Promathildia Andreae, 1887

Gründel, Joachim & Nützel, Alexander, 2013, Evolution and classification of Mesozoic mathildoid gastropods, Acta Palaeontologica Polonica 58 (4), pp. 803-826 : 809-811

Genus Promathildia Andreae, 1887 (Synonym: Clathrobaculus Cossmann, 1912 )

Figs. 4A–C , 5A–C .

Type species: Mathilda janeti Cossmann, 1885 , here designated; Bathonian ; France .

Included species: There are certainly more than the here listed species, which belong to the genus Promathildia . However, descriptions and illustrations are commonly insufficient for a reasonable assignment. For the majority of the species listed below, the protoconch is unknown so that the placement of these species is also somewhat uncertain (the transaxial, strongly emerging protoconch is diagnostic). Included species: Cerithium amoenum Eudes−Deslongchamps, 1843 , Bajocian; Cerithium ziczac Eudes−Deslongchamps, 1843 (= type species of Clathrobaculus ), Pliensbachian; Turritella eucycla Hébert and Eudes−Deslongchamps, 1860 , Callovian; Turritella subulatissima Hébert and Eudes−Deslongchamps, 1860 , Callovian; Clathrobaculus fistulosus ( Stoliczka, 1861) , Sinemurian; Cerithium collenoti Martin, 1862 , Sinemurian; Cerithium sinemuriensis Martin, 1862 , Sinemurian; Mathilda janeti Cossmann, 1885 , Bathonian; Rigauxia gracilis Dareste de la Chavanne, 1912 , Hettangian; Promathildia (Clathrobaculus) doncieuxi Cossmann, 1913 , Oxfordian; Tricarilda plana with aberrant protoconch sensu Gründel 1997, Callovian; Clathrobaculus sp. , cf. eucyclus Hébert and Eudes−Deslongchamps, 1860 sensu Gründel 2000, Callovian;? Clathrobaculus ? humberti Martin sensu Gründel 2003b, Hettangian; Clathrobaculus sp. 1 sensu Kaim 2004, Valanginian;? Clathrobaculus sp. 2 sensu Kaim 2004, Callovian; Clathrobaculus sp. 3 sensu Kaim 2004, Bathonian; Clathrobaculus demissus Gründel, 2006 , late Bathonian;? Clathrobaculus medidilatatus Guzhov, 2007 , Oxfordian.

Spelling.—In the literature, both spelling variants, Promathildia and Promathilda are commonly used. Andreae (1887) introduced the genus as Promathildia . It was emendated to Promathilda because this name refers to the progenitor of the modern genus Mathilda Semper, 1865 ( Bieler 1995). However, Phillippe Bouchet (personal communication 2010) pointed out to us that the emendation Mathildia dates from Bosquet (1869): “This suggests that the spelling Promathildia is not an original incorrect spelling but that Andreae voluntarily used the emendation Mathildia combined with the prefix Pro −.”

Emended diagnosis.—Shell slender, relatively large, with many whorls; protoconch heterostrophic, transaxial, distinctly emerged, detached or almost detached from initial teleoconch whorl; teleoconch whorls with 3 (4) primary spiral ribs, convex with distinctly deepened suture, angulated at two of the primary spiral ribs (octagonal whorl outline) or with one of the primary spiral ribs as keel. Numerous fine axial ribs or strong growth lines; teleoconch ornament does not change during ontogeny or changes are only minor.

Remarks.— Promathildia is now included in Gordenellidae because Mathilda janeti is here designated as type species of this genus and this species is a gordenellid. Andreae (1887) introduced the genus Promathildia in a work on Late Jurassic (Oxfordian) gastropods from Alsace (east France). It was introduced as follows ( Andreae 1887: 23–24, translated from German): “The affiliation of certain Jurassic turritellid forms to the Recent genus Mathildia Semper was first recognized by Laube (1867) and again confirmed by Cossmann (1885) by the finding of inverse and perpendicularly situated embryonic whorls in Mathildia Janeti Coss. Anyhow , it seems conspicuous to us that the Jurassic mathildids (which could possibly be called Promathildia ) exceed their living relatives so

http://dx.doi.org/10.4202/app.2012.0052

eminently in size. As far as I can overview the Jurassic mathildids, they seem split into at least 2 morpho−groups. The more slender ones with pronounced reticulate ornament group around Mathildia Janeti Coss. , M. reticularis Piette etc. by almost lacking a siphonal outlet of the aperture. In the others, the spiral keels exceed the fine transverse ribs by far and its type is formed by M. binaria . These are broader and have a rather wide but flat anterior outlet of the aperture. According to this aperture shape, they resemble Messalia and Mesostoma . The latter Tertiary genus has also the same ornament. I am retaining these forms in Mathildia because I found one of the most important characters, the inverse embryonic end, in a good specimen from the Pfirt. Species related to M. binaria have commonly been assigned to Alaria as is the case in the previously mentioned species Alaria clathrata Terq. & Jourd. and Pterocera Cassiope d’Orbigny from the Oxfordian of Neuvizy, which was assigned to Alaria by Piette”. This citation shows that Promathildia was originally meant as a kind of chronotaxon encompassing the Jurassic mathildids which are allegedly larger than living members of Mathilda (size is the only diagnostic feature mentioned by Andreae 1887). It is clear that Andreae (1887) did not designate a type species for Promathildia and did not provide a sufficient diagnosis. He distinguished two morpho−groups within Promathildia but this is irrelevant for nomenclature because he did not name these groups. The designation of M. binaria as “ type ” for one of the unnamed subdivisions of Promathildia does not represent the designation of a type species because it relates not to a name bearing group. This is also true for Koken’s (1889: 458–459) treatment of Promathildia . This author repeated Andreae’s (1887) text verbally and as Andreae (1887), he did not name any of the two proposed subgroups of Promathildia . Andreae (1887) mentioned five nominate Jurassic species as members of Promathildia and one of those originally included taxa can be designated as type species:

– Mathilda janeti Cossmann, 1885 ,

– Mathilda reticularis ( Piette, 1855) ,

– Alaria clathrata Terquem and Jourdy, 1871 ,

– Turritella binaria Hébert and Eudes−Deslongchamps, 1860 – Pterocera cassiope Orbigny, 1850 .

Koken (1889) used the genus Promathildia for Triassic mathildoids including for “ Cerithium bisertum ” from the Cassian Formation. Kittl (1894) was the first to formally assign species (from the Triassic Cassian Formation) to the genus Promathildia in binominal form ( Nützel and Erwin 2004). Cossmann (1912) designated Cerithium bisertum Münster, 1841 from the Late Triassic Cassian Formation as type species of Promathildia . However, this designation is invalid because Cerithium bisertum has not been originally included by Andreae (1887) (ICZN article 67.6, 69.1, 69.2.2). Moreover, this species differs significantly from the Jurassic species that were mentioned by Andreae (1887) as examples for Promathildia . Thus this designation is in conflict with Andreae’s (1887) intention. In the following, we will discuss each of the originally included species as possible type species for Promathildia :

– Mathilda janeti Cossmann, 1885 ( Fig. 4A–C ) represents probably a species of the genus Clathrobaculus Cossmann, 1912 according to its overall morphology. Cossmann (1885: pl. 14: 20, 21) reported a heterostrophic protoconch of the Mathilda − type for M. janeti (see Fig. 4A herein); therefore this species is certainly a mathildoid. Obviously, Cossmann (1885) had only juvenile specimens at hand. The heterostrophic, transaxial protoconch and the slender shell of M. janeti would support an assignment to Clathrobaculus .

– Mathilda reticularis ( Piette, 1855) ( Fig. 4D, E ) was insufficiently described by Piette (1855) and no illustration was given. It was described and illustrated by Cossmann (1885). One specimen ( Cossmann 1885: pl. 17: 34; see Fig. 4E herein) is from the Piette’s (1855) collection and comes from the type locality (Rumigny, Bathonian) according to Cossmann. We designate this specimen as lectotype of

Mathilda reticularis . It is a teleoconch fragment which is 13.6 mm high. The whorl face is ornamented with four spiral ribs, two of which are more pronounced on the earliest preserved whorls. Protoconch, primary spirals on the early teleoconch, and aperture are unknown. Due to this incomplete preservation, it is not suitable as type species of Promathildia .

– Alaria clathrata Terquem and Jourdy, 1871 (Bathonian; Fig. 1E ) and Turritella binaria Hébert and Eudes−Deslongchamps, 1860 (Callovian; Fig. 1F ) closely resemble each other and both species are congeneric (see above). Both were repeatedly assigned to the genus Teretrina Cossmann, 1912 . Teretrina has a Triassic type species which differs significantly from both Jurassic species (AN and JG own observations) so that this generic assignment can be refuted. Alaria clathrata and Turritella binaria occupy a certain place within the Jurassic Mathildoidea (see below). The teleoconch of both species is relatively well known. However, protoconch and early teleoconch including primary spiral ribs have not been described or illustrated to this point. If one of these species would be chosen as type species of Promathildia , these important characters would remain unknown and therefore the status the genus would be unclear.

– Pterocera cassiope Orbigny, 1850 ( Fig. 4F ) (= nom. nov. pro Rostellaria bispinosa Phillips, 1829 ) (illustrated by Phillips 1829: pl. 4: 32 and Piette 1864 –91: pl. 35: 1–4, non pl. 1: 7, which probably is a Dicroloma or Bicorempterus species and insufficiently known). This species is not suitable as type species of Promathildia because many important characters are unknown and the species probably represents the caenogastropod family Aporrhaidae .

Andreae (1887) identified some of his Oxfordian specimens as Mathilda binaria ( Hébert and Eudes−Deslongchamps, 1860) , a species which was originally described from the Callovian of France. However, this is certainly a misidentification—there are strong differences in shape and ornament. For instance, Andreae’s (1887: pl. 1C: 1–3) illustrations show a hardly convex base bordered by a strong spiral rib so that the basal edge is angular. It probably represents an undescribed species of the genus Angulathilda . A description of a new species is not warranted yet because of the insufficient knowledge of this species. It is very likely that it represents a mathildid because Andreae (1887: 24) mentioned that the protoconch is heterostrophic.

In conclusion, of all species which were mentioned by Andreae (1887) when introducing the genus Promathildia , only Mathilda janeti is sufficiently known to characterize the genus. Therefore, we designate Mathilda janeti Cossmann, 1885 as a type species of Promathildia Andreae (1887) . This species is most probably congeneric with the type species of the genus Clathrobaculus Cossmann, 1912 ( Fig. 5A ) and therefore Clathrobaculus is a junior synonym of Promathildia . Promathildia janeti is slender, with numerous convex whorls separated by deep suture and has an ornament of two strong spiral ribs; the protoconch is relatively large and transaxial. These characters are also typical of Clathrobaculus ( Cossmann 1912; Guzhov 2007). The relatively small size of the originals of Mathilda janeti as illustrated by Cossmann (1885) probably indicates that he had only juveniles at hand. Our designation of a type species from those species which were originally included by Andreae (1887) changes the previous concept (e.g., Bandel 1995; Gründel 1997; Kaim 2004) and the genus should now be included in the family Gordenellidae Gründel, 2000 (see discussion of the Gordenellidae below); this group had its greatest diversity in the Jurassic.

The protoconch is known for the following species of Promathildia : Mathilda janeti Cossmann, 1885 (Bathonian), Tricarilda plana Gründel, 1973 with aberrant protoconch sensu Gründel 1997 (Callovian), Clathrobaculus sp. 3 sensu Kaim (2004) (Bathonian), and Clathrobaculus demissus Gründel, 2006 (Bathonian). All other species listed above have a teleoconch morphology which agrees with the diagnosis of Promathildia as given above.

Haas (1953) described several species from the Late Triassic and the transition to the Early Jurassic of Peru which closely resemble Promathildia . He assigned some of them to Clathrobaculus (see also Guzhov 2007), e.g., Promathildia (Teretrina) bolinoides Haas, 1953 , Promathildia (Teretrina) aculeata Haas, 1953 , and Promathildia (Clathrobaculus) subulata Haas, 1953 . For some of these species Haas (1953) could report a heterostrophic protoconch. However, these protoconchs cannot be evaluated from the illustrations provided by Haas (1953). According to their teleoconch morphology, it is very likely that these species belong to Promathildia or are closely related to this genus. Promathildia seems to be absent in the Late Triassic Cassian Formation; none of the species reported by Bandel (1995) seems to represent this genus.

Gordenella Gründel, 1990 differs from Promathildia in having straight to concave sides of mature teleoconch whorls. Moreover, in Gordenella the middle primary spiral is moving toward the abapical suture during ontogeny; at the same time, the primary spiral rib becomes weaker (in some cases it fades completely). Gordenella also differs in showing an ontogenetic weakening of the axial ribs.

Stratigraphic and geographic range.—The stratigraphic occurrence of Promathildia can only be given preliminarily, because many species which probably belong to this genus are insufficiently known. The oldest certain species is of Hettangian age ( Cerithium collenoti Martin, 1862 ). The genus is probably as old as Late Triassic. The last representative is of Early Cretaceous age ( Clathrobaculus sp. 1 sensu Kaim 2004). The genus is known from Germany, Austria, France, Poland,? Russia.

Figures

Fig 5. Type species and examples for the Jurassic genus Promathildia (family Gordenellidae) and protoconch of Falsoebala for comparison. A. Promathildia ziczac (Eudes−Deslongchamps, 1842), type species of Clathrobaculus, France, Early Jurassic; from Eudes−Deslongchamps (1843: pl. 11: 8, 9). Whole specimen (A1), last whorl enlarged (A2). B. Promathildia sp., cf. eucycla (Hébert and Eudes−Deslongchamps, 1860), erratic boulder from Vorpommern (NE Germany), Callovian; from Gründel (2000: pl. 1: 2). C. Promathildia sp., bore Usedom 3/63 (NE Germany), Late Bathonian, protoconch; from Gründel (1997: pl. 4: 48). D. Falsoebala compacta Gründel, 1998, bore Kłęby (formerly Klemmen) 1/37, Poland, Callovian, protoconch.

Fig. 4. Jurassic species originally included in Promathildia (family Gordenelllidae) (see also Fig. 1E, F). A–C. Mathilda janeti Cossmann, 1885 is designated as type species of Promathildia herein; Hérouvillette, France, late Bathonian. A. From Cossmann (1885: pl. 14: 20, 21), with protoconch in lateral (A1) and axial (A2) views. B. Last whorl with aperture; from Cossmann (1885: pl. 14: 19). C. Mathilda janeti Cossmann, 1885; from Cossmann (1885: pl. 14: 18). D. Mathilda reticularis (Piette, 1855), Le Wast, late Bathonian; from Cossmann (1885: pl. 8: 9). E. Mathilda reticularis (Piette, 1855), Rumigny, France, late Bathonian; from Cossmann (1885: pl. 17: 34), lectotype. F. Pterocera cassiope d’Orbigny, 1850, France, Oxfordian; from Piette (1864–91: pl. 35: 4).

Fig. 1. Type species and examples for Jurassic genera of the family Mathildididae. A. Mathilda angulata (Gründel, 1997), erratic boulder from Hohendorf near Wolgast 3/96/3, Germany, Callovian; from Gründel (1997: pl. 5: 73). B. Tangarilda subturritella (d’Orbigny, 1850), Kanonenberg near Halberstadt, Germany, Hettangian; from Gründel (2010: pl. 3: 3). C. Jurilda concava (Walther, 1951), borehole Kłęby (formerly Klemmen) 1/37, Poland, Bathonian; from Gründel (1997: pl. 1: 1). D. Tricarilda plana (Gründel, 1973), bore Kłęby (formerly Klemmen) 1/37, Poland, Callovian; from Gründel (1997: pl. 3: 41). E, F. The group of Turritella binaria (Jurilda or Tricarilda). These species were also originally included in Promathildia; see also Fig. 4. E. Alaria clathrata Terquem and Jourdy, 1871, Les Clapes, Bathonian; from Terquem and Jourdy (1871: pl. 4: 7). F. Turritella binaria Hébert and Eudes−Deslongchamps, 1860, La Motte Bourbon, early Callovian, Bayerische Staatssammlung für Paläontologie BSPG 2012 I 22.