Phymatocera Dahlbom, 1835

Genus Phymatocera Dahlbom, 1835

Tenthredo ( Phymatocera) Dahlbom, 1835: 4 , 11. Type species: Tenthredo ( Allantus) aterrima Klug, 1816 , [= Phymatocera aterrima (Klug, 1816) ], by monotypy.

Pectinia Brullé, 1846: 664 View in CoL ; Konow 1905: 82 (as junior synonym of Phymatoceros View in CoL ). Type species: Tenthredo aterrima Klug, 1816 , [= Phymatocera aterrima (Klug, 1816) ], by monotypy.

Phymatocera : Konow 1886: 184; Enslin 1914: 267, 285; Ross 1937: 100; Ross 1951: 64; Takeuchi 1952: 43, 44; Benson 1952: 98, 100; Burks 1958: 15; Okutani 1964: 47; Muche 1969: 97, 105; Smith 1969: 41; Okutani 1972: 60; Smith 1979: 90; Goulet 1981: 801; Zombori 1982: 188; Zhelochovtsev & Zinovjev 1988: 59, 194; Abe & Smith 1991: 66; Goulet 1992: 148, 153, 156; Lacourt 1999: 198; Lee et al. 2000: 52; Lacourt 2003: 521; Pesarini 2004: 80; Wei et al. 2006: 537; Taeger et al. 2010: 344; Sundukov 2017b: 52; Lee et al. 2019: 34 View Cited Treatment ; Naito 2019: 62; Naito 2020: 361; Lacourt 2020: 302, 308.

Melanoselandria Ashmead, 1900: 606 . Not available. Nomen nudum.

Phymatoceros Konow, 1905: 77 View in CoL , 82. Name for Phymatocera Dahlbom, 1835 .

Hypargyricus MacGillivray, 1908: 290 ; Rohwer 1911: 81; MacGillivray 1916: 143, 144; Ross 1937: 100 (as junior synonym of Phymatocera ). Type species: Hypargyricus infuscatus MacGillivray, 1908 [= Phymatocera similata ( MacGillivray, 1908) ], by original designation.

Melanoselandria MacGillivray, 1909: 404 (as junior synonym of Hypargyricus ). Type species: Melanoselandria zabriskiei MacGillivray, 1909 [= Phymatocera zabriskiei ( MacGillivray, 1909) ], by monotypy.

Periclista : Malaise 1933: 59 (as senior synonym of Hypargyricus ). Not Konow, 1886.

Phymatoceropsis : Takeuchi 1952: 45 (part); Naito 2020: 362 (part). Not Rohwer, 1916.

Rhadinoceraea : Togashi 1984: 378; Naito 2019: 63; Naito 2020: 363. Not Konow, 1886.

Description. Length 4.5–11.0 mm; black, with fore leg often partly yellow or brown; wings distinctly or slightly darkened. Dorsal tentorial pit deep, open below, fused with facial furrow, with tubercle ( Figs 1A View FIGURE 1 , 5A View FIGURE 5 ). Facial furrow not shallowing near dorsal tentorial pit. Ridge around torulus not separated from torulus ( Fig. 1A View FIGURE 1 ), sometimes indistinct dorsally; its dorsomedial part distinctly protruding ( Fig. 1B View FIGURE 1 ). Antennal furrow indistinct, at most distinct beside lateral ocellus ( Fig. 1B, C View FIGURE 1 ). Inner edges of eyes converging ventrally. Clypeus widely truncate or very slightly concave on ventral edge ( Fig. 1A View FIGURE 1 ). Gena rather shiny, without genal carina ( Fig. 1D View FIGURE 1 ); minimum breadth of gena about 0.5–0.6 × basal thickness of mandible in lateral view. Antenna length more than 1.5 × head width ( Figs 13A, B View FIGURE 13 , 14A, C View FIGURE 14 , 16A, C View FIGURE 16 , 17A View FIGURE 17 , 18A, C, D View FIGURE 18 ); pedicel short, in lateral view with middle length 0.6–1.0 × breadth ( Fig. 10E–H View FIGURE 10 ); flagellum without weakly sclerotized light-colored areas; basal and middle flagellomeres scarcely or slightly bulging at apices in female ( Figs 13A View FIGURE 13 , 14A View FIGURE 14 , 16A View FIGURE 16 , 17A View FIGURE 17 , 18A, C View FIGURE 18 ), slightly or distinctly so in male ( Figs 13B View FIGURE 13 , 14C View FIGURE 14 , 16C View FIGURE 16 , 17C View FIGURE 17 , 18D View FIGURE 18 ); flagellomere 2 0.7–1.5 × flagellomere 1 in dorsal length. Labrum height 0.3–0.5 × clypeus height ( Fig. 1A View FIGURE 1 ). Apical maxillary palpomere length 1.3–1.7 × torulus height ( Fig. 6I View FIGURE 6 ). Notaulus with almost same depth and width throughout or gradually widening toward posterior end ( Figs 2A View FIGURE 2 , 6E View FIGURE 6 ). Meso- and metascutella smooth, without distinct punctures or wholly or mostly covered with indistinct minute punctures of uniform size ( Figs 2A View FIGURE 2 , 6A View FIGURE 6 ). Mesoscutellar appendage shiny, smooth and glabrous. Cenchrus with width (major axis) 1.8–3.1 × length (minor axis) ( Figs 17E View FIGURE 17 , 18G View FIGURE 18 ); distance between cenchri 0.4–0.7 × cenchrus width. Mesepisternum without distinct punctures or widely covered with indistinct minute punctures of uniform size ( Figs 2B View FIGURE 2 , 4G View FIGURE 4 ); epicnemium present, separated from mesepisternum by wide furrow ( Figs 2B, D View FIGURE 2 , 4G View FIGURE 4 , 10C, D View FIGURE 10 ); anterior marginal ridge present ( Fig. 2B View FIGURE 2 ) (absent in P. sp.-1, Fig. 2D View FIGURE 2 ), and connecting seamlessly with epicnemium (very rarely distinguishable from epicnemium by wrinkle). Anepimeron without membranous part (with wide membranous part in P. sp.-1). Mesosternum normal, i.e. deeply sunken between hind coxae. Metapleuron ( Fig. 2C View FIGURE 2 ) with metepimeron mostly glabrous and metepisternum mostly covered with setae; metepimeron with furrow curved and posteriorly fused with short furrow of metepisternum; metepimero-episternal suture distinct only above anterior depressed part of metepisternum; anterior depressed part of metepisternum well developed, not linear; metepisternum with short furrow along posterior edge. Anterior spur of fore tibia with dorsal plate apically protruding angularly ( Fig. 2E View FIGURE 2 ). Tarsomeres 1–4 of all tarsi each with plantar lobe ( Fig. 2F View FIGURE 2 ). Tarsal claws without basal lobe, with inner tooth ( Figs 13D View FIGURE 13 , 14D View FIGURE 14 , 16D View FIGURE 16 , 17F, G View FIGURE 17 , 18E, F View FIGURE 18 ). In fore wing, base of vein Rs+M located at or near junction of veins R and M ( Fig. 2G View FIGURE 2 ); vein Rs+M straight or slightly curved; cell 1M with lateral angle almost right or acute and posterolateral angle almost right or obtuse ( Figs 2G View FIGURE 2 , 11A View FIGURE 11 ); proximal part of vein 2A+3A bifurcate ( Fig. 2H View FIGURE 2 ), divided into straight main part and small piece ( Fig. 2G View FIGURE 2 ), or rarely simple and straight ( Fig. 2I View FIGURE 2 ); cell 1A open ( Fig. 2G, I View FIGURE 2 ), very rarely closed ( Fig. 2H View FIGURE 2 ); if cell 1A closed, its length about half length of cell 2A. Hind wing with cell R1 closed ( Fig. 2J View FIGURE 2 ); crossvein m-cu present; male hind wing identical to female hind wing, without marginal vein. Ovipositor sheath 0.40–0.54 × as long as abdomen ( Fig. 2K View FIGURE 2 ). Lancet almost straight or sinuate ( Figs 13F View FIGURE 13 , 18I View FIGURE 18 ), with ctenidial teeth being simple setae ( Figs 2L View FIGURE 2 , 18J View FIGURE 18 ). In male genitalia, digitus of volsella with medial edge slightly sinuate or mostly straight ( Figs 2M View FIGURE 2 , 13J View FIGURE 13 ); anterior end of harpe far apart from base of basiparamere in ventral view ( Fig. 2N View FIGURE 2 ); penis valve without spine or lobe protruding laterally ( Fig. 2M View FIGURE 2 ) (in P. satoi sp. nov., penis valve with dorsolateral lobe at apex, Fig. 11E View FIGURE 11 ).

Larva. Trunk covered with conical tubercles ( Fig. 15A, B View FIGURE 15 ); abdominal terga 1–8 each with six annulets ( Lorenz & Kraus 1957, Okutani 1959, Smith 1969).

Host plants. Asparagales : Polygonatum , Smilacina ( Okutani 1967, Smith 1969, Lacourt 2020). Liliaceae : Streptopus ( Lacourt 2020) .

Species groups. Smith (1969) divided Phymatocera into three species groups: The group 1, for two Palearctic species, P. aterrima and P. nipponica , with a deep genal-orbital groove ending in a pit, the tarsal claws each with a long outer tooth sharply bent over at its apex and with an inner tooth subequal in length to the outer tooth, and the male antenna with long erect setae; the group 2, for some Nearctic species, without a genal-orbital groove and pit, and with the tarsal claws as those in the group 1 and the male antenna without conspicuous erect setae; and the group 3, for some Nearctic species, similar to the group 2, but with the tarsal claws each with the outer tooth short, not sharply bent over, and with the inner tooth small. The groups 2 and 3 differ only in the shape of their tarsal claws, but P. racemosae Smith, 1969 shows great variation in this shape, obscuring the distinction between the two groups (see Smith 1969, Goulet 1981). Therefore, it is better to consider the groups 2 and 3 together as one group. We refer to Smith’s group 1 as the group of P. aterrima (Klug, 1816) , and the group consisting of Smith’s groups 2 and 3 as the group of P. fumipennis (Norton, 1861) .

Remarks. Phymatocera is distinguished from the other Japanese genera of the Blennocampinae , as stated in the key below. Incidentally, “ Cladardis hartigi ” (auct. non Liston, 1995; e.g. Naito 2019, 2020), Paracharactus leucopodus Rohwer, 1910 and Rhadinoceraea fuscata Togashi, 1984 , the only Japanese species in their respective genera, have been placed in the wrong genera. The generic positions of the former two species will be discussed in separate papers. Rhadinoceraea fuscata Togashi, 1984 is moved to Phymatocera in this paper.

Phymatocera is very similar to Paracharactus , Phymatoceriola , Rhadinoceraea and Veratra . Of the latter four, Paracharactus , Rhadinoceraea and Veratra are not found in Japan and are not included in the key below.

According to Smith (1969), Paracharactus is often difficult to distinguish Phymatocera because of the considerable variation, but the males of Phymatocera and Paracharactus are distinguished by their genitalia: Phymatocera has the harpe not projecting anteriorly and its anterior end far apart from the basiparamere base ( Figs 2N View FIGURE 2 , 11C–E View FIGURE 11 ; figs 198, 200 in Smith 1969), whereas Paracharactus has the harpe extremely projecting anteriorly and its anterior end close to the basiparamere base (figs 202, 204 in Smith 1969); the valviceps of a penis valve is various but never rectangular in Phymatocera ( Figs 13L View FIGURE 13 , 14M View FIGURE 14 , 16K View FIGURE 16 , 18O View FIGURE 18 ; figs 199, 201 in Smith 1969; fig. 97- 9 in Lacourt 2020), but it is rectangular in Paracharactus (figs 203, 205 in Smith 1969). In females, there is no difference between these genera. However, the Phymatocera aterrima group has a genal-orbital pit, but Paracharactus does not. The Phymatocera fumipennis group is distinguished from Paracharactus by the characters stated by Goulet (1992). In this group, the dorsal membranous area of the abdominal segment 1 is large and bell-shaped or triangular ( Figs 17E View FIGURE 17 , 18G View FIGURE 18 ; fig. 273 in Goulet 1992) and the length of the plantar lobe of the female hind tarsomere 1 is about 1/3 the distance between the plantar lobes of the hind tarsomeres 1 and 2, but in Paracharactus , this membranous area is small and inverted funnel-shaped (fig. 274 in Goulet 1992) and the length of the plantar lobe of the female hind tarsomere 1 is about 2/3 the distance between the plantar lobes of the hind tarsomeres 1 and 2. Goulet (1992) also distinguished Nearctic Phymatocera and Paracharactus by the clarity of the division of a katepimeron. However, in our material, it is often difficult to determine whether the division of a katepimeron is clear or unclear, and many species show considerable variability in the clarity of the division.

Phymatocera is distinguished from Phymatoceriola by the characters in the key below and the lancet. The lancet is straight or sinuate, with simple ctenidial setae in the former ( Figs 2L View FIGURE 2 , 13G, I View FIGURE 13 , 14F, H View FIGURE 14 , 16F, H View FIGURE 16 , 18I, J View FIGURE 18 ), but it is gently curved, with basally-thickened ctenidial setae in the latter ( Hara et al. 2024, figs 4H–J, 5J–L, 6L–N).

The only distinguishing character of Phymatocera from Rhadinoceraea and Veratra is the presence of an epicnemium. In Phymatocera , the anterodorsal part of the mesopleuron is raised, separated from the mesepisternum by a groove, and differentiates into an epicnemium ( Figs 2B, D View FIGURE 2 , 4G View FIGURE 4 ), but in Rhadinoceraea and Veratra , the anterodorsal part of the mesopleuron is not raised at all and lacks a groove anterodorsally, similar to Fig. 4H View FIGURE 4 . However, the distinctness of an epicnemium is variable within Phymatocera . Phymatocera fuscata has the epicnemium slightly raised and separated by an indistinct epicnemial groove ( Fig. 10C View FIGURE 10 ). The indistinctness of the epicnemium is probably one of the reasons why Togashi (1984) placed P. fuscata in Rhadinoceraea . The P. aterrima group is distinguished from Rhadinoceraea by the long flagellar setae in the male and from Veratra by the presence of a genal-orbital pit. The P. fumipennis group is distinguished from Rhadinoceraea by the lack of a genal-orbital pit and from Veratra by the tarsal claws with an inner tooth. We transfer two Chinese species, Phymatocera foveata Wei, 1998 and Phymatocera sinica Wei, 2002 , to Rhadinoceraea , because they do not have an epicnemium and their male flagellar setae are short. For more details, see the section for these two species below.

Phymatocera is morphologically quite diverse, and no characters suggesting its monophyly have been found. On the other hand, the P. aterrima group is more similar to Phymatoceriola and Rhadinoceraea than to the P. fumipennis group in having a genal-orbital pit. The generic classification of Phymatocera and similar genera appears to require reconsideration.