Cryphalus saltuarius Weise, 1891

Justesen, Mathias Just, Hansen, Aslak Kappel, Knizek, Milos, Lindelow, Ake, Solodovnikov, Alexey & Ravn, Hans Peter, 2023, Taxonomic reappraisal of the European fauna of the bark beetle genus Cryphalus (Coleoptera, Curculionidae, Scolytinae), ZooKeys 1179, pp. 63-105 : 63

Cryphalus saltuarius Weise, 1891

Cryphalus saltuarius Weise, 1891: 336.

Bostrichus asperatus Ratzeburg, 1837: 163; suggested by Eichhoff (1878b: 137).

Cryphalus scriba de Gozis, 1886: 31; nomen oblitum ( Knížek 2017).

Type material.

Cryphalus saltuarius was first described by Gyllenhal in 1813, under the name Bostrichus asperatus . According to Horn et al. (1990a), Gyllenhal’s material was stored at the Zoological Museum in Uppsala. Wood (1967) located the type series originally used by Gyllenhal, at the Zoological Museum in Uppsala and designated a lectotype. Additionally, three paralectotypes were stored in the Germar collection at the Museum für Naturkunde in Berlin ( Wood 1972). Pictures of type material is shown in Justesen et al. (in press A).

Material examined.

98 specimens from various locations in Sweden and Norway (Table 1 ) were examined. Morphological measurements were done on 25 specimens from Norway (20) and Sweden (5). The results are shown in Fig. 2 .

Diagnosis.

This species can be distinguished from similar Cryphalus in Europe by the combination of body size usually> 1.75 mm (average 1.82 mm), randomly distributed asperities on pronotal declivity (<54), erect interstrial setae on the elytral declivity shorter than width of second interstria, setae on lateral margin of pronotum as long or only slightly shorter between apex and summit compared to setae in line with summit (character 3, Fig. 1 ), often obsolete elytral striation, elytral declivity often more or less flattened. For confident identification, the male genitalia is unique, because the penis body when seen from above (dorsally) is broadest one quarter down from the apex and then becomes increasingly narrow towards the base, it is almost bilateral in symmetry. The entire aedeagus is ~ 0.7 mm in length (Fig. 17B-E ).

Description.

Length 1.73-1.98 mm, average size 1.82 mm (lectotype 1.85 mm). Proportions : 2.28 × as long as wide, elytra 1.46 × as long as wide, elytra 1.96 × longer than pronotum. Antennae: club with three procurved sutures marked by coarse and long setae. Funiculus with four antennomeres. Pronotum: dark brown to black on both slope and disc. Profile anterior to summit almost triangular but slightly rounded, slightly wider in line with summit. Anterior margin with 2-5 asperities, the outer pair usually smaller, erect setae on entire lateral margins of pronotum. Anterior slope with <50 asperities, including the ones on the anterior margin (lectotype has 44). Disc between 1/4-1/5 the length of pronotum, gently sloped, weakly tuberculate surface texture with small hair-like setae in each tubercule. Vestiture on declivity and disc hair-like. Suture between pronotum and elytra weakly sinuate. Scutellum: small with almost no setae (Fig. 17D ). Elytra: usually dark brown or black but sometimes pale brown, margins widest 2/3 down from pronotal edge. The curvature on declivity irregularly rounded. Surface smooth. Striae usually only visible as rows of short hair-like setae. Interstrial setae short (0.05-0.08 mm) and erect. Interstrial ground vestiture is serrated, ~ 2 × as long as wide and translucent brown with a weak iridescence (Fig. 17 B, D, E ). Proventriculus: sutural teeth of irregular size, confused, in two or more longitudinal rows. Apical teeth do not extend laterally on the plate. Masticatory brush slightly <1/2 of the proventricular length (Fig. 7 ).

Sexual dimorphism. Males and females can be separated using the last ventrite (Fig. 11 ), as suggested by ( Johnson et al. 2020a). Wood (1982) also suggests that the sexes of several scolytines including Cryphalus , can be separated by males having a clearly visible 8th tergite and the females a highly reduced or absent 8th tergite. This character was not examined. Females were on average slightly larger than males, 1.79 mm and 1.84 mm, respectively. No clear difference in tubercles or carina on the frons was noticed.

Male. The aedeagus is ~ 0.7 mm long when measured vertically (i.e., from the two points furthest away from each other). The penis body when seen from above (dorsally) is almost bilaterally symmetrical and is broadest 1/4 from the apex and then becomes increasingly narrow towards the base. It is> 0.4 mm. Aedeagus apodemes makes up ~ 40% of the entire aedeagus length when measured vertically, more or less straight and bending downwards. The tegmen is sclerotised and completes a ring around the penis body. It is thin and has two ventral apodemes, which are ~ 1/2 the length of the distance between them (Figs 5 , 17C ).

Larvae. For a description of larvae see the work by Lekander (1968).

Host plants.

It is mostly mentioned from various Picea species ( Spessivtseff 1922; Wood 1992b; Pfeffer 1995; Peltonen and Heliövaara 1998; Wermelinger et al. 2002), but has also been mentioned on Abies , Pinus ( Pfeffer 1995), and Juniperus L. ( Negru 1958).

Distribution.

According to the catalogues ( Knížek 2011; Alonso-Zarazaga et al. 2023), C. saltuarius is found in Europe: Austria, Bulgaria, Belarus, Czechia, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, Liechtenstein, Montenegro, Norway, Poland, Slovakia, Sweden, Switzerland, “Caucasus”, Russia: Central European Territory, North European Territory; Asia: China: Guangxi, Sichuan, Yunnan, Russia: West and East Siberia, Far East, West Siberia.

Cryphalus saltuarius is a rather common species in the Arctic regions of Scandinavia ( Lekander et al. 1977). It is often regarded as rare in central Europe ( Negru 1958) and it was only recently discovered in France ( Noblecourt and Schott 2004). Cryphalus saltuarius has a boreo-montane distribution ( Pfeffer 1995). The species is most likely present in most mountain ranges in Europe, wherever the host species is present including, for example, countries such as Ukraine ( Nikulina et al. 2015), Romania ( Nitzu and Olenici 2009), and Slovenia ( Jurc 2003) are not mentioned in the catalogue. According to the palearctic catalogues ( Knížek 2011; Alonso-Zarazaga et al. 2023) the species is present across Russia and even in some southern provinces of China. Although Kurenzov (1941), Krivolutskaya (1996) and Yanovskij (1999) reported the species from Far East Russia, Mandelshtam (2002) did not locate any specimens to confirm these records. Like C. asperatus there is not enough information about the presence of this species in the eastern Palearctic and Caucasus. The records from the Chinese provinces are interesting if confirmed, but they may be based on misidentification of another species and need confirmation. See distribution illustrated in Fig. 17A .

Bionomics.

There are no specific studies on the life cycle of C. saltuarius . Peltonen and Heliövaara (1998) wrote that " C. saltuarius disperses during the midsummer and breeds in spruce under thin bark, e.g., in snow-broken spruce tops, branches and smaller trees". Lekander et al. (1977) found that C. saltuarius had a two-year generation cycle, with swarming in June and hibernation as larvae. These overwintering larvae complete their development in June the following year. The newly developed beetles then hibernate. Adults and larvae were observed in Østby, Norway on 22 October 2018 from a small Picea abies tree which fell in spring 2018. We hatched 72 specimens from a small branch sampled from the tree. In the Wermelinger et al. (2002) study, 62 specimens of C. saltuarius were caught by window traps. More than 90% of these specimens were caught between end of April and beginning of June, indicating a different life cycle than described above, possibly due to the different temperatures in central Europe or confusion with the very similar C. asperatus . Pfeffer (1955) mentions two generations per year, and only one generation in higher altitude sites.

Economic significance.

In Lekander et al. (1977), C. saltuarius is described as a secondary pest species, which under the right conditions can attack weakened, but still living spruce trees. Probably the harmfulness of this species is like C. piceae , in that only very weakened trees are attacked. Therefore, this species should not without question, be regarded as a pest, despite being abundant in recently dead trees.

Remarks.

For discussion on the diagnostic characters separating C. saltuarius from C. asperatus , see remarks for the latter species.

Figures

Figure 1. Morphological measurements and magnification at which they were measured.

Figure 2. The variation of measured characters in five European Cryphalus species. Pronotal lateral setae, mid (mm), refers to the length of the lateral setae on pronotum between the summit and the apex.

Figure 5. Lateral and dorsal illustration of male genitalia of five European Cryphalus species.

Figure 7. Proventricules of the five native Cryphalus species currently recognised in Europe.

Figure 11. Sexual dimorphism of ventrite in Cryphalus spp.

Figure 17. Cryphalus saltuarius A distribution B lateral and dorsal view C aedeagus D SEM, specimen from Ostby, Norway E SEM (43 x magnification), specimen from Ostby, Norway.