Lathrobium freyi Koch, 1938

Staniec, Bernard & Bordoni, Arnaldo, 2022, Comparative larval ultramorphology of three endemic Lathrobium (Glyptomerus) species (Coleoptera, Staphylinidae, Paederinae) from the Eastern Alps in Italy, Zootaxa 5175 (2), pp. 206-230 : 220-221

Lathrobium freyi Koch, 1938

Body strongly elongate, moderately flattened, relatively slightly sclerotized; head slightly (1.1×) wider than pronotum ( Figs 2, 5, 8 ). Colour: head and mandibles yellowish-brown; pronotum dark yellow with hardly visible darker posterior edge; antennae, maxillae, labium, legs, urogomphi and remaining parts of body colourless. Setae similar to those illustrated in Figs 86–90 .

Head ( Figs 11 , 16 ): almost U-shaped in outline, widening moderately from neck to anterior margin, broadest between stemmata, width ratio of neck and head between stemmata = 1:3.5; moderately flattened dorso-ventrally, about 1.2× as wide (between stemmata) as long; dorsal ecdysial lines (Es) bifurcate at about 0.25× length of head measured from anterior margin of nasale; stemmata present, ordered as in Fig. 14 . Epicranial part (E) ( Fig. 11 ) with 6 pairs of long setae (coded: Ed1–3, El1, Em2–3), a pair of glands (Gl) and a pair of pores (C1). Chaetotaxy of ventral side with 8 setae (2[V1, Vl1–3]). Apotome (Ap) not reaching tentorial pits (Tp) ( Figs 16, 19 ). Gular region as in Fig. 22 . Functional position of nasale (Na), antennae (At), mandibles (Md), maxillae (Mx), maxillary palps (Mp), labial palps (Lp) and ligula (Lg) as in Fig. 91 .

Antenna ( Figs 26, 27 ): length ratios of articles I–IV = 1:3.5:3.2:1.7. Article I almost as wide as long; article II 4.3× as long as wide, with 3 pores; article III 4.0× as long as wide, with 3 macro setae, one moderately elongate, finger-shaped and slightly curved sensory appendage (Sa), 4.8× as long as wide, growing from basal protuberance, 3 solenidia (IIIS1–3) of different lengths, and 1 pore ( Figs 26, 27 ); article IV robust, clearly club-shaped, widening strongly to apex 3.1× as long as wide, solenidia apically (IVS1–4) as in Fig. 27 ; length ratio of article IV and Sa: 1.1:1 ( Fig. 27 ). Anterior margin of nasale with 9 teeth ( Figs 32, 33 )—one small median (Mt) rounded anteriorly ( Fig. 33 ), a pair of high paramedian (Pmt) and three pairs of lateral ones (Lt1–3) ( Fig. 32 ); Lt1 tiny almost invisible, Lt3 clearly pointing outwards, the others forwards, height ratio Mt and Pmt = 1:2.2; width ratio Mt and Pmt = 1:1.3; setae of Ps1–4 nodular or peg-like ( Figs 32 , 96). Adoral surface of nasale (epipharynx) ( Fig. 38 ) with transverse row of at least 100 cuticular processes (Acp) along anterior margin of buccal cavity (Bc); pharynx (Ph) with a pair of sensilla (Sm); anterior region with indistinct, reticulate microstructure ( Fig. 39 ). Mandible ( Figs 45 , 91) falciform, moderately elongate and narrow, inner margin without any teeth. Maxilla ( Figs 49, 53 ): length ratio of cardo (Cd) and stipes (Stp) = 1:1.4; cardo 1.2× as long as wide; stipes 2.2× as long as wide; mala (Ma) short and stocky, tapering distinctly to apex, 2.9× as long as wide, with 4 long spine-shaped setae (longest seta on apex), a few tiny apical sensory appendages and 2 pores basally ( Fig. 53 ). Maxillary palp (Pm): ratios of articles I–III = 1:1.3:2.1; article I 1.2× as long as mala, 2.9× as long as wide with 2 pores apically; article II 4.2× as long as wide, widening moderately to apex, seta 1 shorter than seta 2, seta 2 located closer to base than to top; article III 9.5× as long as wide with 1 digitiform sensory appendage basally and a bunch of a few elongate sensory appendages apically ( Fig. 49 ). Labium ( Figs 56 , 106 ): dorsal side of labium (hypopharynx) slightly sclerotized on sides, central and basal portion membranous, microtrichia in anterior and central areas ( Figs 56 , 106 ). Ventral side of labium with trapezoidal prementum (Pmnt), in outline 1.2× wider anteriorly than at base ( Fig. 59 ); ligula (Lg) with long thick microtrichia, about 2.4× as long as wide, slightly separated from Pmnt by poorly sclerotized transversal strip; length ratio Lg and article I of labial palp (Lp): 1:1.4. Labial palps ( Fig. 62 ): article I 4.0× as long as wide, moderately bent in mid-section; article II bent near apex, 5.5× as long as wide, with a bunch of a few sensory appendages apically; length ratio of articles I and II = 1.7:1.

Thorax. Fore leg: length ratios of Cx, Tr, Fe, Tb, Tu = 7.6:2.5:8.6:6.5:1; Cx 3.1× as long as wide; Tr 3.1× as long as wide; Fe 7.8× as long as wide with about 40 spinose setae (about 15 tiny dorsally) and a few pores; Tb 15.0× as long as wide with 22–25 setae (9 long); Tu curved regularly, short respectively, 3.7× as long as wide, setae (coded 1, 2) unequal in length, seta 1 2.0× longer than seta 2 ( Fig. 70 ). Mid leg (only differences compared to the first pair): length ratios of Cx, Tr, Fe, Tb, Tu = 6.1:2.3:6.6:6.6:1; Cx 3.1× as long as wide; Tr 2.9× as long as wide with 7 setae and a few pores; Fe 6.8× as long as wide with about 30 setae; Tb 14.7× as long as wide with about 21 setae; Tu as in fore leg ( Fig. 70 ). Sternum with chaetotaxy as in Figs 77, 77A .

Figures

FIGURES 1-9. Mature larva, habitus. 1, 4, 7, Lathrobium alzonai; 2, 5, 8, L. L. freyi; 3, 6, 9, L. pacei.

FIGURES 86-96. Mature larva of L. alzonai (86, 88, 90, 92, 94, 95), L. freyi (87, 91, 96) and L. pacei (89, 93). 86, seta of tibia; 87-90, abdominal setae; 91, head in frontal aspect; 92, 93, median tooth; 94-96, region of paramedian tooth. Abbreviations: At—antenna, Ch—channels, Gp—glandular pit, Lg—ligula, Lp—labial palp, Ma—mala, Md—mandible, Mp—maxillary palp, Mt—median tooth, Na—nasale; Pmt—paramedian tooth, Ps—peg seta.

FIGURES 10-14. Mature larva of L. alzonai (10, 13), L. freyi (11) and L. pacei (12, 14). 10-12, head in dorsal aspect; 13, microstructure of head near dorsal ecdysial suture; 14, region of stemmata. Abbreviations: At—antenna, C—epicranial campaniform sensilla, E—epicranial part, Es—dorsal ecdysial suture; Ed—epicranialodorsal seta, El—epicranialolateral seta, Em—epicranialomarginal seta, Gl—gland, Gp—glandular pit, Md—mandible, P—posterior part/posterior seta, Trb— trichobothrium.

FIGURES 15-23. Mature larva of L. alzonai (15, 18, 21), L. freyi (16, 19, 22) and L. pacei (17, 20, 23). 15-17, half of head in ventral aspect; 18-20, apotome and tentorial region;21-23, gular region.Abbreviations:Ap—apotome,C—epicranial campaniform sensilla; Tp—tentorial pit, Trb—trichobothrium, V—ventral seta, Ves—ventral ecdysial suture, Vl—ventrolateral seta.

FIGURES 24-35. Mature larva of L. alzonai (24, 25 30, 31), L. freyi (26, 27, 32, 33) and L. pacei (28, 29, 34, 35). 24-29, left antenna (24, 26, 28) and apical section (25, 27, 29) in dorsal aspect; 30-35, anterior margin of nasale (30, 32, 34) and region of median and paramedian teeth (31, 33, 35) in dorsal aspect; Abbreviations: Lt—lateral teeth, Pmt—paramedian tooth, Ps—peg seta, Mt—median tooth, I-IV—antennal and maxillary palp articles, Sa—sensory appendage, So—solenidia.

FIGURES 36-46. Mature larva of L. alzonai (36, 37, 42-44), L. freyi (38, 39, 45) and L. pacei (40, 41, 45, 46, 46A, 46B). 36-41, epipharynx and microstructure (37, 39, 41); 42-46, right (42, 44-46) and left (43) mandible with distal portion (43, 44, 46B) and region of seta L1 (46A). Abbreviations: Acp—anterior cuticular processes, Bc—buccal cavity, Ch—channels, L1, L2—code of mandibular setae, Mt—median tooth, Pcp—posterior cuticular processes, Ph—pharynx, Pmt—paramedian tooth, Ps1—peg seta, Sm—sensillum.

FIGURES 47-54. Mature larva of L. alzonai (47, 47A, 48, 51, 52), L. freyi (49, 53) and L. pacei (50, 54). 47-54, right maxilla with stipes (48), microstructure near trichobothrium (51) and region of mala (52-54) in ventral aspect. Abbreviations: Cd— cardo, Pf—palpifer, Ma—mala, I-III—antennal and maxillary palp articles, St—stipes, Trb—trichobothrium, 1, 2—setae of maxillary palp.

FIGURES 55-63. Mature larva of L. alzonai (55, 58, 61), L. freyi (56, 59, 62) and L. pacei (57, 60, 63). 55-57, hypopharynx in dorsal aspect; 58-60, labium in ventral aspect; 61-63, left side of labial palp in ventral aspect. Abbreviations: Lg—ligula, Lp—labial palp, Pmnt—prementum.

FIGURES 97-108. Mature larva of L. alzonai (97, 99, 102-105, 107, 108), L. freyi (106) and L. pacei (98, 100, 101). 97, 98, base of mandible with microstructure; 99, 100, mandible in dorsal (99) and ventral (100) aspect; 101, micro seta (L1) of mandible; 102, mala; 103, apical section of mala; 104, apical section of stipes in dorsal aspect; 105, apical section of maxillary palp; 106, ligula in dorsal aspect; 107, microstructure of anterior region of mesonotum; 108, abdominal spiracle of pair VI. Abbreviations: Lg—ligula, Ma—mala, Mi—microtrichia, Mp—maxillary palp, Sp—spiracle, St—stipes, L1, L2—setae of mandible.

FIGURES 64-74. Mature larva of L. alzonai (64-67), L. freyi (68-70) and L. pacei (71-74). 64, 68, 71, right fore leg in anterior aspect; 65, 67, 70, 72, 74, tarsungulus of fore (65, 72) and middle (67, 70, 74) pair of legs.Abbreviations: Cx—coxa, Fe—femur, Tb—tibia, Tr—trochanter, Ts—tarsungulus.

FIGURES 75-81. Mature larva of L. pacei (75, 78, 79-81), L. freyi (76) and L. alzonai (77, 77A). 75, pronotum; 76-78, prothorax and microstructure of lateral region (77A); 79, thoracic tergite III and abdominal tergite I; 80, abdominal tergite II; 81, abdominal segments IX and X in dorsal view. Abbreviations: A—anterior seta, Ap—posterior pore, D—discal setae of rows a and b, L—lateral seta, P—posterior seta, Pr—presternum, Te—tergite, Tg—tergal gland, Sp—spiracle, Stp—sternum, Ug—urogomphus.