taxonID	type	description	language	source
FD2D8785FF8AFFA4FCE0C05EFC9BF97A.taxon	description	Oxelytrum cayennense (Sturm, 1826) Eggs (n = 77) (Figs. 2 A – D) Maximum width: 1.00 – 1.82 mm (mean 1.33 mm). Eggs laid individually or in clusters on the soil surface, in variable quantities (31.44 ± 26.7 eggs); protected by a thin transparent membrane (Figs. 2 A and B). Eggs are oval-shaped, varying from white to yellowish white chorion with wrinkled carvings (Figs. 2 C and D); micropyle not visualized. First instar (L 1) larva (n = 41) (Figs. 3 A – C, 4 A – G, 5 A – B, 6, 7 and 8 A – B) Body length: 5.09 – 8.87 mm (mean 7.24 mm); head width (between dorsal stemmata): 0.76 – 1.44 mm (mean 1.13 mm); pronotum width: 2.10 – 3.68 mm (mean 2.67 mm). Campodeiform, narrowing towards both ends, widest at metathorax, flattened dorsoventrally. General color: dorsal region predominantly brown, lateral expansions varying from white to light yellow, each one bearing a posterolateral seta; medial line thin and yellow on thoracic terga (Fig. 3 A); ventrally, thorax predominantly membranous and white; abdominal sterna brown, shade slightly lighter than that of terga (Figs. 3 B and C). Dorsal and ventral surfaces dull. Terga with regular isodiametric microsculpture on posterior margin, except absent in nineth segment and the pronotum with microsculpture on anterior and posterior margin. Head capsule. Prognathous, narrower than the pronotum, dark brown, heavily sclerotized. Coronal suture short; frontal branches in an open-U shape, extending until inner lateral margin of antenna sockets; epistomal suture interrupted at medial region (Fig. 4 A). Three pairs of stemmata on each side: two dorsal pairs above antennal level, one pair below antennal level (Fig. 4 B). Three antennomeres (Figs. 3 A, B, 4 B, D, E and G), first antennomere wider and slightly shorter than others, bearing many small setae; second antennomere narrower at the base with three subapical setae (Figs. 4 A: A 1, A 2, A 3) and inner lateral lobe with small sensillar cone (arrow in Fig. 4 G); third antennomere white, narrower than others, with many setae (Figs. 3 A, B and 4 G) and three microchaetae at apex (Fig. 4 F). Clypeus sub-trapezoidal, short, with four pairs of setae (Fig. 4 A): one anterior pair (C 1), one anterolateral pair (C 2), one lateral pair (C 3) and one pair on medial region (C 4). Labrum free, sub-rectangular, formed by three distinct sclerites; medial anterior sclerites larger than others, bearing two pairs of setae, one internal and short (Lb 1) and one anterolateral long (Lb 2) (Fig. 4 A); medial posterior sclerite bifid, without setae and a lateral sclerites with one pair of setae each, internal setae (Lb 3) longer than external (Lb 4) (Fig. 4 A). Mandible strong, prominent, mobile, sub-symmetrical, apex bifurcate, apical tooth about 2 X longer than sub-apical tooth, inner margin of apical tooth with nine denticuli (Fig. 4 C), with one pair of setae arising from each side (Fig. 4 A): one anterolateral and short (M 1), one internal and long (M 2), inner margin of sub-apical tooth without denticuli. Maxilla (Fig. 5) mobile, cardo (CA) broad, with one lateral seta near apex (arrow); stipes (ST) as long as wide, tapering apically, with four setae in outer margin, one in inner margin and one pore in inner margin; lacinia and galea basally fused, separated only apically. Galea (GL) with sclerotized base, apex membranous, sub-rounded with several brush-like setae; lacinia with nine spike-like setae on inner lateral surface, elongate apically, apex shorter than galea. Maxillary and labial palpomeres without basiconical sensillae at apex; maxillary palpomeres (MP) trimerous, first segment as long as second, which bears three setae, third segment slenderer, longer than second, tapering distally, covered with several minute setae. Labium, submentum (SM) and mentum (ME) fused, submentum tapering gradually towards apex, less sclerotized in distal and basolateral regions, with setae of different lengths and one pore on each side at mid-length (arrow in Fig. 5); mentum sub-rectangular, about 2 X wider than long, wider than base of prementum (PME), more sclerotized at the base, with one pair of long setae at mid-length, one basal pair shorter, clearly more inconspicuous – and one pore located laterally between shorter and longer setae (arrow in Fig. 5); prementum short and bearing one setae on each side near apex (arrow in Fig. 5). Labial palpomeres (LP) dimerous, distal segment conical, narrower and greatly shorter than proximal, about half length of basal segment, bearing basiconical sensillae in distal region (Figs. 5, 6). Ligula (LG) bilobed, heart-shaped and membranous, covered ventrally by fine short setation on the two lobes (Fig. 5). Epipharynx with one pair of anterolateral spine-like setae, below of labial palp (SS, Fig. 6) and one pair of anteromedial spatula-shaped setae; two pairs of medial pores, two longitudinal areas covered by microchaetae; gula and gular sutures absent. Thorax, pronotum narrower but longer than meso- and metanotum (Fig. 3 A). Pleuron with one elliptical spiracle on intersegment of mesothorax (arrow in Fig. 3 C), twice length of abdominal spiracles (Fig. 3 C). Prosternum (Figs. 3 B and 4 E) with three small and sclerotized plates on anterior region, medial plate trapezoid - shape, larger than others, lateral plates subtriangular; intercoxal region with several short setae. Legs (Fig. 7) pentamerous, diameter decreasing towards apex; femora and tibiae longer than other segments; coxae, trochanters, femora and tibiae bearing bunches of setae; trochanters and femora with two ventral rows of short and strong spines; a single seta longer than spikes between rows, at mid-length; tarsungulus with one pair of setae (Fig. 7). Abdomen (Figs. 3 A and B) with 10 segments visible in dorsal view, tapering towards apex, with lateral expansions projecting posteriorly in distal segments. Terga 1 – 9 light brown, brown shade, becoming lighter towards distal region. Sternum 1 divided into three weakly sclerotized sternites, one medial and two lateral. Sternum 2 with three sclerotized sternites, one medial sternite larger than two lateral combined (described above). Sterna 3 – 8 large and highly sclerotized, not reaching terga. Abdominal pleura 1 – 8 containing a rounded spiracle each (Fig. 3 C). Segment 9 with a pair of apical dimerous urogomphi, basal segment wider, light brown and 1.5 x longer than distal one (arrow in Fig. 8), bearing 4 – 5 setae distally. Sternum 9 joint with respective tergum laterally (Fig. 3 C). Segment 10 tubular without lateral projections, with a circular anal opening (arrow in Fig. 8 A), several setae arising from segment apex, a pair of longer setae dorsally located (arrow inFig. 8 B). All sternites with a row of setae in posterior margin. Second instar (L 2) larva of Oxelytrum cayennense (n = 51) (Figs. 9 A – C and 10 A – D) Body length: 8.72 – 14.78 mm (mean 10.64 mm); head width (between dorsal stemmata): 1.06 – 1.79 mm (mean 1.37 mm); pronotum width: 3.01 – 3.89 mm (mean 3.38 mm). General color: dorsal region predominantly light brown, with a pale medial line, extending to the last abdomen segment, becoming evanescent towards the last tergite, more evident than L 1. Lateral expansions present, increased compared to L 1, varying from white to light yellow (Fig. 9 A); Head light brown; tergites 1 - 9 light yellow with lateral whitish; maxillary and labial palpomeres with basiconical sensillae at apex (Figs. 10 A – C). A pair of micro setae between dorsal stemmata (Fig. 10 D). Basal segment of urogomphus light brown, approximately three times as long as distal. Remaining characters as in L 1. Third instar (L 3) larva of Oxelytrum cayennense (n = 32) (Figs. 11 A – C, 12 A – D and 13 A – F) L 3 (Figs. 11, 12 and 13). Body length: 19.0 – 22.6 mm (mean 16.70 mm); head width (between dorsal stemmata): 1.03 – 2.55 mm (mean 1.98 mm); pronotum width: 4.00 – 5.00 mm (mean 4.53 mm). General color: dorsal region predominantly dark brown (Figs. 11 A and C), with lateral expansions increased compared to L 2, varying from white to light yellow only on the anterolateral half; sometimes yellow colored on head (Fig. 12 A) and on segments 9 and 10; a longitudinal medial yellowish line extending from pronotum to tergum 9, wider than in previous instars (Fig. 11 A). Maxillary and labial palpomeres without basiconical sensillae at apex; Labial palpomeres dimerous and maxillary palpomeres trimerous (Fig. 12 B). Prosternum sclerotized, meso- and metasternum with sclerotized punctures (Fig. 11 B). Thoracic spiracle elliptical (Fig. 13 B), about twice as large as rounded abdominal spiracles (Fig. 13 E). Abdominal sterna yellowish-brown with conspicuous sclerotized punctures (Fig. 11 B). Urogomphi with proximal segment dark brown, three times as long as distal one (Fig. 12 C and D). Segment 10 bearing spine-like setae, dorsal pair distinctively longer (Fig. 13 F). Characteristics observed through SEM, only observed in L 3: Thoracic and abdominal terga with setae short on lateral margin (Fig. 13 C and D); abdominal sterna with several short slender setae (Figs. 13 C and D). Remaining characters as in L 1 and L 2. Pupa of Oxelytrum cayennense (n = 16) (Figs. 14 A – C, 15 A – F and 16 A – F) Body length: 13.0 – 20.0 mm (mean 16.5 mm). Adectica exarate, white-colored (Fig. 14 A – C). Pronotum: width = 4 – 6 mm, wider than other tergites; four long plain setae on anterior margin (Fig. 14 B and 15 A); short setae conglobate on lateral margin; fewer setae on posterior region (Fig. 14 A); tergites 1 - 2 with anterior and posterior wings, respectively. Abdomen: Segments 2 – 8 each with a pair of long, lateral setae (Fig. 15 E), about 2.12 mm long; segment 9 with a pair of urogomphi (Fig. 16 F), as long as abdominal setae; segment 10 with a pair of short setae (Fig. 16 F). Pleura, abdominal segments 1 – 5 (Fig. 14 A) with a pair of functional spiracles ringshaped, anterior-most four heavily sclerotized; segments 6 – 8 with vestigial spiracles; segments 1 – 3 bearing dorsolateral sclerotized regions, rounded, which are more sclerotized on segment 1 and 2 (Fig. 14 C).	en	Hummig-Neto, Eurico, Rafael, José Albertino, Ferreira-Keppler, Ruth Leila, Barros, Luana Machado (2025): Taxonomy of the immature stages of Oxelytrum cayennense (Sturm, 1826) (Coleoptera: Staphylinidae: Silphinae) of forensic importance from Central Amazon, Amazonas, Brazil. Revista Brasileira de Entomologia (e 20250014) 69 (3): 1-19, DOI: 10.1590/1806-9665-RBENT-2025-0014, URL: https://doi.org/10.1590/1806-9665-rbent-2025-0014
FD2D8785FF8AFFA4FCE0C05EFC9BF97A.taxon	discussion	Remarks: In general, the characteristics that vary between the larval stages of O. cayennense are related to coloration, urogomphi and body length (Fig. 17). The lateral expansions are whitish in the first and second instar (Fig. 17 E and F), while the third instar is whitish only in an interior margin, posterior margin brown (Fig. 17 G). The medial line is thin, conspicuous only in the thoracic segments in the first instar (Fig. 17 E), in second instar is thin, conspicuous in all body segments (Fig. 17 F), while in third instar is wide and conspicuous in all body segments (Fig. 17 G). The head color is dark brown in the first instar (Fig. 17 A and E), light brown in second instar (Fig. 17 B and F) and yellow in third instar (Fig. 17 C and G). The basal segment of urogomphus is light brown and 1.5 x longer than distal one in first instar, in second instar the basal segment is light brown and 3 x longer than distal, while in third instar is dark brown and 3 x longer than distal segment. The body measurement varies between the instars: in first instar varies 5.09 – 8.87 mm, in second instar varies 8.72 – 14.78 mm and in third instar varies 19.00 – 22.6 mm. The pupa (Figs. 17 D and H) presents adult structures perceptible in pharate imago: compound eyes and clavate antennae (Figs. 14 A and 16 B), wings (Figs. 14 A and 15 D), legs with pentamerous tarsi and tarsal claws (Figs. 14 A and 16 D). Analyzing the pupae of O. cayennense and O. discicolle it is possible to notice some changes in relation to the larval stage, such as: differences in color, since the pupae has a light color, from yellow to whitish, while the larvae are light to dark brown; it is possible to observe structures in the pupae that belong to the pharate adult, such as the formation of two extensions on the thorax that correspond to the wings, in addition to the modification in the tarsomeres, which in the adult are divided into five segments. Despite the similarities, the pupa of O. discicolle differs from O. cayennense by the remake in the outer bristle of the anterior region of the pronotum, which is bifid at the apex, while in O. cayennense the bristles are plain.	en	Hummig-Neto, Eurico, Rafael, José Albertino, Ferreira-Keppler, Ruth Leila, Barros, Luana Machado (2025): Taxonomy of the immature stages of Oxelytrum cayennense (Sturm, 1826) (Coleoptera: Staphylinidae: Silphinae) of forensic importance from Central Amazon, Amazonas, Brazil. Revista Brasileira de Entomologia (e 20250014) 69 (3): 1-19, DOI: 10.1590/1806-9665-RBENT-2025-0014, URL: https://doi.org/10.1590/1806-9665-rbent-2025-0014
