Lotharingibelus, Weis & Mariotti & Pignatti & Delsate, 2025

Weis, Robert, Mariotti, Nino, Pignatti, Johannes & Delsate, Dominique, 2025, Lotharingibelus n. gen., a new belemnite genus from the upper Toarcian Minette ironstones of the NE Paris Basin, Geodiversitas 47 (23), pp. 767-781 : 771-778

Genus Lotharingibelus n. gen.

urn:lsid:zoobank.org:act:

TYPE SPECIES. — Belemnites meta Blainville, 1827 (synonym of Belemnites brevis var. C Blainville, 1827).

ETYMOLOGY. — Named after Lotharingia, a medieval kingdom comprising present-day Lorraine ( France), Luxembourg, Saarland ( Germany), Netherlands, most of Belgium, and Germany west of the Rhine, and corresponding roughly to the main geographic distribution of the taxa herein included.

INCLUDED SPECIES. — Belemnites meta Blainville, 1827 ; Belemnites subgiganteus Branco, 1879 .

OCCURRENCE. — Late Toarcian (Dispansum to Aalensis zones) of NE France ( Lorraine), Luxembourg,SE Belgium (Gaume),Northern Germany.

DIAGNOSIS. — Megateuthidid possessing a conical to cylindroconical orthorostrum with a short and obtuse apical part, and a small cavity on the tip of the apex. Apical grooves absent; a shallow dorsolateral depression on each flank. Alveolus deeply penetrating and eccentric. Alveolar angle 28-32°. Epirostrum rudimentary or well-developed. REMARKS

The taxa included herein in Lotharingibelus n. gen. have been attributed in the past to the genera Dactyloteuthis Bayle, 1878 , Arcobelus Sachs in Sachs & Nalnjaeva, 1967, Brevibelus Doyle, 1991 (synonym of Brachybelus Naef, 1922 ), Homaloteuthis Stolley, 1919 , Megateuthis Lissajous, 1915 , and Mesoteuthis Lissajous, 1915 . Lotharingibelus n. gen. is distinguished from the similarly shaped Dactyloteuthis by its more conical profile, the deeper penetrating alveolus and the absence of apical grooves on the orthorostrum. It is distinguished from the Boreal-Arctic genus Arcobelus by the presence of epirostral development and a lower alveolar angle. The genus Megateuthis (synonym of Mesoteuthis ) differs from Lotharingibelus n. gen. by the presence of two dorsolateral apical grooves and a shallower alveolus. The coeval genus Brevibelus is distinguished from Lotharingibelus n. gen. by the shorter and more slender, cylindrical rostrum, a typically mucronate apex and the absence of an epirostral development.

Lotharingibelus meta ( Blainville, 1827) n. comb. ( Figs 3 A-E; 4A-D)

Belemnites meta [also cited as Belemnites brevis var. C] Blainville, 1827: 87, pl. 3, fig. 3. — Deshayes 1830: 131. — d’Orbigny 1846a: pl. 77, figs 8, 9; 1846b: pl. 37, figs 8, 9; 1846c: 566, pl. 77, figs 8, 9; 1855: 357, pl. 77, figs 8, 9. — Giebel 1852: 114. — Hébert 1865: 203. — Benecke 1898: 36, pl. 2, figs 5, 8, 9; 1905: 299. — Schwegler 1938: 473; 1969: 191, fig. 76a, b. Belemnites meta var. compressa – Benecke 1898: 39, pl. 2, figs 6, 6a, 7, 7a (correct identification: Arcobelus lucilinburhucensis Weis, 1999 ).

non Belemnites meta – Janensch 1902: 111, pl. 12, figs 4, 4a. — Werner 1912: 138, pl. 12, figs 5-7 (correct identification: Dactyloteuthis levidensis ( Simpson, 1855) , fide Schlegelmilch [1998]).

non Belemnites cf. meta – Janensch 1902: 112, pl. 12, figs 3, 3a (correct identification: Dactyloteuthis levidensis ( Simpson, 1855) , fide Schlegelmilch [1998]).

Homaloteuthis meta – Bülow-Trummer 1920: 123.

Brachybelus meta – Naef 1922: 241.

Belemnites (? Homaloteuthis ) meta – Ernst 1924: 81; pl. 6, figs 6a, 6b.

Dactyloteuthis meta – Lissajous 1925: 27, 109. — Sturz 1958: 54, pl. 6, fig. 4; pl. 7, fig. 1. — Schirardin 1961: 114.

Dactyloteuthis cf. meta – Kolb 1942: 155, pl. 7, figs 8a, 8b.

non Dactyloteuthis aff. meta – Nutsubidze 1966: 156, pl. 37, figs 5, 6 (correct identification: Acrocoelites conoideus (Oppel, 1856) fide Dzyuba et al. [2015]).

non Acrocoelites ( Toarcibelus) meta – Riegraf et al. 1984: 154, fig. 48g (correct identification: Acrocoelites levidensis ( Simpson, 1855)) .

Brevibelus cf. gingensis – Doyle 1992: 63, pl. 24, fig. 6.

Catateuthis meta – Riegraf 1995: 32.

Arcobelus meta – Schlegelmilch 1998: 68, pl. 11, fig. 5. — Riegraf et al. 1998: 66, 211. — Weis 1999: 220, fig. 36. — Neige et al. 2021: appendix S3 (taxonomical dataset).

Arcobelus lucilinburhucensis Weis, 1999: 221 , fig. 35 (compressed variety).

TYPE MATERIAL AND LOCUS TYPICUM. — Lectotype. France • Paris Basin , surroundings of Nancy, designated by Hébert (1865) as ‘type’ of the species; UCBL-EM 75009 ( Deshayes coll.) ( Fig. 3A).

ADDITIONAL MATERIAL. — France • 1 specimen ; Paris Basin, Meurthe-et-Moselle, Lay-Saint-Christophe near Nancy ; “Aalénien” (nowadays upper Toarcian ) ; MAN 2023.0.168 ( Fig. 3B) • 1 specimen ; Paris Basin, Meurthe-et-Moselle, Moulins , Bouxières-aux-Chênes ; “Aalénien (zone du minerai)” (= upper Toarcian ) ; MAN 2023.0.165 ( Fig. 4B). Belgium • 125 specimens ; Paris Basin, Halanzy and Musson, Mont-Saint-Martin Formation, old mining heaps; upper Toarcian ; Dominique Delsate leg.; MNHNL DOU989 a-h ( Figs 3D, E; 4 C-E). Luxembourg • 1 specimen ; Paris Basin, Esch-sur-Alzette ; ironstones; upper Toarcian ; MNHNL DOU882 ( Fig. 3C) • 1 specimen, Paris Basin , Differdange ; Mactra subzone, Aalensis Zone ; MNHNL DOT500 ( Fig. 4A) .

OCCURRENCE. — Upper Toarcian. Dispansum Zone (common): Luxembourg; Gaume, Belgium; Lorraine, France. — Dispansum Zone (very rare): Dehmen, Northern Germany; Blea Wyke Point, North Yorkshire, United Kingdom;?Mistelgau, Franconia, Southern Germany ( Kolb 1942). — Pseudoradiosa and Aalensis (Mactra subzone) zones (occasionally present): Luxembourg; Gaume, Belgium; Lorraine, France.

DESCRIPTION

Medium-sized, stout, conical rostrum (elongation index between 0.7 and 1; Table 2). The profile is ventrally asymmetrical, conical. The outline is symmetrical and cylindriconical. Orthorostrum without grooves. Cross section elliptical, strongly compressed (compression index between 1.12 and 1.26; Table 2). Apical region smooth, sometimes with shallow dorsolateral depressions that extend laterally towards the rostrum cavum. The tip of the apical region shows often a looser calcification resulting in a navel-shaped cavity, which is indicative of a very short epirostral stage. The flanks are more or less flattened. The alveolus occupies approximately two third of the rostrum and is ventrally displaced. The apical line is weakly goniolineate. Alveolar angle 29-32°.

REMARKS

Lotharingibelus meta n. comb. is distinguished from the taxa assigned to Dactyloteuthis by its more conical profile, the deeply penetrating alveolus and the absence of a ventral apical groove. ‘ Dactyloteuthis ’ crossotela (Blake in Tate & Blake, 1876) from the United Kingdom is a slightly younger species, that bears some resemblance with L. meta n. comb. (see also Doyle 1992); it is however distinguished from the latter by its more cylindrical profile and the presence of an epirostrum. Further investigation of the type material of D. crossotela is needed to investigate the question whether D. crossotela could represent an early taxon of Lotharingibelus n. gen. rather than Dactyloteuthis . Lotharingibelus meta n. comb. is chiefly distinguished from L. subgigantea by the presence of a well-developed epirostrum and a more conical orthorostrum in the latter.

TAXONOMIC HISTORY

In his monograph on the belemnites, Blainville (1827) established Belemnites brevis and distinguished three varieties, A, B, and C; for the latter, he proposed conditionally the name Belemnites meta . According to Article 15.1 of the ICZN (1999), “A new name or nomenclatural act proposed conditionally and published before 1961 may be available”. Thus, the valid name for variety C of Belemnites brevis is Belemnites meta . This nominal species-group taxon was based on syntypes: a single specimen of the Deshayes collection from the “Oolithe ferrugineuse” (Minette ironstones) from the surroundings of Nancy (Meurthe-et-Moselle; Fig. 1), and an unspecified number of specimens from the d’Orbigny collection from the vicinity of L’Aiguillon-la-Presqu’île, Vendée department, in the Pays de la Loire region in Western France. Deshayes (1830) considered that “pour éviter toute méprise, nous conservons le nom de Belemnites brevis à la variété C”. He thus designated as (lecto)type for Belemnites brevis the specimen of var. C figured in Blainville (1827: pl. 3, figs 3, 3a) and thus B. brevis and B. meta would have the same type and would become synonyms. However, this nomenclatural act is to be considered invalid, because Blainville (1827) introducing the name B. meta for var. C, restricted the syntypes of B. brevis to the specimens included in his varieties A and B. The nomenclatural act by Deshayes (1830) of chosing as lectotype for B. brevis a specimen attributed by Blainville (1827) to another species-group taxon ( B. meta ), corresponds to the proviso of Art. 74.2 of the ICZN (1999): “ Lectotype found not to have been a syntype. If it is demonstrated that a specimen designated as a lectotype was not a syntype, it loses its status of lectotype ”. This issue was solved by Hébert (1865), who recognized the three varieties ofBlainville (1827) as distinct species and indicated as (lecto)type for B. meta the specimen of var. C figured in Blainville (1827).

The generic attribution of Belemnites meta has varied. Earlier authors ( Bülow-Trummer 1920; Naef 1922) attributed it to Homaloteuthis , or to Brachybelus (synonym of Brevibelus ). Lissajous (1925) was the first to attribute it to the genus Dactyloteuthis due to its stout rostrum and blunt apex. This attribution was followed by Kolb (1942) and Sturz (1958). Schlegelmilch (1998) instead attributed it to the genus Arcobelus sensu Doyle, 1994 , previously known only from northern Siberia and the Russian Far East ( Sachs & Nalnjaeva 1970). The latter attribution was maintained by Weis (1999) and Neige et al. (2021).

Lotharingibelus subgiganteus ( Branco, 1879) n. comb. ( Figs 5 A-C; 6A-E)

Belemnites subgiganteus Branco, 1879: 101 , pl. 6, figs 2, 2a-e. — de Roebe 1881: 549. — Benecke 1905: 292, pl. 27, figs 1-4. — Hof 1994: pl. 2, fig. 3 (specimen to the right).

Belemnites sp. – Benecke 1898: 48-49, pl. 4, figs 10-13 (orthorostra).

Mesoteuthis subgiganteus – Schirardin 1961: 115.

Megateuthis subgigantea – Riegraf 1995: 54. — Weis 1999: 232, figs 11, 39-40. — Neige et al. 2021: Appendix S3 (taxonomical dataset).

Dactyloteuthis crossotela (Blake) – Weis 1999: 219, figs 33-34 (orthorostra).

TYPE MATERIAL. — Neotype. Luxembourg • Paris Basin , Differdange , Oberkorn , Kiemerchen; 49°30’16”N, 5°53’07”E; “couche grise” (Pseudoradiosa Zone); upper Toarcian; MNHNL TO265 ( Fig. 5A).

ADDITIONAL MATERIAL. — France • 3 specimens ; Paris Basin, Meurthe-et-Moselle, Thil ; upper Toarcian ; MNHNL DOT505 a, DOT505b, DOT505c ( Fig. 5C) • 1 specimen (with epirostrum) ; Paris Basin, Meurthe-et-Moselle, south of Nancy , Ludres ; upper Toarcian ; MAN 2023.0.166 ( Fig. 6A) • 1 specimen (orthorostrum) ; Paris Basin, Meurthe-et-Moselle, Maxéville near Nancy ; upper Toarcian ; MAN 2023.0.163 ( Fig. 6C).

Luxembourg • 2 specimens ; Paris Basin, Differdange, Oberkorn, Kiemerchen; “couche grise”; Pseudoradiosa Zone, upper Toarcian ; MNHNL DOT511 a, DOT511b ( Figs 5B; 6E) • 1 specimen (orthorostrum) ; Paris Basin, Niederkorn; upper Toarcian ; MNHNL DOU997 • 1 specimen (orthorostrum) ; Paris Basin, Rumelange; “couche grise”; upper Toarcian ; MNHNL LG101 ( Fig. 6B) • 4 specimens (with epirostrum) ; Paris Basin, Esch-sur-Alzette; “couche noire”; upper Toarcian ; MNHNL DOU514 , DOU559 a-c • 1 specimen (orthorostrum) ; Paris Basin, Differdange; upper Toarcian ; MNHNL DOT470 ( Fig. 6D) • 1 specimen (with incomplete epirostrum) ; Paris Basin, Differdange; “base du calcaire supérieur” (Mactra subzone); upper Toarcian ; MNHNL DOT499 .

TYPE HORIZON. — “Couche grise de Differdange”, Minette ironstone formation (Pseudoradiosa Zone) ( Maubeuge 1947; Di Cencio & Weis 2020).

TYPE LOCALITY. — Luxembourg, Paris Basin, Differdange, Oberkorn, Kiemerchen, a former mining site, nowadays a protected area ( Weis 2022).

OCCURRENCE. — Paris Basin ( France, Luxembourg, and Belgium), upperToarcian (Dispansum Zone to Mactra subzone, Aalensis Zone ).

DESCRIPTION

Large to very large sized, elongate-conical rostrum with epirostral development. The profile and the outline of the orthorostrum are symmetrical and conical. The profile of the epirostrum is slightly asymmetrical, conical to cylindriconical, its outline is symmetrical and cylindriconical. The apex of the orthorostrum is striated but bears no grooves. The epirostrum bears two long and incised dorsolateral grooves and several, irregular dorsal and ventral striae. The cross section is elliptical, compressed (compression index between 1.16 and 1.24; Table 2). The alveolus occupies one third to one fifth of the total rostrum length and one half of the sole orthostrum length. The alveolus is slightly displaced towards the venter. The apical line is goniolineate. Alveolar angle 28-30°.

REMARKS

Branco (1879) reported the species from his “Oberregion der Schichten mit Trigonia navis”, currently uppermost Toarcian, Pseudoradiosa Zone ( Maubeuge 1947; Di Cencio & Weis 2020) from three localities: Ars, St.-Quentin near Metz, and Villerupt. The type material ( syntypes) described by Branco (1879), originally housed in the collections of the Geologische Landessammlung von Elsass-Lothringen in Strasbourg, was destroyed in a fire in 1967 (Jean-Claude Gall, pers. comm. 1998) and has to be considered as definitely lost (Kévin Janneau, pers. comm. 2022). We herein select as the neotype specimen MNHNL TO265 from the “Couche grise de Differdange” of the Minette ironstone formation in the Kiemerchen section (southwest of Oberkorn, Luxembourg) ( Fig. 5A). This locality, a former mining site, nowadays a protected area ( Weis 2022), is situated 4 km away from the town of Villerupt and is located in the same geological sub-basin of Differdange- Longwy ( Fig. 1); the neotype is from the same geological horizon and formation of the syntypes. The designation of a neotype is considered necessary in order to clarify the taxonomic status of Belemnites subgiganteus and in particular its differential characters in respect to Belemnites meta .

L. subgiganteus n. comb. bears some resemblance with the epirostrum-bearing specimens of Dactyloteuthis crossotela . However, the orthorostrum of L. subgiganteus n. comb. differs from that of D. crossotela by the stronger conical profile of the former. Moreover, the epirostrum of L. subgiganteus n. comb. bears two strongly incised dorsolateral grooves. Due to this feature, L. subgiganteus n. comb. has been formerly attributed to the genus Megateuthis . However, L. subgiganteus n. comb. differs from Megateuthis by the shape and features of its orthorostrum, which bears no grooves. The similarity of the orthorostra of L. meta n. comb. and L. subgiganteus n. comb. demonstrates their close affinities and their inclusion into a single genus.

A POSSIBLE SEXUAL DIMORPHISM

IN LOTHARINGIBELUS N. GEN.

Belemnites are supposed to show some degree of sexual dimorphism given that dimorphic traits are well documented in other cephalopods, such as ammonites and living coleoids ( Davis et al. 1996; Wilkin 2022). An example of a possible sexual dimorphism in belemnites has been described by Doyle (1985) from the Toarcian of Yorkshire. In that case the presence of an epirostrum has been interpreted as a sexual adaptation. This idea had already been advanced by earlier workers (d’Orbigny 1842-1851; Lissajous 1925). Schlegelmilch (1998) comments that it is “tempting to interpret these results as a sexual dimorphism but not necessarily so” and suggests studying further potentially dimorphic pairs, such as Dactyloteuthis similis and D. semistriata . Stevens et al. (2017) studied in detail the Cretaceous epirostrum-bearing belemnite Neohibolites minimus (Miller, 1826) (see also Spaeth 1971) and concluded that the interpretation of the epirostrum as a sexually selected character remains plausible. In a recent paper about the anatomy of the giant belemnite genus Megateuthis, Klug et al. (2024) conclude that “there is no hard evidence for sexual dimorphism in belemnites yet. Concerning the two large forms Megateuthis suevica and M. elliptica , their widely overlapping occurrence and their similar morphologies are remarkable. Such species pairs evoke the question for sexual dimorphism, which has been discussed for belemnites a few times […]”.

On the other hand, dimorphism in belemnites could also have been expressed in other ways than solely by differences in rostrum size and shape. For example, biometric methods were used by Delattre (1956) in Toarcian Odontobelus Naef, 1922 and Ippolitov (2006) in Middle and Late Jurassic Hibolithes Montfort, 1808 , in which the epirostrum is seldom present (e.g., H. duperroni Combémorel, 1988 ). Geochemical methods were used by McArthur et al. (2007), who showed significant differences within two types of rostra attributed to a single species. In Recent squids, Arkhipkin et al. (2015) evidenced an elongate structure, the “tail”, which facilitates the development of a more mobile adult phase in these coleoids; by analogy, the elongate epirostrum in extinct coleoids like the belemnites could have played a similar role. However, in some groups like Onykia spp. , the elongation of the body occurs within both males and females, but in other groups, Lycoteuthis Pfeffer, 1900 for instance, it occurs only amongst males. The dimorphic vs. adaptive nature of the epirostrum remains therefore still a question open to debate (see also Bandel & Spaeth 1988; Stevens et al. 2017). Another hypothesis was advanced based on well preserved soft-part belemnites from the German Posidonia shale; one specimen shows an enlarged (> 5 mm) hook (mega-onychites) at the base of the arm crown which was interpreted as sexual dimorphism ( Hauff 1985; Schlegelmilch 1998; Wilkin 2022). This hypothesis has been discarded by some workers ( Riegraf 1996), who argued that in recent coleoids large hooks would occur in both the females and the males. Opposed to this view, Stevens (2010) reported that in modern squids large hooks are developed during maturity and that their presence in males only hints at a reproductive rather predatory function, so it seems likely that fossil mega-hooks fulfilled a similar role. It is important, however, to note that such mega-hooks are known only in Jurassic belemnites ( Klug et al. 2024).

Regarding Lotharingibelus meta n. comb. and L. subgiganteus n. comb., we are undoubtedly in presence of a “dimorphic pair” similar to the one identified by Doyle (1985) for the genus Youngibelus (synonym of Cuspiteuthis ). Similar pairs have since then been identified in Early and early Middle Jurassic belemnites (Pliensbachian to Bajocian) ( Table 3). In none of those pairs was a sexual dimorphism proven, though the possibility cannot be ruled out. In the case of Lotharingibelus n. gen., it can further be noted that the ratio of rostra of L. meta n. comb. to L. subgiganteus n. comb. is c. 10 to 1. These data are based on the rostra that are currently present in public collections and need to be taken with great care as it is likely that there is a collection bias. For Cuspiteuthis, Doyle (1985) gave ratios of 1.1 and 1.2 for two localities. Given the data at hand, it is therefore difficult to draw a conclusion about the sexual dimorphism in Lotharingibelus n. gen. Further studies on the “dimorphic pairs” known so far ( Table 3) are needed to corroborate the hypothesis of sexual dimorphism, either linked with the development of an epirostrum or reflected by differences in size and form of the rostrum ( Ippolitov 2006).