Amphientomum knorrei Weingardt, Bock & Boudinot, 2024

Boudinot, Brendon E., Bock, Bernhard L., Weingardt, Michael, Troeger, Daniel, Batelka, Jan, LI, Di, Richter, Adrian, Pohl, Hans, Moosdorf, Olivia T. D., Jandausch, Kenny, Hammel, Joerg U. & Beutel, Rolf G., 2024, Et latet et lucet: Discoveries from the Phyletisches Museum amber and copal collection in Jena, Germany, Deutsche Entomologische Zeitschrift 71 (1), pp. 111-176 : 111

‡ Amphientomum knorrei Weingardt, Bock & Boudinot sp. nov.

Etymology.

We dedicate this species to Dietrich von Knorre, whose lifework was to establish and curate the collection of the Phyletisches Museum. Besides being a natural conservationist and a dedicated teacher of students, von Knorre was the curator of the Museum from 1969 till 2003, during which time he dealt with nearly every item in the entire collection. In addition to his more than 270 publications ( Köhler 2019), he has done meticulous research on the history of an immense number of objects and has become the museum’s "living archive". With the newly discovered specimen bearing his name, we want to express our gratitude for his continuous support and contributions to the Phyletisches Museum.

Type materials.

Holotype. PMJ Pa 5809, Copal (East African?). Female. Interactive cybertype: Appendix 1: Fig. A3 .

Paratypes. None.

Diagnosis.

Macropterous. Wings and body covered with scales. Scales apically straight or medially incised. Epistomal sulcus complete and corresponding epistomal ridge wide. Genae long. Vertex narrow and rounded. Three ocelli of similar size present, forming an isosceles triangle. Lateral ocelli closer to each other than to compound eyes. Compound eyes large and their upper margin reaching uppermost margin of vertex. Antenna with 15 articles. Flagellomeres with secondary annulation. Maxillary palps with four articles, a minute basal article and a long and cylindrical last palpomere that is rounded distally. No conical sensillum visible on second maxillary article. Tip of lacinia with long lateral region bearing several rounded denticles, and a shorter truncated median tine. Water-vapor absorption-apparatus on hypopharynx present. Labial palps with 2 articles, the basal one short and small, the distal one large, round and flattened. Pronotum strongly reduced, barely visible dorsally as mesonotum exceeds its height. All tarsi with 3 articles. First tarsomere of hind leg very long, with 24 ventral ctenidiobothria. Claws with 1 minute preapical tooth and small ventral subapical microtrichia. Pulvilli absent. Metacoxal interlocking mechanism present. Profemur with at least 27 small spines. Tibiae with horizontal rings of brown scales. Protibia equipped with only 1 distinct apical spur. Mesotibia with 3 long apical spurs. Metatibia with 6 (3 long and 3 short) apical spurs. Unique scale patterning on forewing present, differentiating it from related species. Anteroproximal region of forewing densely covered with dark brown scales. Distal part of Sc in forewing present, closing pterostigma proximally. Rs and M connected by cross vein in forewing. Areola postica of triangular shape and distinctly longer than high. CuP and A1 do not fuse at forewing margin. Tip of R1 vein of hindwing reaching anterior wing margin. Proximal section of Rs in hindwing absent, basiradial cell open. Hindwing with simple M vein. Conspicuous color patterning on abdomen with pale spots on darker brown patches. Clunium unmodified. Epiproct and paraproct simple, the latter with inconspicuous sensorium. Subgenital plate simple and rounded apically with long setae. T-shaped sclerite not visible. Valvulae largely hidden by subgenital plate, but all three pairs present and external valve bilobed.

Description.

Measurements (in mm): Body length: 3.7. Head length: 1.4 (labrum-vertex). Head width: 1.2 (between compound eyes). Length of antennae: 2.21. Length of scape: 0.10. Length of pedicel: 0.10. Length of flagellomeres: f1 = 0.29, f2 = 0.27, f3 = 0.23, f4 = 0.26, f5 = 0.18, f6 = 0.15, f7 = 0.11, f8 = 0.12, f9 = 0.09, f10 = 0.10, f11 = 0.06, f12 = 0.09, f13 = 0.07. Length of maxillary palpomeres: I = 0.06, II = 0.24, III = 0.14, IV = 0.22. Length of thorax: 0.90. Length of forewings: 3.9. Width of forewings: 1.4 (largest width). Length of hindwings: 2.8. Width of hindwings: 1.0. Length of hindlegs: F = 0.93, T = 1.54, t1 = 1.03, t2 = 0.15, t3 = 0.15. Length of abdomen: 2.2. Length of subgenital plate: 0.78. Length of epiproct: 0.24. Length of paraproct: 0.3.

Note. Different measurements based on photos or renders result from the strong curvature of different body parts. Therefore, we used the 3D reconstructions for most measurements and the photos for measuring the length of metatarsomeres and the forewing.

Indices (measured from dorsal, after Lienhard 1998): IO/D: 1.21. PO/D: 0.73.

Coloration. Head capsule dark brown. Postclypeus with few small darker spots. Labrum brown, slightly darker than rest of head. Antennal flagellum light brown to middle brown, becoming brighter distally. Maxillary palpomeres dark brown with apical regions of articles 2 and 3 lighter in coloration. Labial palpomeres light brown with dark spot on central area of flattened surface of palpomere 2. Compound eyes light brown, with darker circular areas of pigmentation. Ocelli dark brown, but median ocellus slightly brighter. Thorax slightly darker in color than head. Legs brown, less strongly pigmented apically. Forewing membrane of light brown tone, brighter towards apex. Hindwing almost hyaline, slightly more yellowish to brownish towards base. Wing veins in light brown to brownish tone or almost hyaline. Abdomen with conspicuous pattern of pale ocher patches surrounded by dark brown areas. Subgenital plate nearly uniformly dark brown, but lateral base paler. Ovipositor valves light brow with slight yellowish tint. Scales light brown to dark brown, with tips generally darker than base. Color patterns of head, compound eyes and abdomen possibly faded and with artifacts, due to non-ideal preservation in resin and subsequent suboptimal storage.

Head capsule. The head is distinctly higher than wide and anteroposteriorly flattened, thus appearing almost scale shaped. In dorsal view it appears wider than long. The vertex (Figs 5A , 6B , 7A , ve) is narrow and rounded, while the frontal area is relatively large (Figs 5A , 6A , 7A, B , fr). In frontal view, the dorsal margin of the vertex is almost straight with only a very slight concave impression laterad the median line. Three ocelli (Fig. 6A , oc) are placed flat on the frons and vertex without a cuticular elevation, closer to each other than the lateral ocelli to the compound eyes. The median ocellus is slightly smaller than the lateral ones. The ovoid and relatively large compound eyes are not extending over the upper margin of the head, with a wide distance between them. The circumocular ridge (Figs 8A, B , 9 , cor) is well-developed and wide, forming an oval that is slightly curved inwards on its posterior side. Externally, a conspicuous coronal sulcus (Fig. 6B , cs) is discernable, corresponding with the well-developed internal median coronal ridge (Figs 8B , 9 , cr). The frontal sutures are present but indistinct. The external epistomal sulcus (Figs 5A , 6A , 7A, B , 10A , eps) is complete and semi-oval, with the postclypeus (Figs 5A , 6A , 7A, B , 10A , pcl) extending ventrally over the ventral genal margin. The large postclypeus is not strongly convex or bulging but rather scale-like. It is approximately twice as long as the frons. Two slit-like impressions begin on the ventral end of the postclypeus slightly laterad the midline and run in an acute angle approximately towards the postclypeal midlength where they obliterate. The internal epistomal ridge (Figs 8A, B , 9 , epr) is wide (epistomal ridge in sagittal section longer than half of the length of the entire postclypeus, Fig. 8A, B ). The anteclypeus (Figs 6A , 7A, B , 10A , acl) is relatively small and more than 4 times as wide as long, wider proximally than the ventral margin of the postclypeus and enveloping parts of it. The anterior tentorial pits (Fig. 7A, B , atp) are visible directly at the ventral margin of the epistomal ridge, almost adjacent to the anterior mandibular articulation. The posterior tentorial pits dorsad the insertion of the maxillary stipes to the head capsule are slit-like (visible in µCT scan). The well-developed tentorium is composed of large anterior (Figs 9 , 11I , ata) and posterior arms (Figs 9 , 11I , pta), a narrow corpotentorium (Figs 9 , 11I , ct) and thin dorsal arms (Figs 9 , 11I , dta). The anterior arms are anteriorly twisted and do not fuse with each other posteriorly. The very thin dorsal arms are not entirely preserved. The right dorsal arm is ending before it reaches the antennal insertion, while the left arm is almost completely missing in the specimen. The corpotentorium is compact and short and the posterior arms straight and thick. A well-developed postoccipital ridge (Fig. 9 , por) and external postocciput form the posteriormost cephalic region. The head is posteriorly open, i.e., no genal-, hypostomal- or postgenal bridge or gula is developed but the posteroventral closure of the head is formed by the weakly sclerotized postmentum (Fig. 9 , pom).

Head appendages. The lobe-shaped labrum (Figs 6A , 7A, B , 10B , 11A, B , lb) is approximately 2-times as wide as long and covered with long setae (likely sensilla) (Fig. 10B ). It is narrower at its base and apex and widest at about midlength. A median notch is missing, and the distal margin evenly rounded. The labral nodes are absent and epipharyngeal sensilla are not visible. A median transverse epipharyngeal fold (Fig. 11B , eptf) is present on the middle region of the epipharynx. The antennal insertions are located in a fovea (Fig. 7A, B , gef), which partly separates the genal region from the frontal region. The genal area is almost twice as long as the frontal area. The internal genal ridge below the fovea is straight (Figs 8A , 9 , ger) and increases in thickness posteriorly. It starts shortly behind the posterior end of the ridge enclosing the antennal foramen and ends at the posterior genal region. It corresponds externally with the straight genal sulcus (Fig. 7A, B , ges). The antennae have 15 articles. The barrel-shaped scape and pedicel are approximately as long as wide. All flagellomeres display a secondary annulation (Fig. 5F ). The last flagellomere is relatively short and pointed apically. The entire flagellum is very thin and thread-like, with the flagellomeres approximately 1/3 as wide as the pedicellus. The setae on the flagellum are long and thin, slightly thicker and longer on the lateral surface compared to the medial side. The basal portion of the flagellomeres is only faintly differentiated (Fig. 5F ), and a proper collar is not developed (see Seeger 1975). The mandibles (Figs 7A, B , 9 , 11C, D , md) are subtriangular with similar lengths of the mesal and lateral edges. They are not elongated and of the "outer margin rounded, and posterior margin not hollowed" type ( Yoshizawa 2002). The lateral edge is convex over its entire length. The molar region (Fig. 11C, D , mo) is asymmetric, with a distal molar tooth (Fig. 11C, D , mot) on the left mandible. The right mandible has a proximal tooth-like extension (Fig. 11C, D , pmdt). The inner mandibular rim has no distinct features differentiating it from mandibles of other psocids. It is thickest on its median side and becomes narrower laterad. The lateral side of the mandibular rim between the posterior condyle (Fig. 11C, D , pcmd) and anterior socket (Fig. 11C, D , asmd) (primary and secondary mandibular joints) widens. Two apical teeth (incisivi) are present, the apical one (Fig. 11C, D , inc1) longer and wider than the subapical one (Fig. 11D , inc2). Slightly proximad of the incisivi a blade-like projection is present, a convex cutting edge (Fig. 11C, D , mdce). A postmola is not discernible. The apodeme of the mandibular adductor (Fig. 9 , amdad), at least partially preserved, inserts on the medial base of mandible. The maxilla lacks a cardo. The stipes (Fig. 7B , st) is oval and represents the main body of the maxilla, together with the apical palpifer (Fig. 7B , ppf). The galeae (Fig. 7A, B , ga) are relatively flat and located between the mandibular concavity anteriorly and the hypopharynx posteriorly (visible in µCT-scan). The tip of the lacinia (Figs 11F , 12I , lc) is long and bears several rounded denticles. It is bent laterad apically. The inner tine is short and bent slightly inwards distally. The outer tine is distinctly longer and higher. The lacinial gland is not preserved or not present. The maxillary palps (Figs 6A , 11E , mxp) consist of four articles. The second article is the longest, ca. 1.3 times as long as the fourth and ca. 2 times as long as the third. The first article is extremely short and only ¼ as long as the third. Several long setae (likely sensilla) are located on each palpomere except for the glabrous first one. The second maxillary palpomere lacks a conical sensillum. The fourth palpomere is conical and has a rounded apex. The hypopharynx (Fig. 9 , hy) is equipped with the anterior sitophore (Figs 9 , 11G , sit) and the paired posterior salivary sclerites (Figs 9 , 11H , sas). A triangular median extension of the sitophore (Fig. 11G , mesit) is present proximad the mortar, which is (Fig. 11G , mor) is oval and embedded in the sitophore like in a sclerotized block. The oral arms of the sitophore are present but indistinct in the µCT-scan. The paired salivary sclerites are lateral elements of the posterior hypopharynx, ovoid and bowl-shaped. They bear a long apodeme (Fig. 11H , asas) which is long and curved inwards at its internalmost apex. A furrow runs longitudinally (Fig. 11H , lfsas) across each salivary sclerite. The tubular filaments between the sitophore and salivary sclerites are not visible (a resolution of 2 µm is not sufficient for visualizing the very thin tubular filaments, which have a diameter of ca. 3 µm in a large psocid ( von Kéler 1966) and connect the longitudinal furrow of the posterior salivary sclerites with the anterior hypopharyngeal mortar), but are likely developed, as the water-vapor absorption apparatus functionally depends on their presence. The labium is composed of a thin-walled and weakly sclerotized postmentum (Fig. 9 , pom) and a thicker-walled prementum (Fig. 9 , prm). A median furrow separates symmetrical premental halves (see Fig. 11J ). The labial palps (Fig. 11J , lap) have two articles. Palpomere 1 (Fig. 11 , lap1) is short and narrow, and palpomere 2 (Fig. 11 , lap2) plate-like, large and rounded, and displays a darkly pigmented field. The second palpomere bears many long setae (likely sensilla), that are concentrated on the margin. The short and rounded paraglossae (Figs 6A , 11J , pgl) are inserted between the palps. The glossae (Figs 6A , 11J , gl) are probably represented by lobe-shaped structures, almost fused medially, with only a faint medial dividing line. Remnants of soft tissue are visible in the head, which are likely vestiges of the central nervous system, retinulae and possibly the mandibular adductor muscle, as well as other cephalic muscles.

Thorax. The cervical region is not exposed. The laterocervical sclerite is indistinctly visible as a thin bar-shaped sclerite, but scarcely discernible from the cervical membrane in the renders. The prothorax is strongly reduced. The pronotum (Fig. 8A, B , prn) is very short and bar-shaped, and the propleurae (Appendix 1: Fig. A3 ) are continuous with it laterally. The relatively large episternum is located dorsad the small preepisternum (Appendix 1: Fig. A3 ) and separated from it by an external furrow (Appendix 1: Fig. A3 ). The mesothorax exceeds the height of the pronotum (Figs 6B , 7A, B , 8A, B ). The mesonotum (Figs 6B , 7A, B , 9A, B ) is strongly enlarged and dorsally densely covered with scales (Figs 5A , 6B ). A prophragma is not developed or extremely reduced. The mesonotum consists of an anterior semicircular part of the scutum, larger paired lateral scutal lobes, and a posterior triangular scutellum (Fig. 6B ). The anterior scutal portion is separated from the lateral lobes by the lateral parapsidial sulci (Fig. 6B ), which correspond with internal parapsidial ridges (Fig. 8A, B , parr). The postnotum is located posteroventrad the scutellum as a bar-shaped short sclerite (Fig. 6B ). The mesophragma (Fig. 8A, B , msp) is wide and strongly developed. The scutoscutellar suture (Fig. 6B ) is present, albeit somewhat weakly developed. The metathorax is distinctly shorter than the mesothorax. The anterior and lateral lobes of the scutum are not separated by an external furrow, whereas a distinct scutoscutellar line delimits the small, rounded scutellum. The metaphragma (Fig. 8A, B , mtp) is wide but smaller than the mesophragma. As the pleural elements of the specimen appear asymmetric on both sides and as there are many artifacts in the 3D-model, we will not describe this thoracic region in detail. The external sternal elements of each thoracic segment are not discernible from surrounding membranous regions. The profurcae (Fig. 8A, B , prf) are only indistinctly recognizable, whereas the meso- and metafurcae (Fig. 8A, B , msf, mtf) are distinctly visible as distally widened and flattened arms. Spinae of the meso- and metathorax are absent. The three pairs of coxae are adjacent medially. The profemur bears at least 27 ventral spines (Fig. 10C ). The protibia bears one, and the mesotibia three apical spurs. The metatibia displays three short and three long apical spurs. All tarsi are 3-segmented. Metatarsomere 1 bears 24 ctenidiobothria (Fig. 5E ). Tarsomere 1 of the foreleg and hindleg are almost 3 times as long as the respective tarsomeres 2 and 3 combined. The very long metarsomere 1 reaches ca. ¾ of the length of the metatibia. Mesotarsomere 1 is approximately twice as long as mesotarsomeres 2 and 3 combined. Two apical ventral spurs are inserted on tarsomeres 1 and 2 of each pair of legs. The symmetrical claws are equipped with a single small preapical tooth (Fig. 5D ) and several ventral microtrichia proximad this structure. Pulvilli are absent. The mirror and rasp substructures of the Pearman’s organ are absent. A distinct ball-shaped cuticular projection (Fig. 12A, B , hcp) on the inner side of the left metacoxa is visible, fitting with a cup-shaped emargination (Fig. 12A, B , hce) on the inner side of the right metacoxa. The legs, especially the femora and tibiae, are densely covered with scales. Several closely placed somewhat irregular rings of these surface structures are inserted on the metafemur (Fig. 5C ).

Forewing. Wing with three types of scales. First type long, parallel-sided, straight and with a straight apex (Fig. 5H ). Second type long (slightly to distinctly shorter than type one), parallel-sided to subparallel and straight, emarginate with a median notch (Fig. 5H ). Third type short, broad, parallel-sided from 2/5 to apex of scale, and converging in the basal 1/5, with a straight and finely frayed apex (Fig. 5G ). The wing scales display a longitudinal striation except for type I where this is not visible. The scale patterning is very distinct, with an increased density at the wing base, differentiating it from related species (Figs 5A, B ). The proximal Sc vein is very short and ends freely in the wing membrane. A line of dark scales follows approximately this vein. R1 merges at 2/3 of the wing length with the anterior margin. A short and anteriorly bent distal Sc vein closes the pterostigma. This triangular cell displays a strongly acute angle between Sc and R1 and is wide (600 µm) but very low (110 µm). The base of Rs forms an obtuse angle with the distal portion of this vein. The basal vein of Rs is almost transparent, and dorsally bears a patch of dark scales. The veins R2+3 and R4+5 are convex almost over their whole length, and M1 is curved distally. M2 is almost straight. M3 is concave distally. The origins of all three M veins are placed close to each other, almost forming a fork. The specimen displays a slight asymmetry in the base of the three M veins. On the right forewing, they originate from a common stem, while M1+M2 are connected in left one but both separated from the base of M3. A conspicuous acuminate lobe is present between M1 and M2, and a short cross vein between Rs and M (90 µm). The areola postica is relatively wide and low and forms a triangle with an acute angle between CuA1 and CuA2. CuP and A1 join the posterior wing margin at a distance from each other (Fig. 10D ). The course of the very faint vein A1 is almost invisible due to the coupling of the fore- and hindwing on both sides. The vein A2 is indistinct.

Hindwing. Type I and II scales are present (Fig. 5H ). No closed cell is present in the hindwing (Figs 5A, B ). R1 and CuA are ending at approximately 2/3 of the total wing length, the former on the anterior margin and the latter on the posterior margin. Only one M vein is present. The common veins R2+3 and R4+5 are slightly shorter than half the length of M. R2+3 end anteriorly on the margin in the last 1/5 of the wing length. R4+5 ends almost directly on the wing apex, and M almost at the same length as R2+3 but on the posterior margin. Rs is bent anteriorly where it forms a cross vein with R1 in other Amphientomum species, but any trace of this cross vein is lacking. CuA is curved at its distal end. The distance between CuA and CuP is approximately equivalent with the length of Rs. A1 is curved and ends on the basal posterior wing margin. The margin of the apical half is covered with long scales and setae, the latter more densely anteriorly.

Abdomen. The abdomen is strongly bent towards the thorax (Figs 5A, B , 7A, B ). The external segmentation of the abdomen is only partially visible, as some segmental borders are very faint or deformed as an artefact. However, it seems to follow the general pattern in Psocodea ( Badonnel 1934) without any conspicuous modifications. The clunium (Fig. 10E , clu), the epiproct (Figs 8B , 10E , epp) and the paraproct (Figs 8B , 10E , pap) are unmodified, the latter covered with long setae and bearing an indistinct sensorium. The apex of the subgenital plate is simple and covered by long setae. The subgenital plate largely covers the ovipositor valves, thus only the tips are exposed (Figs 5B , 6C , 7C ). The external valve (Fig. 10F , exv) is bilobed, the dorsal portion wider but not as long as the ventral portion, which is pointed apically. The dorsal valve (Figs 7C , 10F , dov) is almost tubular and apically rounded. The ventral valve (Fig. 10F , vev) is barely discernible but present as an elongated tube.

Remarks.

" Die Art und Weise der Lagerung und Erhaltung der Stücke im Bernstein erlaubt den Schluß, daß diese Art wesentlich wilder und beweglicher gewesen sei als die übrigen Psocen, dabei aber zugleich weniger derb gebaut. Daß bei den sichtlich starken Anstrengungen der Thiere, dem Harz zu entgehen, das Schuppenkleid oft stark abgerieben wurde, ist leicht begreiflich und durch mitunter massenhaft danebenliegende Schuppen bewiesen. Aber auch die Endglieder der Fühler sind mitunter beim Vordrängen des Thieres abgetrennt, und die obere Membran der Flügel ist zuweilen von der offenbar fester dem Harz anhängenden unteren Membran getrennt, und beim Vordrängen des Thieres in regelmäßige kleine Querfalten gebracht. " - Hermann Hagen’s (1882) commentary about the preservation of Amphientomum specimens in Baltic amber.

‡ Amphientomum knorrei Weingardt, Bock & Boudinot, sp. nov. ( Troctomorpha : Amphientometae : Amphientomidae ) represents the first record of this family and genus in East African copal (14C date: ~390 ± 13 years old) and may still be extant in East Africa. The genus Amphientomum is known from the lowermost Eocene amber of Oise in France and is at least 56.0-47.8 Mya ( Nel et al. 2005) old. In total, 20 species are described including the new one presented here (Table 5 ). Today they occur in countries of Western (Ivory Coast, Nigeria), Central (Angola, Republic of the Congo) and Eastern Africa (Madagascar, Tanzania) ( Lienhard 2016; Johnson et al. 2023), and one additional species is described from China ( Li 1999, 2002). Four species are known from the fossil record, two, as previously listed, were described by Enderlein (1905), and one by Pictet (1854) from Baltic amber. Additionally, one species was described from French Eocene Oise amber by Nel et al. (2005). The subfossil described here is a female, as the subgenital plate and the apical tips of the valvulae are visible. It differs from all other described species of Amphientomum by its characteristic forewing scale pattern.

Only one species has been assigned to Amphientomum outside of Africa and Eurasia, Am. indentatum Turner, 1975, from an extant population in Jamaica. However, this species is definitely misplaced, as several features of it are not compatible with the currently accepted diagnostic character repertoire of Amphientomum (see Taylor 2013 for an identification key of the genera of Amphientomidae ), i.e., the lateral ocelli are widely spaced and close to the compound eyes, and the hind wing vein R1 does not reach the wing margin. Given these characters, the species in fact matches with Lithoseopsis Mockford, 1993 ( Mockford 1993; Taylor 2013). Taylor (2013) proposed a smoothly rounded distal forewing margin as a diagnostic character of this genus. In contrast, Am. indentatum displays a characteristic indentation at the tip of the forewing, as reflected by the species name. However, the tips are not acuminate as in ‡ Am. knorrei sp. nov., similar to other species in Lithoseopsis (see Taylor 2013). Based on these observations, we propose a new taxonomic combination: Lithoseopsis indentatum (Turner, 1975) comb. nov. By excluding L. indentatum from the genus Amphientomum , this is now restricted to the Afrotropics and Palearctic (see Table 5 ). The number of described species of Lithoseopsis is hereby increased to 12 ( Johnson et al. 2023). Broadhead and Wolda (1985) mentioned the occurrence of three different species of the subgenus Amphientomum (Palaeoseopsis) in Panama. However, they remain undescribed and no details besides the collecting information are known. It is conceivable that these specimens do not belong to Amphientomum , similar to the previously stated case.

As the basal section of Rs is absent in the hindwing of ‡ Am. knorrei sp. nov. (Fig. 13A ), the species can be assigned to the subgenus Amphientomum (Palaeoseopsis) in the system of Roesler (1944). The shape of scales is arguably not a good diagnostic feature, as several types of scale shapes can occur in a single specimen. Emarginate scales are present in ‡ Am. knorrei sp. nov. (type II scales, Fig. 5H ), a diagnostic character of the subgenus Am. (Amphientomum) after Roesler (1944), but there are also scales with an evenly truncated (type I scales, Fig. 5H ) or a frayed (type III scales, Fig. 5G ) apical edge, a diagnostic criterium for Am. (Palaeoseopsis) . On the other hand, Enderlein (1911) introduced evenly truncated scales as diagnostic character for Am. (Amphientomum) , while scales with a median notch are characteristic for Am. (Palaeoseopsis) . It is likely that Roesler (1944, p. 138) was mistaken in the characterization of both subgenera. As the polarity of the presence or absence of the basal section of Rs in the hindwing is unknown, the subgenus Am. (Palaeoseopsis) is possibly not monophyletic. All species except for † Am. leptolepis and † Am. paradoxum , both described from Baltic amber, have a reduced basal section of Rs in the hindwing (Table 5 ). Several species, such as Am. loebli and Am. pauliani (Table 5 ), also have a vestigial basal section of Rs, but it is never fused with R1. Given these problematic definitions, we synonymize Palaeoseopsis under Amphientomum syn. nov. and consequently remove the subgeneric rank from Amphientomum pending future study.

Several characters of ‡ Am. knorrei sp. nov. resemble features of Am. acuminatum , like the shape of the apex of the lacinia (see Fig. 12 for comparison of all available Amphientomum species), the apical lobe of the forewing (see Figs 13 , 14 for comparison of all available Amphientomum species), as well as the claw with a single preapical tooth. Consequently, this species from Madagascar ( Smithers 1964; Badonnel 1967) might be closely related with ‡ Am. knorrei sp. nov. It differs from it by smaller size (body length = 2.1 mm, forewing length = 2.75 mm), the lower number of ctenidiobothria on the first tarsomere of the hindleg (21-22), the scale pattern on the forewings, and also the facial markings. As the origin of our piece of resin with the psocid inclusion is not fully clarified, the geographical distribution of ‡ Am. knorrei sp. nov. remains uncertain. That the specimen is enclosed in East African copal imported to Germany during colonial times is suggested by several syninclusions, for instance the Dorylus in our present collection. The countries of origin of such pieces of resin are Tanzania, Mozambique, and Madagascar ( Delclòs Martínez et al. 2020). It is therefore likely that Am. acuminatum and ‡ Am. knorrei sp. nov. have a common distribution in East Africa, while the exact distribution of both species is still unclear.

Finally, an unsolved nomenclatorial issue concerning Amphientomum ectostriolate Li, 1999 requires clarification. In the Psocodea Species File ( Johnson et al. 2023, date: 2023 August 17) the year of publication for this species is incorrectly listed as Am. ectostriolate Li, 2002 and the species Am. ectostriolatis Li, 1999 mistakenly listed as a valid taxon. We contend that the name should be Am. ectostriolate Li, 1999 based on the following reasoning: (1) The protonym, Am. ectostriolatis , was established and illustrated in the monograph on the Chinese Psocoptera (p. 199) by Li (2002); (2) the spelling was later emended by Lienhard (2003) to Am. ectostriolate Li, 1999, justifiably so by Articles 19 and 34 of the ICZN (1999), with this emendation considered to be the original spelling by section 32.2; and (3) the name Amphientomum ectostriolatum Li, 2002 should be considered an unjustified emendation by Article 33, as the author spelled the name this way in the figure legend and twice in the text, indicating an intended name change, hence this name is available but should be a junior synonym of Am. ectostriolate syn. nov.

Figures

Figure 5. A-H. Photography of ‡ Amphientomum knorrei sp. nov. preserved in piece PMJ Pa 5809. A. Habitus in dorsofrontal view; B. Habitus in ventrocaudal view; C. Right metafemur and - tibia in posterior view, rings of brown scales on metatibia; D. Distal portion of left hindleg with claw, arrow indicates preapical tooth; E. Basitarsomere of hindleg, arrows indicate ctenidiobothria; F. Right antennal flagellum, flagellomere 5, arrows indicate secondary annulation; G. Scales, arrow indicates scale type III; H. Tip of right hindwing with scales, arrows indicate scale type I and II.

Figure 6. A-C. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov. A. Habitus in frontal view; B. Habitus in dorsal view; C. Habitus in ventral view. Abbreviations: acl = anteclypeus, cs = coronal sulcus, gl = glossa, lap = labial palp, lb = labrum, mxp = maxillary palp, oc = ocellus, pcl = postclypeus, pgl = paraglossa.

Figure 7. A-C. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov. A. Habitus in left lateral view; B. Habitus in right lateral view; C. Subgenital plate in ventral view. Abbreviations: acl = anteclypeus, atp = anterior tentorial pit, dov = dorsal valve, epp = epiproct, eps = epistomal sulcus, fr = frons, ga = galea, ge = gena, gef = genal fovea, ges = genal sulcus, lap = labial palp, lb = labrum, lc = lacinia, md = mandible, occ = occiput, pap = paraproct, pcl = postclypeus, ppf = palpifer, sgp = subgenital plate, st = stipes, ve = vertex.

Figure 8. A-B. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov. A. Internal view from left side, sagittal cut; B. internal view from right side, sagittal cut. Abbreviations: car = circumantennal ridge, cor = circumocular ridge, cr = coronal ridge, epp = epiproct, epr = epistomal ridge, fl = foreleg, ger = genal ridge, hl = hindleg, lap = labial palp, lc = lacinia, ml = midleg, msf = mesofurca, msp = mesophragma, mtf = metafurca, mtp = metaphragma, pap = paraproct, parr = parapsidial ridge, prf = profurca, prn = pronotum, sgp = subgenital plate.

Figure 9. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov. Internal view of head from left side, sagittal cut. Abbreviations: acl = anteclypeus, amdad = apodeme of mandibular adductor, asas = apodeme of salivary sclerite, ata = anterior tentorial arm, car = circumantennal ridge, cor = circumocular ridge. cr = coronal ridge, ct = corpotentorium, dta = dorsal tentorial arm, epr = epistomal ridge, ga = galea, ger = genal ridge, hy = hypopharynx, lap = labial palp, lb = labrum, lc = lacinia, md = mandible, pcl = postclypeus, pom = postmentum, por = postoccipital ridge, prm = prementum, pta = posterior tentorial arm, sas = salivary sclerite, sit = sitophore.

Figure 10. A-F. Photography of ‡ Amphientomum knorrei sp. nov. A. Right maxillary palp and right portion of head in frontal view, numbers indicate maxillary palp article; B. Labrum and labial palps in dorsally inclined frontal view; C. Right foretibia in frontal view; D. Left fore- and hindwing in dorsal view, arrows indicate where the vein CuP and A 1 meet the posterior forewing margin; E. Details of paraproct and clunium from lateral view; F. Details of ovipositor from ventrolateral view. Abbreviations: clu = clunium, dov = dorsal valve, epp = epiproct,. exv = external valve, lap = labial palp, lb = labrum, md = mandible, pap = paraproct, pcl = postclypeus, vev = ventral valve.

Figure 11. A-J. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov. A. Labrum in anterior view; B. Labrum in posterior view; C. Mandibles in anterior view; D. Mandibles in posterior view; E. Maxillary palps, top left palp, bottom right palp, numbers indicate palp article; F. Laciniae in anterior view; G. Sitophore; H. Salivary sclerites in anterior (right) and posterior (left) view; I. Tentorium in dorsal view; J. Labium in anterior (left) and posterior (right) view. Abbreviations: asmd = anterior socket of mandible, asas = apodeme of salivary sclerite, ata = anterior tentorial arm, ct = corpotentorium, dta = dorsal tentorial arm, eptf = epipharyngeal transverse fold, gl = glossae, inc 1 / 2 = incisivi 1 and 2, lap 1 / 2 = labial palp article 1 and 2, lfsas = longitudinal furrow of salivary sclerite, mdce = mandibular cutting edge, mesit = median extension of sitophore, mo = mola, mor = mortar, mot = molar tooth, pcmd = posterior condyle of mandible, pgl = paraglossa, pmdt = proximal mandibular tooth, pta = posterior tentorial arm.

Figure 12. A. Photography of ‡ Amphientomum knorrei sp. nov., posterior view of hindcoxae, arrows indicate the interlocking mechanism; B. 3 D-reconstruction of ‡ Amphientomum knorrei sp. nov., posterior view of hindcoxae. Abbreviations: co = coxa, fe = femur, hce = hindcoxal emargination, hcp = hindcoxal projection, tr = trochanter.

Figure 13. A-Q. Schematized drawings of all available laciniae of Amphientomum species from the literature and of ‡ Amphientomum knorrei sp. nov. (Amphientomidae: Amphientominae) preserved in piece PMJ Pa 5809. The laciniae are not up to scale, and the orientation of the lacinia was flipped at 180 ° for C, E, H, J-L, N-P from the original drawings, only the apical portions of the laciniae are shown. A. Am. acuminatum, male; B. Am. aelleni, nymph; C. Am. annulicorne, female; D. Am. annulitibia; E. Am. dimorphum, sex not specified; F. Am. dimorphum, sex not specified; G. Am. flexuosum, female; H. Am. hieroglyphicum; I. ‡ Am. knorrei sp. nov., female, redrawn after 3 D render; J. Am. loebli, female, K. Am. mimulum, sex not specified; L. Am. montanum, female; M. Am. pauliani, male; N. Am. punctatum, male; O. Am. simile, female; P. A. simile, female; Q. Am. striaticeps, female. Figures modified from the following: A, C, E, F, H, K, L, N, O, P, Q after Badonnel (1967); D after Smithers (1999); B after Badonnel (1959); G after Badonnel (1955); J after Badonnel (1979); M after Smithers (1964).

Figure 14. A-I. Schematized drawings of all available fore- and hindwings of Amphientomum species from the literature and of ‡ Amphientomum knorrei sp. nov. (Amphientomidae: Amphientominae) preserved in piece PMJ Pa 5809. The same scale bar was used for B-I. A. ‡ Am. knorrei sp. nov., female; B. † Am. colpolepis; C. † Am. paradoxum, female; D. † Am. parisiense; E. Am. acuminatum; F. Am. annulicorne, female; G. Am. annulitibia, male; H. Am. dimorphum, female; I. Am. dimorphum, male. Figures modified from the following: B, C after Enderlein (1911); D after Nel et al. (2005); E after Smithers (1964); F, H, I after Badonnel (1967); G after Smithers (1999).

Figure A 3. Model 3 of the holotype specimen of ‡ A. knorrei Weingardt, Bock & Boudinot, sp. nov. (Amphientomidae: Amphientominae) preserved in piece PMJ Pa 5809. An interactive cybertype is available in the HTML version of this article online and on Sketchfab: URL: https: // sketchfab. com / 3 d-models / amphientomum-knorrei-a 7 e 0 f 1 c 0 c 6234093 a 384 a 51 c 2 be 48730.