and E. moratus even in nests of ants. These records indicate that a variety of habitats may be inhabited by the species.