Microraphes Franz

Jałoszyński, Paweł, 2013, Revision of Neotropical genera Microraphes Franz, Heteroscydmus Franz and Mimoscydmus Franz (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 3722 (2), pp. 245-266 : 246-252

Microraphes Franz

Microraphes Franz, 1980: 222 . Type species: Microraphes pygmaeus Franz, 1980 (monotypy).

Revised diagnosis. Male: head short, with vertex not expanded dorso-caudad; occipital constriction only slightly narrower than vertex; thick and long bristles absent on head but present on sides of prothorax; frontoclypeal groove absent; submentum not demarcated laterally from hypostomae by sutures; maxillary palpomere III stout; antennae with indistinctly delimited club composed of antennomeres IX–XI; pronotum with fine lateral edges visible in posterior third; base of pronotum with long transverse groove, with short sub-lateral carinae and without pits; basisternal part of prosternum about as long as procoxal cavities; prosternum with rudimentary intercoxal process developed as a low (i.e., only slightly expanding ventrally) and short protuberance in anterior part of area between procoxal cavities; prothoracic hypomeral ridges complete; pronotosternal sutures visible only along sides of basisternal part of prosternum; mesoventral intercoxal process long, narrow and moderately strongly expanding ventrally (but not keel-shaped); mesoventrite with asetose lateral impressions behind anterior ridge, without setose impressions; mesothorax without lateral foveae; mesocoxal projection with short and barely discernible posterior lobe; metacoxae narrowly separated by subtrapezoidal metaventral intercoxal process without median notch; each elytron with single rudimentary and asetose basal fovea with two subcuticular sockets (visible only in transparent mounts); aedeagus symmetrical. Female diagnostic characters unknown.

Redescription. Body of male ( Fig. 1 ) moderately convex, elongate and slender, with moderately long appendages, BL slightly exceeding 0.5 mm; cuticle glossy, yellowish-brown with darkened head, with strongly and strikingly setose sides of pronotum and finely setose remaining body parts.

Head ( Figs. 1 , 5–6 ) with anterior part (in front of occipital constriction) transverse, with large eyes; occipital constriction ( Figs. 5–6 ; occ) only slightly narrower than vertex; tempora ( Fig. 5 ; tm) moderately long and strongly convergent caudad, without bristles; vertex ( Fig. 5 ; vt) broader than long, convex, not projecting dorso-caudad; frons ( Fig. 5 ; fr) transverse and subrectangular with arcuate anterior margin slightly expanding anterad in middle, posteriorly confluent with vertex; fronto-clypeal groove absent; antennal insertions broadly separated.

Labrum transverse with rounded anterior margin. Mandibles ( Fig. 6 ; md) barely visible in the only available specimen, symmetrical, with slender and curved distal part, mesal tooth and prostheca not visible. Each maxilla ( Fig. 6 ) with subtriangular basistipes ( Fig. 6 ; bst), elongate galea ( Fig. 6 ; gal) and lacinia ( Fig. 6 ; lac) and moderately long maxillary palp ( Fig. 6 ; mxp) composed of elongate palpomere I, strongly elongate, pedunculate palpomere II, broad and stout palpomere III broadest in distal third, and small, elongate, subconical and pointed palpomere IV with distinctly delimited apical part.

Labium ( Fig. 6 ) with transverse submentum ( Fig. 6 ; smn) not demarcated posteriorly and fused laterally with postcardinal parts of hypostomae, subtrapezoidal mentum ( Fig. 6 ; mn); and short prementum bearing narrowly separated at bases small 3-segmented labial palps ( Fig. 6 ; lp). Hypostomal ridges ( Fig. 6 ; hr) short, rapidly bent mesad behind cardines.

Gular plate ( Fig. 6 ; gp) large and distinctly narrowing anterad; gular sutures ( Fig. 6 ; gs) superficial; posterior tentorial pits ( Fig. 6 ; ptp) small but distinct, located at base of submentum, anterior to transverse arcuate impression delimiting ventrally 'neck region' from anterior part of head.

Antennae ( Fig. 1 ) with indistinctly delimited club composed of antennomeres IX–XI.

Pronotum ( Fig. 1 ) in dorsal view subrectangular with weakly arcuate anterior and posterior margins, sides rounded in anterior half and slightly concave in posterior third, anterior and posterior corners distinct; marginal carinae developed as fine edges visible in posterior third of pronotum; base of pronotum with distinct and long transverse groove and short sub-lateral carinae, without pits; sides of pronotum with dense, thick and long bristles ( Fig. 7 ).

Prosternum ( Fig. 7 ) with long basisternal part ( Fig. 7 ; bst) distinctly demarcated from procoxal cavities ( Fig. 7 ; pcc) by arcuate carina; median part of sternum with rudimentary prosternal intercoxal process developed as a small protuberance not connected to posterior margin of prosternum; procoxal sockets ( Fig. 7 ; pcs) closed by broad postero-lateral lobes of prosternum; hypomera ( Fig. 7 ; hy) elongate, each divided into broad lateral part and narrow internal (adcoxal) part, adcoxal parts of hypomera anteriorly fused with prosternum, so that pronotosternal sutures ( Fig. 7 ; nss) visible only along sides of basisternal parts of prosternum; hypomeral ridges ( Fig. 7 ; hyr) complete, anteriorly connected to pronotosternal sutures.

Mesonotum very small, approximately heart-shaped, with concave lateral margins of subtrapezoidal mesocutellum barely visible between bases of elytra; mesoscutoscutellar suture present.

Mesoventrite ( Fig. 8 ) with narrow anterior ridge ( Fig. 8 ; ar); mesoventral intercoxal process ( Fig. 8 ; msvp) narrow and moderately expanded ventrally, anteriorly connected with anterior ridge, with lateral pits or impressions on mesal margins of asetose lateral impressions ( Fig. 8 ; ai) and slightly behind them, posterior part of mesoventral intercoxal process with short posterior arms ( Fig. 8 ; pa); mesanepisternum with moderately long prepectus ( Fig. 8 ; pre) and posterior part largely hidden in ventral view; mesepimeron not visible in ventral view; sides of mesothorax without foveae; mesocoxal projections ( Fig. 8 ; mcp) with mesocoxal sockets ( Fig. 8 ; mscs) located on their mesoventral surface and with small, barely discernible and asetose posterior lobes ( Fig. 8 ; pl).

Metaventrite ( Fig. 8 ; vIII) slightly transverse, anteriorly fused with mesoventrite, posteriorly moderately deeply bisinuate and with narrow median subtrapezoidal metaventral intercoxal process ( Fig. 8 ; mtvp) devoid of median notch. Metanepisterna and metepimera narrow.

Metafurca ( Fig. 8 ) with very short and broad stalk and divergent lateral furcal arms ( Fig. 8 ; mtfa).

Elytra ( Fig. 1 ) oval, each with single rudimentary and asetose basal fovea located in shallow basal impression, in transparent mount two rudimentary subcuticular sockets are visible beneath opening of fovea; humeral calli well-marked and developed as longitudinal protuberances; elytral apices unmodified, separately rounded.

Hind wings well-developed, about twice as long as elytra.

Legs ( Figs. 1 , 8 ) moderately long and slender; procoxae subglobose, mesocoxae elongate, metacoxae transverse; all trochanters short; all femora weakly clavate; tibiae short and slightly thickening distally; tarsi short and stout.

Abdominal sternites unmodified, suture between VII and VIII barely marked.

Aedeagus ( Figs. 22–23 ) symmetrical, lightly sclerotized and thin-walled, parameres absent (but see Remarks).

Distribution and composition. Microraphes is represented by a single species known from the northern part of Brazil ( Fig. 35 ).

Remarks. Microraphes was originally defined by Franz (1980) as a genus most similar to Neuraphes , but clearly differing in a sharply demarcated antennal club composed of three antennomeres; the pronotum with a long and thick vestiture on the sides; fine lateral edges of the pronotum visible only in its posterior fourth; but with the aedeagus similar to that of Neuraphes , without parameres. I fail to find any similarity between Microraphes and Neuraphes in important structures. These genera differ in a number of characters, and even the differences and similarities listed by Franz seem incorrectly interpreted. The antennal club of Microraphes pygmaeus ( Fig. 1 ) is not in fact so sharply delimited as stated by Franz, and the aedeagus of Neuraphes always has parameres (e.g., Jałoszyński 2008, 2010). It is uncertain whether the aedeagus of Microraphes has the parameres or not, the absence of these structures in the only known specimen may be a result of a previous unskillful preparation, as discovered in some other specimens from the Franz Coll. (Jałoszyński, unpublished obs.). Microraphes differs from Neuraphes in a short head (elongate in Neuraphes ); the frontoclypeal groove absent (incomplete but present in Neuraphes ); the very short and sub-vertical frontoclypeal region in front of antennal insertions (long and subhorizontal clypeus in Neuraphes ); the submentum not demarcated from hypostomae by lateral sutures (lateral sutures present in Neuraphes ); the posterior tentorial pits located anterior to the arcuate transverse constriction separating ventrally the 'neck region' of the head (posterior tentorial pits in Neuraphes located in the groove separating ventrally the 'neck region', between the anterior margin of the gular plate and the posterior margin of elongate subtrapezoidal submentum); the complete transverse ante-basal groove on pronotum (groove interrupted in middle and often accompanied by a short median longitudinal carina or wrinkle in Neuraphes ); the prothoracic hypomera with hypomeral ridges (ridges absent in Neuraphes ); the basisternal part of prosternum about as long as procoxal cavities (much shorter in Neuraphes ); the prosternal intercoxal process developed only in the anterior part of the area between procoxal cavities (a fine but complete prosternal intercoxal carina in Neuraphes ); the bristles on sides of pronotum (only thin setae in Neuraphes ); the absence of setose lateral impressions of the mesoventrite (present in Neuraphes ); rudimentary and asetose basal elytral foveae (a single large and setose fovea on each elytron in Neuraphes ); and the aedeagus, which does not have any of the distal sclerotized plates characteristic of Neuraphes .

The head of Microraphes pygmaeus resembles that of Microscydmus nanus in its general shape and the short, broad submentum not separated laterally by sutures. Also ventral prothoracic structures are similar in Microscydmus and Microraphes , with the pronotosternal sutures visible only along lateral margins of the basisternal part of sternum and posteriorly connected to the hypomeral ridge, while the anterior part of prosternum (i.e., anterior to procoxal cavities but behind the basisternal region) is largely fused with the internal part of the prothoracic hypomeron ( Fig. 7 ). Both genera have also the thick and straight bristles on the sides of the pronotum ( Fig. 7 ). Moreover, the mesoventrite in Microscydmus and Microraphes ( Fig. 8 ) is also highly similar, except a densely setose transverse area behind asetose impressions in Microscydmus , absent in Microraphes . Microraphes differs clearly from Microscydmus in the sculpture of the pronotal base (a deep transverse groove in Microraphes vs. two pairs of pits in Microscydmus , of which the internal pair is large and approximate or adjacent in middle); the basal elytral foveae (one rudimentary and asetose fovea with two subcuticular sockets in Microraphes vs. one large and setose fovea in Microscydmus ); the setose impression of mesoventrite (absent in Microraphes vs. present in Microscydmus ); and the mesoventral intercoxal process (long, anteriorly connected to the anterior ridge of the mesoventrite in Microraphes vs. short, not connected to the anterior ridge in Microscydmus ). Major differences between Microscydmus and all genera treated in the present paper are compiled in Table 1.

Microraphes pygmaeus Franz ( Figs. 1 , 5–8 , 22–23 , 31 , 35 )

Microraphes pygmaeus Franz, 1980: 222 , Fig. 209.

Material studied. Holotype: ♂: three labels ( Fig. 31 ): "Umg. Manaus / Amazonasgebiet / Brasil, lg. L. Beck" with "21" on the reverse side [white, printed; reverse handwritten], " Microraphes / pygmaeus / m. / det. H. Franz" [white, handwritten and printed], " Typus " [red, handwritten] (NHMW).

Diagnosis. This is the only known species of Microraphes and can be identified on the basis of the generic characters and the aedeagus.

Redescription. Body of male ( Fig. 1 ) moderately convex, elongate and relatively slender, with moderately long appendages, BL 0.54 mm; glossy, head dark brown, pronotum, elytra and appendages yellow-brown, vestiture yellowish.

Head ( Fig. 1 ) subtrapezoidal, broadest at eyes, HL 0.09 mm, HW 0.13 mm; tempora much shorter than eyes, strongly convergent caudad; vertex and frons confluent, weakly convex and together about as long as broad; supraantennal tubercles distinct but weakly raised. Punctures on head dorsum fine and sparse, inconspicuous; setae short, sparse and suberect. Antennae slender, with indistinctly demarcated club composed of antennomeres IX–XI, AnL 0.25 mm; antennomere I elongate, II about as long as broad; III–IX each transverse; XI only slightly longer than broad, with subconical, blunt apex.

Pronotum ( Fig. 1 ) in dorsal view subrectangular, broadest near anterior fourth, PL 0.15 mm, PW 0.13 mm; anterior margin weakly and broadly arcuate; lateral margins evenly rounded in anterior half and slightly S-shaped in posterior half, nearly parallel-sided in posterior fourth; hind pronotal angles nearly right; posterior margin weakly arcuate; base of pronotum with long and distinct transverse ante-basal groove and short sub-lateral carinae. Punctures on pronotal disc fine and inconspicuous; setae on dorsal surface sparse, thin, moderately long and suberect, those on sides of pronotum ( Fig. 7 ) dense, thick and long.

Elytra ( Fig. 1 ) oval, only slightly more convex than pronotum, broadest slightly behind middle, EL 0.30 mm, EW 0.20 mm, EI 1.50; humeral calli distinct, each prolonged posteriorly by indistinct longitudinal carina as long as 1/3 EL; basal impressions shallow and short, basal fovea barely discernible; elytral apices separately rounded.

Punctures on elytral disc as fine as those on pronotum; setae short, sparse and suberect. Hind wings welldeveloped, about twice as long as elytra.

Legs ( Fig. 1 ) moderately long and slender, without modifications.

Aedeagus ( Figs. 22–23 ) stout, AeL 0.05 mm, median lobe in lateral view broadest at base and narrowing toward apex; internal armature lightly sclerotized and indistinct; parameres missing (see Remarks for the genus Microraphes ).

Female. Unknown.

Distribution ( Fig. 35 ). Northern Brasil, Amazonas State.

Remarks. In the original description Franz (1980) gives further collecting data for the holotype: the road Manaus - Itacoatiora, a forest at 220 km.

Figures

FIGURES 1 – 4. Dorsal habitus of male holotype (1 – 3) and male paratype (4). Microraphes pygmaeus Franz (1); Heteroscydmus yapacariensis Franz (2); Mimoscydmus brasiliensis Franz (3); Amimoscydmus baruerii (Franz) (4).

FIGURES 5 – 8. Morphology of Microraphes pygmaeus Franz, holotype male. Head in dorsal (5) and ventral (6) views; prothorax in ventral view (7); pterothorax in ventral view (8). Abbreviations: ai, asetose impression; ar, anterior ridge; bst, basisternal part of prosternum; cd, cardo; fr, frons; gal, galea; gen, gena; gp, gular plate; gs, gular suture; fo, foramen occipitale; hr, hypostomal ridge; hy, hypomeron; hyr, hypomeral ridge; lac, lacinia; lp, labial palp; mcp, mesocoxal projection; md, mandible; mn, mentum; mscc, mesocoxal cavity; mscs, mesocoxal socket; msff, mesofurcal fovea; msvp, mesoventral intercoxal process; mtfa, metafurcal arm; mtvp, metaventral intercoxal process; mxp, maxillary palp; nr, neck region; nss, pronotosternal suture; occ, occipital constriction; pa, posterior arm of mesoventral intercoxal process; pcc, procoxal cavity; pcs, procoxal socket; pff, profurcal fovea; pl, posterior lobe of mesocoxal projection; ppf, palpifer; pre, prepectus; pstp, prosternal intercoxal process; ptp, posterior tentorial pit; smn, submentum; tm, temple; vIII, metaventrite; vt, vertex.

FIGURES 22 – 30. Aedeagi in ventral (22, 24, 27, 28, 30), dorsal (25) and lateral (23, 26, 29) views. Microraphes pygmaeus Franz, holotype (22); Heteroscydmus yapacariensis Franz, holotype (24 – 26) and paratype (27); Mimoscydmus brasiliensis Franz, holotype (28 – 29); Amimoscydmus baruerii (Franz), holotype (30).

FIGURES 35 – 38. Distribution of revised taxa. Microraphes pygmaeus Franz (35); Heteroscydmus yapacariensis Franz (36); Mimoscydmus brasiliensis Franz (37); Amimoscydmus baruerii (Franz) (38).

FIGURES 31 – 34. Original set of labels of holotypes (31 – 33) and paratype (34). Microraphes pygmaeus Franz (31); Heteroscydmus yapacariensis Franz (32); Mimoscydmus brasiliensis Franz (33); Amimoscydmus baruerii (Franz) (34).