Cryphalus numidicus Eichhoff, 1878

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 numidicus Eichhoff, 1878

Cryphalus numidicus Eichhoff, 1878a: 385.

Cryphalus numidicus Eichhoff: 1878b: 487.

Type material.

According to Horn et al. (1990a), Eichhoff’s bark beetle material was transferred via C. Schaufuss and then again via H. Eggers to the Zoological Museum in Hamburg. According to Wood (1992a), the C. numidicus material in Hamburg was destroyed. Contact with the Zoological Museum in Hamburg confirmed that the material (if there) was destroyed (pers. comm. Husemann, November 2018).

Neotype designation.

We designate a neotype of Cryphalus numidicus with the express purpose of clarifying the taxonomic status. The original description was based on specimens collected in Greece ( Eichhoff 1878a). A male neotype of Cryphalus numidicus (Eichhoff, 1878) was designated (Fig. 12 ). It was collected on 31 March 2019 in Greece (37°03'21.9"N, 22°48'44.8"E) from an Abies cephalonica Loudon tree that had recently fallen. The specimen will be stored at NHMD in the entomological collections. COI sequence (Fig. 8 , NUM1 and NUM) are from specimens collected in the same branch as the neotype.

Material examined.

55 specimens from a single location in Greece (Table 1 ) were examined. Morphological measurements were done on 16 specimens from that location. The average results of the measurements are shown in Fig. 2 .

Diagnosis.

This species can be diagnosed from morphologically similar Cryphalus in Europe by the combination of circular pronotum, asperities (> 47) on pronotum in almost concentric circles, very long erect interstrial setae on the elytral declivity longer than width of second interstria. For confident identification, the male genitalia is unique. The penis body when seen from above (dorsally) is equally broad and highly asymmetric, spiralled. The entire aedeagus is ~ 0.5 mm in length (Fig. 13B-E ).

Description.

Length 1.5-1.88 mm, average size 1.68 mm. Proportions : 2.15 × as long as wide, elytra 1.30 × as long as wide, elytra 1.65 × longer than pronotum. Antennae: club with three procurved sutures marked by coarse and long setae. Funiculus with four antennomeres (with pedicel). Pronotum: dark brown to black on both slope and disc. Profile anterior to summit rounded, wider in line with summit. Apical margin with 3-7 asperities, the outer one or two pairs usually smaller, erect setae on entire lateral margins. Anterior slope with> 47 asperities, including the ones on the anterior margin. Disc between 1/4-1/5 the length of pronotum, gently sloping, weakly tuberculate surface texture with a small hair-like seta in each tubercle. 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. 13D ). Elytra: usually brown to black, if brown often darker at base, margins equally wide. Surface smooth. Striae with rows of punctures, each puncture with a short hair-like seta, punctures sometimes visible. Interstrial setae long (0.20-0.38 mm) and erect. Interstrial ground vestiture (scales) are serrated, ~ 2-3 × as long as wide and translucent brown with a weak iridescence (Fig. 13B, 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. 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. The females (1.74 mm) are on average slightly larger than males (1.66 mm). No clear difference in tubercles or carina on the frons was noticed.

Male. The aedeagus is approximately 0.6 mm and the penis body is 0.4 mm, when measured in dorsal view from the two points furthest away from each other (Fig. 5 ). The penis body when seen from above (dorsally) is highly asymmetrical, equally broad, and clearly spirally twisted. Aedeagus apodemes make up ~ 40% of the entire aedeagus length when measured from dorsal view, they are spiralled and bending downwards. The tegmen is sclerotised and completes a ring around the penis body. It is very thin and has two thin ventral apodemes, which are approximately the length of the distance between them (Figs 5 , 13C ).

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

Host plants.

In North Africa C. numidicus is known to occur on Abies pinsapo Boiss., A. numidica de Lannoy ex Carrière, Pinus halepensis Mill. and Cedrus atlantica (Endl.) Manetti ex Carrière ( Lieutier et al. 2016). In Europe it has been found in A. pinsapo , P. halepensis ( Pfeffer 1995; Lieutier et al. 2016). We collected it from A. cephalonica .

Distribution.

According to the Palearctic catalogue ( Knížek 2011), C. numidicus is found in Europe: Bulgaria, France, Greece, Italy, Spain, Switzerland; North Africa: Algeria, Egypt, Libya, Morocco, Tunisia. Asia: Turkey.

Except for Switzerland and Bulgaria, the current distribution of C. numidicus is confined to the Mediterranean region, following the distribution of the host species mentioned above. It is unclear if C. numidicus occur on Abies bornmuelleriana Mattf., Abies cilicica (Antoine & Kotschy) Carrière and A. nordmanniana in the East Mediterranean region, or if it is only C. piceae that occurs there. We collected it in Greece from A. cephalonica . See Fig. 13A for distribution map.

Bionomics.

We found adults in mating galleries near Kounoupia in Greece (37°03'21.9"N, 22°48'44.8"E) on 31st March 2019, on an A. cephalonica branch, attached to a tree that had fallen during winter, where the bark was still relatively fresh. The branches were recently infested, so activity must have started already in mid-March. This could suggest the possibility of two generations a year. A study by Beghami et al. (2020) showed that C. numidicus from Algeria was active in spring, summer, and autumn and that it could reach three generations per year, with two sister broods in early spring and summer and the second generation in mid-September to early November (under favourable weather conditions). Lieutier et al. (2016) stated "The species develops quickly and produces 1-2 generations per year depending on climatic conditions" and "the adults bore very irregular galleries (often invaded by fungi) within the phloem of thin bark on small branches of healthy trees".

Economic significance.

According to Lieutier et al. (2016), C. numidicus can cause primary damage if the population density is high and the species can be regarded as a primary and extremely dangerous pest because of its ability to infest and reproduce massively in young healthy trees. The species infests and kills apparently healthy hosts, causing the death of trees ( Lieutier et al. 2016). Following Berghami et al. (2020), C. numidicus is a “pioneer” species able to establish on relatively freshly cut material, only four months old. Cryphalus numidicus prefers the middle and top part of trees and branches of small diameter. Attacks on cedars are initiated by both C. numidicus and Phloeosinus cedri C.N.F. Brisout de Barneville, 1883; however, only the latter can attack the crown and the mid-trunk of healthy cedars. After P. cedri attacks, C. numidicus further impairs cedar defences through massive attacks ( Beghami et al. 2020).

Remarks.

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

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 8. Species tree based on COI barcodes. Support values are given as posterior probability for Bayesian analysis and ultrafast bootstrap and SH-aLRT values for maximum likelihood analysis. Nodes coloured green for PP ≥ 0.90, UFB ≥ 80 and SH-aLRT ≥ 95, yellow for either PP ≥ 0.90, UFB ≥ 80 or SH-aLRT ≥ 95, and red for PP <0.90, UFB <80 and SH-aLRT <95.

Figure 11. Sexual dimorphism of ventrite in Cryphalus spp.

Figure 12. Neotype of Cryphalus numidicus. Stored at NHMD in the entomological collections.

Figure 13. Cryphalus numidicus A distribution B lateral and dorsal view C aedeagus D SEM, specimen from Leonidio, Greece E SEM (43 x magnification), specimen from Leonidio, Greece.