Argutor, Dejean, 1821

Fedorenko, D. N., 2023, New taxa of Pterostichus (Coleoptera: Carabidae) from Vietnam, Russian Entomological Journal 32 (1), pp. 16-39 : 30-34

KEY TO SUBGENERA OF THE ARGUTOR LINEAGE:

1(10) Elytra with parascutellar seta each, mostly elongated and more or less parallel-sided. Body mostly macropterous; metepisternum long, often much longer than wide. Tarsomere 5 ventrally setose to glabrous.

2(3) Prosternal process apically beaded. Tarsi without or with a median longitudinal sulcus in addition to dorsolateral sulci in ta 2 and ta 3, conspicuous anterior and more shallow posterior; ti 3 with 1–3 lateral setae. Pronotum with single, inner, basolateral sulcus on each side. Elytra with parascutellar striole missing and three (discal) setae, those d2 and d3 adjoining or proximate to stria 2. Spermatheca undifferentiated to nearly differentiated, medium-sized, annulated toward apex; bursa copulatrix medium-sized to long. — Holarctic. ....................... Argutor .

3(2) Prosternal process not apically beaded; ta 2 and ta 3 bisulcate dorsolaterally, posterior sulcus ranging from shallow to indistinct. Pronotum mostly bisulcate on each side.

4(5) Elytron with 1–3 discal setae, d2 and/or d3 adjoining stria 2; parascutellar striole long; ta 2 and ta 3 mostly with a distinct posterior dorsolateral sulcus; ti 3 asetose laterally. Female gonosubcoxite IX with 3–4 latero-apical setae. Spermatheca and bursa copulatrix medium-sized. — Holarctic. .......................................................... Phonias .

5(4) Elytron with 1–3 discal setae adjoining stria 3; parascutellar striole long to missing; ta 2 and ta 3 with posterior dorsolateral sulcus vestigial or indistinct. Female gonosubcoxite IX without latero-apical setae.

6(7) Pronotum much wider at base than at apex, PB/PA 1.4– 1.6, with lateral margin slightly explanate between fine lateral bead and a distinct sublateral line inside. Elytron with 2–3 discal setae; ti 3 with 1–3 lateral setae (occasionally absent from one side). Bursa copulatrix and, accordingly, internal sac of aedeagus increased much in length ( Fig. 100 ), spermatheca short. — Eastern Palearctic. ... .................................................................... Badistrinus .

7(6) Pronotum convex up to fine lateral bead, rounded on sides, with base less wide relative to apex, PB/PA ~1.3. Elytron with 1–2 discal setae; ti 3 without or with single lateral seta. Bursa copulatrix moderately long.

8(9) Elytron with two discal setae, d2 and d3. Body small, BL 5–5.5 mm; elytra elongated. Spermatheca short. — Eastern Palearctic. ..................................? Pledarus (part.).

9(8) Elytron with single discal seta, d3. Body larger, BL 7–9 mm; elytra shorter, sides rounded. Spermatheca long, capitate and corrugated ( Fig. 103 ). — Eastern Palearctic. ........................................................................ Pledarus .

10(1) Elytra without parascutellar seta, mostly shorter and more rounded on sides. Tarsomere 5 setose or setulose ventrally. Metepisternum shorter; ta 2 and ta 3 with posterior dorsolateral sulcus missing or imperceptible on tarsomeres 1–2 only.

11(12) Elytron with single discal seta, d3 adjoining stria 3; parascutellar striole short to missing. Pronotum with a deep fovea between inner and outer basolateral sulcus. Body apterous. .................................... Pledarus (part.).

12(11) Elytron with three discal setae, d1 adjoining stria 3, d2 and d3 adjoining stria 2; parascutellar striole long. Pronotum more or less cordate, with single, inner, basolateral sulcus on each side; basal angles slightly acute to subrectangular, not toothed. Tarsomere 5 ventrally setose. Body mostly brachypterous to apterous. — Holarctic. ........... ..................................................................... Omaseulus .

Some significant characters vary between species of this lineage considerably, as well as between individuals in some of them. These characters are as follows.

1) Lateral sulci of ti 2 and ti 3. — This sulcus is deep and well traceable in ti 2, while being more shallow in Omaseulus . Fine and deep sulcus that runs on at least apical 3/4–4/5 ti 3 is characteristic of Argutor and Phonias , but P. chameleon and P. taxonyis Csiki, 1930 have this sulcus either shallow and shorter or vague, respectively. It is traceable in apical 2/3 tibia in Badistrinus and Pledarus , while ranging from nearly entire in some specimens of P. haptoderoides to hardly traceable in apical 1/3 tibia in P. neglectus and some specimens of P. goschi . Omaseulus have the most reduced ti 3 sulcus that ranges from shallow in apical 2/3–1/2 ( P. diligens (Sturm, 1824)) through vague in apical 3/5–1/2 (the other species examined) to nearly indistinct (some specimens of many species) or missing (some specimens of P. eobius Tschitschérine, 1899 ).

These sulci are most likely to be plesiomorphic character state in Pterostichitae, which follows from the fact that pronouncedly sulcate tibiae are peculiar to higher taxa such as, e.g., Abacetina, Cratocerini, Morionini, Panagaeini, etc.

2) Protibia anterior face with a median longitudinal sulcus. — This sulcus is not characteristic of Pterostichus , but some species of the Argutor lineage have a vestigial sulcus that runs on basal 1/3–2/5 ti 1. Out of the other species examined, only P. (Falsargutor) pseudopedius Reitter, 1887 was found to have the anterior face of ti 1 with a fine yet complete sulcus, combined with another special feature, a row of a few short setae running along the inner margin below the antennal cleaner fissure. This species also has the abdominal sternite VIII and tergite VIII in female rather similar to those seen within the Argutor lineage, but spermatheca is differentiated, which is characteristic of the Pterostichus lineage D sensu Sasakawa and Kubota [2007].

3) Dorsolateral sulci in ta 2 and ta 3. — The tarsi are generally bisulcate within the lineage, the anterior (outer) sulcus being deeper than the posterior (inner) one. This difference is by comparison slight in Argutor and Phonias , which have the sulci best developed. These are wide, deep and thence conspicuous on tarsomeres 1–4 ( P. dulcis ) or slightly finer in ta 2 and still more so in ta 3 ( P. sulcitarsis , P. vernalis ), or absent from mesotarsomere 4 ( P. leonisi Apfelbeck, 1904 ; some specimens of P. vernalis ), combined with the posterior sulcus hardly traceable on mesotarsomeres 1 and 2 only ( P. chameleon ). Phonias have similar sulci except that the apical two (most species) or 2–3 ( P. stricticollis ) mesotarsomeres are not sulcate, or the mesotarsomeres 1 and 2 and the metatarsomeres 1–3 are only anteriorly sulcate ( P. taxonyis ). Badistrinus species are slightly distinctive in having basal three or four tarsomeres anteriorly sulcate, in couple with the posterior sulci being very fine and traceable on basal 2–3 mesotarsomeres and basal four ( P. haptoderoides ) or only 1–2 ( P. laticollis ) metatarsomeres.

Pledarus and Omaseulus have the most reduced dorsolateral sulci, especially the posterior ones. Mesotarsomeres 1– 2 and metatarsomeres 1–3 mostly have the anterior sulci while the posterior sulci are either missing (many Omaseulus ) or hardly traceable on basal one or two tarsomeres, mostly metatarsomeres, in Pledarus as well as in P. neglectus , P. goschi , and some Omaseulus such as P. jankowskyi ( Tschitschérine, 1897) or P. morawitzianus (Lutshnik, 1922) .

4) Ventral setae of tarsomere 5. — The tarsomere is ventrally setose in some species of Omaseulus or setulose in some others such as P. eobius or P. morawitzianus A. Morawitz, 1862 , while it varies from setose to glabrous between species of the other three subgenera. The ventral setae are reduced considerably in size yet still distinct in P. sulcitarsis , but almost imperceptible in P. kerzhneri (Lafer, 1983) , P. (Phonias) lutschniki Jedlička, 1962 and P. (Ph.) longinquus , from which it follows that the erection of Biphonias [ Jeanne, 1988] has been mere formality.

5) Pronotal basolateral sulci. — Two, well-developed, sulci on each side are certain to be plesiomorphous character state. It is observed in Badistrinus , Pledarus and many representatives of Phonias , whereas the outer, shorter, sulcus has been reduced to a punctiform vestige or totally in Argutor , Omaseulus and some species of Phonias such as P. taxonyis ; P. arrowi Jedlička, 1936 ; P. longinquus ; P. ripensis ( Motschulsky, 1866) , and P. ussuriensis , as well as in P. goschi .

6) Elytral parascutellar striole and seta. — The striole is entire or long, posteriorly adjoining stria 1 or almost so in Phonias and Omaseulus while ranging from long to missing within Badistrinus and from short to missing within Pledarus . The seta is absent from the elytra of Omaseulus and P. (Pledarus) larisae Sundukov, 2013 only.

7) Elytral discal setae. — Primary, ground plan, pattern is peculiar to Argutor , Omaseulus and some Phonias . It is defined by the seta d1 adjoining stria 1, combined with the setae d2 and d3 approximate to or adjoining stria 2. Some of these setae vary individually in number to be not seldom either doubled on or absent from one or both sides. The remainder of Phonias have only retained either the posterior two setae or but one. The setae d2 and d3 also range between stria 2 and middle of interval 3 individually, albeit occasionally, in a species, and variations of such a kind are certain to have given rise to the setation characteristic of Badistrinus first and a reduced setation of Pledarus after. The setae adjoining stria 3 are characteristic of these two subgenera, which also is true of P. perisi placed by Bousquet [1999] within Phonias .

8) Female reproductive tract.

(1) Bursa copulatrix (bc). — When folded it is obtrapezoidal, broader before than behind, with apex invaginate and slightly sclerotized, which is characteristic of not only Pterostichus but also many other carabids. This primary bursa copulatrix (bc 1) tends to be increasingly elongated in some representatives. It has become telescoped, with intercalary section (bc 2) having appeared to mediate between bc 1 and an elongated apical part ( P. vernalis ), or has evolved into a very long tube which correlates to the internal sac of aedeagus in width ( P. laticollis , P. haptoderoides ).

Basal sclerite of the seminal canal or bulbous structures as the bodies of probable sphincters at the oviduct-bursal junction have been found in no species of the lineage but P. chameleon . It has one bulb round the basal diverticulum and the other, larger, one at this junction ( Fig. 67 ). These bulbous structures are characteristic of many Pterostichus lineage D sensu Sasakawa and Kubota [2007] except Platysma Bonelli, 1810 , with its allies or derivatives such as, e.g., Adelosia Stephens, 1835 ; Plectes Fischer-Waldheim, 1822 ; Myosodus Fischer-Waldheim, 1823 ; Metallophilus Chaudoir, 1838 ; and Sinoreophilus Sciaky, 1996 .

(2) Spermatheca. — It enters bc just near oviduct-bursal junction, widely ranging between undifferentiated and nearly differentiated type as postulated by Bousquet [1999]. It is rather short annulated, more or less fusiform, and mostly has 1–2 minute diverticula toward spermatheca-bursal junction. Both number and position of these diverticula are speciesspecific characters of slight or no individual variation [Sasakawa, 2004], which point of view I incline to share. For instance, there are two diverticula on either side of the gland duct-spermathecal junction, the proximal one being closer to this junction ( P. defossus ) or adjoining bc ( Fig. 66 ). When single diverticulum is present it either adjoins bc ( P. sulcitarsis , P. chameleon ) or is situated between the gland duct-spermathecal junction and the spermatheca-bursal one ( P. lutschniki ; P. laticollis ; P. haptoderoides — Fig. 100 ), or it has given rise to the spermathecal gland duct ( P. usuriensis ). Other species examined either have no distinct deverticula ( P. vernalis , P. dulcis ) or, in contrast, have three ones. At least distal two of them are large and thence similar to underdeveloped spermathecae that begin on the gland duct-spermathecal junction ( Figs 101–102 ).

This junction also varies considerably in position from species to species. It mostly ranges within basal 1/3 spermatheca, while sometimes driving closer to its middle ( P. sulcitarsis , P. lutschniki , P. dulcis ). Variation range of the spermatheca shape and length is much wider. The spermatheca is mostly rather short, subfusiform, more or less c- or sshaped, about as long as folded bc and slightly exceeding this latter in width, broadest in about apical third, with no or not well differentiated receptacle and seminal canal. Rather slight modifications include spermathecae either clavate, more or less enlarged and broadened apicad ( Omaseulus ) or long, slender and slightly wider in apical than in basal half ( P. sulcitarsis ). Profound modification are two, spermatheca either very elongated, tubiform, somewhat corrugated, and capitate apically ( Fig. 103 ) or well-differentiated ( P. lutschniki , P. dulcis — Fig. 104 ), angled between narrow and elongated seminal canal and shortened and broadened receptacle, except only that the gland duct-spermathecal junction is proximal to (vs. just in) the angle.

It follows that the structures such as undifferentiated spermatheca, differentiated spermatheca, with well-developed receptacle and seminal canal, spermathecal diverticula and bulbous structures at the oviduct-bursal junction, occur in these or those members of the Argutor lineage, and undifferentiated spermatheca with diverticulum or diverticula dominates over the other patterns. The fact that diverticulum also occurs in Poecilus Bonelli, 1810 , as a member of the lineage sister to Pterostichus [Sasakawa, Kubota, 2007] while the most differentiated spermatheca has only been observed in P. (Argutor) dulcis may suggest that this type spermatheca has step by step evolved from undifferentiated one within the Argutor lineage.

Badistrinus is by comparison the most heterogeneous subgenus of this lineage, whereas it actually includes hardly more than four similar species ( P. laticollis , P. haptoderoides , P. modicellus , and P. kajimurai Habu et Tanaka, 1957 ). These all share many characters specified in the key below, including extremely long bursa copulatrix and internal sac of aedeagus, certainly interdependent characters. The other species listed under the subgenus [ Lorenz, 1998, 2005; Bousquet, 2003, 2017; Makarov, Sundukov, 2022] are different. Smaller sized ones, P. neglectus A. Morawitz, 1862 and P. goschi Jedlička, 1930 , are more similar to P. (Pledarus) gibbicollis with which they share the left paramere quadrate, both bursa copulatrix and endophallus shorter, and the pronotum similar in shape. However, the elytral discal setae are reduced to d 3 in Pledarus and spermatheca is unique in at least P. gibbicollis , which may suggest that a separate species group or a subgenus is required for P. neglectus with its allies.

In reassessing Pterostichus from the Russian Far East Sundukov [2013] briefly reviewed and commented on seven subgenera that shared the tr 3 with seta, cx 3 bisetose and long metepisternum, five of these subgenera belonging to the Argutor lineage. He transferred P. longinquus and allied species from Phonias to its formerly junior synonym, Biphonias , and distinguished between the two subgenera chiefly by the elytral parascutellar seta either absent or present, respectively. Yet, this resurrection proved to be invalid since the type species of Phonias had the parascutellar seta. Transfer of P. neglectus and P. goschi from Badistrinus to Biphonias was also wrong because the two species had the elytral discal setae adjoining stria 3, not stria 2 as was characteristic of Biphonias .

The elytral discal setae d2 and d3 that adjoin stria 2 argue for P. arrowi and P. arrowianus Jedlička, 1938 , to be transferred from Badistrinus to Phonias . This latter subgenus seems to be primitivemost among the others as it is largely defined by plesiomorphous characters: the body macropterous, the pronotum with both inner and outer basolateral sulcus well-developed, the tarsi distinctly bisulcate, the elytral striation and setation complete, i.e., the parascutellar striole long, combined with the parascutellar seta and three discal setae present. Furthermore, bursa copulatrix and endophallus are moderate in length and spermatheca seems to be of both shape and structure primary for the lineage as well.

Argutor is nearly the same, but for certain additional symplesiomorphies such as the apically beaded prosternal process and the laterally setose metatibia, combined with a few synapomorphies such as the dorsally trisulcate tarsi, the parascutellar striole missing (modified), and spermatheca differentiated. The remaining subgenera or groups appear to be farther advanced.

In sum, the Argutor lineage is currently recognized as a monophyletic group [Sasakawa, Kubota, 2007] well distinctive from the other Pterostichus . With this circumstance in mind, one could treat it as the separate genus Argutor while at least some subgenera it includes seem to be species groups rather than subgenera. On the other hand, some characters observed in Argutor and P. (Falsargutor) pseudopedius may argue against this point of view I am decided to share, as they link the Argutor lineage with other Pterostichus by filling some morphological gaps with themselves.

Figures

Figs 100–104. Reproductive tract in female: 100 — Pterostichus haptoderoides; 101 — P. batdaiensis sp.n.; 102 — P. stricticollis; 103 — P. gibbicollis; 104 — P. dulcis; bc — bursa copulatrix; dv — diverticulum; ov — common oviduct; rp — receptacle; sc — seminal canal; sg — spermathecal gland; 63, 65–67 — ventral aspect; 64, 68 — dorsal aspect; sgd — spermathecal gland duct; sp — spermatheca. Scale bars 1 mm. Рис. 100–104. Репродуктивный тракт самки: 100 — Pterostichus haptoderoides; 101 — P. batdaiensis sp.n.; 102 — P. stricticollis; 103 — P. gibbicollis; 104 — P. dulcis; bc — копулЯтивнаЯ сумка; dv — дивертикул; ov — непарный Яйцевод; rp — семеприемник; sc — семепровод; sg — ЖелеЗа сперматеки; sgd — проток ЖелеЗы сперматеки; sp — сперматека. Масштаб 1 мм.

Figs 63–68. Reproductive tract in female: 63 — Pterostichus austrinus sp.n.; 64–65 — P. glabellus sp.n.; 66 — P. strenuus (Panzer, 1796); 67 — P. chameleon; 68 — P. unisetosus sp.n.; 63, 65–67 — ventral aspect; 64, 68 — dorsal aspect; bc — bursa copulatrix; bs — bulbous structure; dv — diverticulum; ov — common oviduct; rp — receptacle; sc — seminal canal; sg — spermathecal gland; sgd — spermathecal gland duct; sp — spermatheca. Scale bars 1 mm. Рис. 63–68. Репродуктивный тракт самки: 63 — Pterostichus austrinus sp.n.; 64–65 — P. glabellus sp.n.; 66 — P. strenuus (Panzer, 1796); 67 — P. chameleon; 68 — P. unisetosus sp.n; 63, 65–67 — вентрально; 64, 68 — дорЗально; bc — копулЯтивнаЯ сумка; bs — бульбарное обраЗование; dv — дивертикул; ov — непарный Яйцевод; rp — семеприемник; sc — семепровод; sg — ЖелеЗа сперматеки; sgd — проток ЖелеЗы сперматеки; sp — сперматека. Масштаб 1 мм.