Cryphalus intermedius Ferrari, 1867

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 intermedius Ferrari, 1867

Cryphalus intermedius Ferrari, 1867: 79.

Type material.

According to Horn et al. (1990a), the type material was stored at the Natural History Museum in Vienna. However, no type material was located in that museum (pers. comm. Schillhammer 2018).

Material examined.

18 specimens from a single location in Germany (Table 1 ). Morphological measurements were done on specimens from Germany (7). The average results are shown in Fig. 2 .

Diagnosis.

This species can be diagnosed from morphologically similar Cryphalus in Europe by the combination of size (usually> 1.93 mm), the broadness (elytral width is 0.9-1 mm), interstrial setae on the elytral declivity short (<0.05 mm), the penis body ~ 0.55 mm in length (Fig. 14B-E ).

Description.

Length 1.83-2.10 mm, average size 1.98 mm. Proportions : 2.10 × as long as wide, elytra 1.29 × as long as wide, elytra 1.70 × longer than pronotum. Antennae: club with three procurved sutures marked by coarse and long setae. Funiculus with four antennomeres (including pedicel). Pronotum: dark brown to black on both slope and disc. Profile anterior to summit rounded, wider in line with elytral margin. Anterior margin with 2-6 asperities, the outer ones usually smaller, anterior marginal asperities small, erect setae on entire lateral margins. Anterior slope with <54 asperities, including the ones on the anterior margin. Disc ~1/4 the length of pronotum, gently sloped, weakly tuberculate surface texture with small hair-like setae. Vestiture on declivity and disc hair-like. Suture between pronotum and elytra weakly sinuate. Scutellum: with few trifurcate setae on the margin towards elytra (Fig. 14D ). Elytra: usually brown to black, elytral margins equally wide. Surface smooth. Striae with rows of punctures, each puncture with a short hair-like seta, punctures visible and continues on declivity. Interstrial setae short (0.03-0.05 mm) and erect. Interstrial ground vestiture (scales) are serrated, ~ 2-3 × as long as wide and translucent brown with a weak iridescence (Fig. 14B, D, E ). Proventriculus: sutural teeth of irregular size, confused, in two or more longitudinal rows. Apical teeth extend laterally over the entire segment. Masticatory brush slightly <1/2 of the proventricular length (Fig. 7 ).

Sexual dimorphism. Not enough specimens were available to evaluate difference between males and females, but probably the last ventrite can be used to separate males and females externally, 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.

Male. The aedeagus is probably the biggest among the European species, but due to destroyed apodemes, it was not possible to evaluate the entire length of the aedeagus. The penis body is ~ 0.55 mm, when measured in a dorsal view from the two points furthest away from each other. The penis body when seen from above (dorsally) is almost symmetrical, it is narrowest at the tip and broadens until ~ 1/4 from the base, where it slightly narrows again. Aedeagus apodemes were destroyed during extraction of the aedeagus. The tegmen is sclerotised and completes a ring around the penis body. It is well developed and has two long ventral apodemes, that are ~ 2 × the length of the distance between them (Figs 5 , 14C ).

Larvae. Nothing is known about the characteristics of the larvae of this species.

Host plants.

It is known from Larix decidua Mill. ( Escherich 1923; Grüne 1979; Pfeffer 1995) and Pinus ( Ferrari 1867; Grüne 1979).

Distribution.

According to the Palearctic catalogue ( Knížek 2011; Alonso-Zarazaga et al. 2023), C. intermedius is found in Europe: Austria, Czechia, France, Germany, Hungary, Italy, Liechtenstein, Poland, Romania, Slovakia, Slovenia, Switzerland, Ukraine.

The current distribution of C. intermedius is correlated with the natural range of Larix decidua . However, considering that most surrounding countries outside the natural range of L. decidua , have commercial L. decidua plantations, it is likely that C. intermedius will expand to these plantations in the future. For instance, C. intermedius is mentioned from northern Germany in the second supplement to the checklist of German beetles ( Köhler 2011). It has also been collected from pine (Ferrari, 1867; Grüne 1979). Grüne (1979) mentions that it occurs in the Alps. See Fig. 14A for distribution map.

Bionomics.

The life cycle of the species has not been described in detail. We collected pupae and newly developed adults on 8th of July 2018 from a fallen, but still fresh Larix decidua branch near Dresden, Germany (51°04'26.4"N, 14°28'57.3"E). The number of generations has not been studied in detail, but Trédl (1908) observed newly infested larch branches in July/August and found well developed adults in the same branches in October. Similar to our observations, Trédl (1908) also found well developed adults in July. Wermelinger et al. (2002) collected 18 adult specimens in traps between mid-May and late June. The flight activity in mid-May, the newly developed adults collected in July, and Trédl’s observation of well-developed beetles in October ( Trédl 1908) indicate that C. intermedius may have two generations per year, as mentioned by Pfeffer (1955).

Economic significance.

As far as we know, there has been no reports of this species causing harm to living trees.

Remarks.

Several authors found that the elytra of C. intermedius is 1.33-1.36 × as long as wide and that the body size is ~ 2 mm ( Ferrari 1867; Grüne 1979; Pfeffer 1995; Noblecourt and Schott 2004). The seven specimens measured in this study were on average 1.98 mm in body size (1.83-2.10 mm) and elytral proportions were on average 1.32 (1.26-1.38) as long as wide.

Pfeffer′s key (1995) also mentions impressed striae posteriorly on the elytra. This character was not measured but we found it a good diagnostic character.

Figures

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 14. Cryphalus intermedius A distribution B lateral and dorsal view C aedeagus D SEM, specimen from Dresden, Germany E SEM (43 x magnification), specimen from Dresden, Germany.