Published online on Feb 28 2025
The first Canadian records of Julus scandinavius (Latzel 1884) (Diplopoda: Julidae) found in Québec and the Maritime provinces
P.-M. Brousseau (1), D.A. Hennen (2), A. Simard (3)
1. Université Concordia, 1455, Boulevard de Maisonneuve Ouest, Montréal, QC, H3G 1M8, Canada. Courriel : pierremarcbrousseau@gmail.com
2. Virginia Museum of Natural History, 21 Starling Ave, Martinsville, VA, USA, 24112. Courriel : derhennen@gmail.com
3. Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs du Québec, 880 Chemin Ste-Foy, Québec, QC, G1S 4X4, Canada. Courriel : Anouk.Simard@mffp.gouv.qc.ca
Abstract. We report the first records of the millipede Julus scandinavius in Canada. Several specimens were caught in four provinces of eastern Canada: New Brunswick, Nova Scotia, Quebec and Prince Edward Island. There are very few documented records of this European species in North America, likely due to the difficulty to distinguish it from the common species Ophyiulus pilosus. We present several morphological features that are useful for distinguishing both species.
Keywords. gonopods, introduced species, Julida, millipedes, Ophyiulus pilosus.
Résumé. Nous rapportons les premières mentions du mille-pattes Julus scandinavius sur le territoire canadien. Des spécimens ont été capturés dans quatre provinces de l'est du Canada : l'Île-du-Prince-Édouard, la Nouvelle-Écosse, le Nouveau-Brunswick et le Québec. Il existe très peu de mentions de cette espèce d'origine européenne en Amérique du Nord, probablement parce qu'elle est confondue avec Ophyiulus pilosus, une espèce commune très similaire. Nous présentons différents critères morphologiques pour distinguer les deux espèces.
Mots clés. espèce introduite, gonopodes, Julida, mille-pattes, Ophyiulus pilosus.
Introduction
As for many arthropod taxa, the endemic fauna of millipedes in eastern Canada was greatly reduced following the Wisconsin glaciation (~20,000 years ago). Although some species survived in ecological refuges at altitude, particularly in the Appalachian Mountains (Walker et al. 2009), the diversity of the endemic millipede fauna remains low (Shelley 1988). This situation was potentially favorable for the establishment of exotic species. Summarizing the current state of knowledge of the Canadian myriapod fauna, Langor et al. (2019) reported that about 32% of the described millipede species in Canada are non-native. Indeed, in the province of Quebec, nearly half of the known millipede species are of European origin, including very common ones with a wide distribution such as Ophyiulus pilosus (Newport 1842) and Cylindroiulus caeruleocinctus (Wood 1864) (Brousseau 2025).
In this paper, we report the first records of Julus scandinavius (Latzel 1884) in three Maritime provinces (New Brunswick, Nova Scotia, and Prince Edward Island) and in Quebec. These are the first Canadian records of this European species which is rarely seen in North America (Shelley 1988).
Methods
The specimens used in this paper have different origins. All specimens from the Maritime provinces were collected by hand, while the majority of those from Québec were caught with pitfall traps of the "Réseau de suivi de la biodiversité au Québec" (suivi-BQ), managed by the Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs du Québec (Simard et al. 2021). The suivi-BQ, started in 2016, and has a network of pitfall traps installed in 84 sites across the province of Quebec. These traps are active during alternating years.
Previous literature records of J. scandinavius from the northeastern United States were gathered from Jeekel (1973) and Shelley (1988). These localities were georeferenced with the program GEOLocate (Rios 2018). A distribution map of new and previous records was produced using the program SimpleMappr (Shorthouse 2010) and edited with GIMP (GIMP Development Team 2021).
Results
Specimens of J. scandinavius were found in five localities in Nova Scotia, four in Quebec, two in New Brunswick, and one on Prince Edward Island. The first specimen found in Quebec was a female, caught by hand in Neuville (46.6987° N, -71.5721° W) in the MRC of Portneuf on the shore of the Saint Lawrence River, under tidewrack on October 12th, 2021. The capture of a mature male on November 3rd 2022, in Quebec City (Cap-Rouge borough) (46.7719° N, -71.3519 W) confirms the presence of the species in the province. Furthermore, 11 specimens were found in pitfall traps from the suivi-BQ in only two sites out of the 48 where Diplopoda were caught. Eight specimens were caught at Saint-Paul (45.9494° N, -73.4380° W), in the MRC of Joliette, in summer 2018, and ten more at Saint-Henri (46.6724° N, -71.0299° W), in the MRC of Bellechasse, in summer 2021. These were identified by the first author in spring 2023.
The first specimen found in New Brunswick came from a private residence near Fredericton (exact coordinates obscured for privacy, 45.90° N, -66.58° W), where hundreds of individuals were found in the immediate area around a home. Later on, a female was found in a deciduous forest in Charlo (47.9864° N, -66.2905° W), Restigouche County, on July 7th, 2022.
All the specimens from Nova Scotia and Prince Edward Island were collected in June 2023 by the first author. Four of the five localities where J. scandinavius was found in Nova Scotia were on Cape Breton Island. The other locality was at Dayspring (44.371° N, -64.4871° W) in Lunenberg county. Only one specimen was found on Prince Edward Island in Bonshaw (46.2125° N, -63.3316° W).
Collection Data
DAH: Derek A. Hennen's private collection.
PMB: Pierre-Marc Brousseau.
Suivi-BQ: Réseau de suivi de la biodiversité au Québec, MELCCFP.
Julus scandinavius (Julidae)
CANADA: New Brunswick: Restigouche: Charlo [47.9864, -66.2905], 07.vii.2022, deciduous litter, PMB, 1♀ • Sunbury County: Fredericton [45.9, -66.58], 14.x.2019, in yard around outside of house, L. Ross, DAH, 3♂3♀ • Nova Scotia: Cape Breton County: Dalem Lake [46.2533, -60.4267], 21.vi.2023, under a log, PMB, 1♂1♀ • Groves Point [46.2305, -60.3460], 21.vi.2023, under a log in grass, PMB, 1♂ • Inverness County: Margaree Valley, Lake O'Law [46.2755, -60.9609], 21.vi.2023, wet deciduous litter by a spring, PMB, 1♀ • Port Hawkesbury [45.6275, -61.3566], 20.vi.2023, deciduous leaf litter, PMB, 1♂1♀ • Lunenburg County: Dayspring [44.3710, -64.4871], 22.vi.2023, deciduous leaf litter, PMB, 1♀ • Prince Edward Island: Queens County: Bonshaw [46.2125, -63.3316], 19.vi.2023, under a log, PMB, 1♂ • Quebec: Bellechasse: Saint-Henri [46.6724, -71.0299], 17.v–14.vii.2021, pitfall traps, suivi-BQ, 10♂♀ • Joliette: Saint-Paul [45.9494, -73.438], 17.v–06.vii.2018, pitfall traps, suivi-BQ, 1♂ • Metropolitan community of Quebec: Quebec City, Cap-Rouge borough [46.7719, -71.3519], 03.xi.2022, deciduous leaf litter, PMB, 1♂ • Portneuf: Neuville [46.6987, -71.5721], 12.x.2021, river shore, tidewrack, PMB, 1♀.
Literature records:
UNITED STATES : Maine: Hancock/Knox County, Acadia National Park [44.3507, -68.2441], R.M. Shelley (Shelley 1988) • Massachusetts: Middlesex County: Cambridge, Fresh Pond [42.3830, -71.1447], xi.1971, C. A. W. Jeekel (Jeekel 1973) • Middlesex County, Lincoln [42.4259, -71.3039] (Shelley 1988) • New York: Westchester County [41.1167, -73.8000] (Shelley 1988).
Discussion
Julus scandinavius seems well distributed on Cape Breton Island, where it was found at all sites visited except for a heath on the sea shore near Grande-Rivière. Elsewhere, the distribution seems more scattered. In mainland Nova Scotia, it was found in only one site, despite visiting several sites on the western coast (near Annapolis Royal, Middleton, Sandy Cove, and Yarmouth), in the center (near Caledonia), and along the northern coast (near Pomquet). Overall, we found specimens in a variety of habitats, including deciduous forest, grassland, urban yards, and littoral zones. In Europe, J. scandinavius seems to be more restricted by soil characteristics, with a preference for acidic, non-calcareous, and sandy soils, than by vegetation type (Kime 1995, Lee 2006).
Julus scandinavius is well distributed in Europe, from Switzerland northward (Kime 2004, Lee 2006). The first mention in North America is from Cambridge, Massachusetts, where it was found in 1971 (Jeekel 1973). Since then, it has also been collected in Maine and New York state (Shelley 1988). There are few records of this species in North America (see fig. 1), but its presence could be underestimated due to confusion with O. pilosus. Ophyiulus pilosus is far better known in North America and has a wider known distribution from Newfoundland to Ontario, and southward to Tennessee and South Carolina (Chamberlin & Hoffman 1958, Shelley 1988, DAH unpublished records). Additionally, photographic vouchers from websites such as BugGuide (Bugguide 2023) and iNaturalist (GBIF 2023) document O. pilosus on the west coast and many southern states of the United States, suggesting a larger distribution awaiting confirmation by physical vouchers. In Quebec, J. scandinavius is rare compared to O. pilosus, which is currently known from 16 localities (Brousseau 2025).
Distinguishing J. scandinavius and O. pilosus can be difficult, particularly for females and juveniles. They are best distinguished based on the male gonopods (fig. 2). In J. scandinavius, the anterior portion of the gonopods, the promere (p) and mesomere (m), differ greatly in size. The promere is elongated, somewhat cylindrical and stout, with a slight lateral swelling distally at about three-quarters of its length. The mesomere is much shorter, about half the length of the promere, and tapers to a blunt end. The posterior portion of the gonopods, the opisthomere (o), is a thumb-like process that curves slightly mesally and tapers to a blunt end. It is only slightly larger than the mesomere. The flagellum (f) is a long, sinuous structure that arises from near the base of the promere and tapers to a thin, whip-like tip slightly below the level of the promere (fig. 2b). In O. pilosus (fig. 2d), the promere and mesomere are subequal in size and tightly appressed, each with blunt tips. The opisthomere is a greatly expanded calyx-shaped structure, with a posterior leaf-like phylacum (ph) sheathing the tip of the flagellum and an anterior serrated velum (v), both of which are absent in J. scandinavius. The flagellum is a thin tapering whip-like structure that is usually concealed within the opisthomere. In addition to the male gonopods, the first leg pair differs between the species. In J. scandinavius, the first leg pair is extremely reduced and appears to be absent at first glance. In O. pilosus, the first leg pair is modified into obvious sickle-shaped structures. Furthermore, males of J. scandinavius have oblong, clavate coxal processes on their second leg pair (fig. 3), which O. pilosus males lack.
Female vulvae are less commonly used as identification criteria, but were shown to be useful to distinguish closely related Cylindroiulus species (Blower 1953). On the vulvae of J. scandinavius, the operculum is short, only slightly extending past the apex of the bursa (fig. 4a–b). Also, the distal margin of the operculum is bilobed and only slightly asymmetrical (fig. 4c). The vulvae of O. pilosus are more elongated, with the operculum clearly extending past the apex of the bursa (fig. 4d–e). The distal margin of the operculum is clearly asymmetrical, with the internal side acuminate and the external side rounded (fig. 4f).
Other criteria can be used, but these are more subjective and require a certain level of experience to be reliable. First, they slightly differ in color (fig. 5), J. scandinavius having an oily brown color, while O. pilosus tends to be darker, brown-gray to brown-black, and often the pre-anal ring is orange-red in life. However, both species tend to lose their color in alcohol, turning blueish gray. Julus scandinavius is generally stockier than O. pilosus, but there is some overlap for this criterion so that the thinner J. scandinavius are similar to the stockier O. pilosus. Blower (1985) also mentions that the setae of the metazonite (posterior section of the body ring) of O. pilosus are noticeably longer than those of J. scandinavius (fig. 5).
Finding J. scandinavius in four of the five easternmost provinces of Canada suggests a larger distribution in northeastern North America and could be expected in Ontario, New Hampshire, and Vermont. Interestingly, it is only the fourth species of millipede recorded from Prince Edward Island, which has been understudied (Shelley & Smith 2011).
Acknowledgements
" Le réseau de suivi de la biodiversité " is funded by Gouvernement du Québec through the Plan pour une Économie Verte 2030. We would like to thank Caroline Dubé for the coordination of field inventories of Suivi-BQ as well as Virginie Boivin, Martine Lavoie and Victor Renaud for their contribution in the sampling. We also thank L. Ross who collected the specimens in Fredericton, NB. Tiziano Hurni-Cranston, Pierre Paquin and Gilles Arbour revised an earlier version of the manuscript.
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