Details on "Megalosaurus" monasterii

Here's a post about a theropod taxon so obscure it really doesn't have a presence on the web besides brief parroting of the largely inaccurate information in Carrano et al.'s tetanuran paper (even on The Theropod Database) and which has never really been combined in the literature either.  Gerke and Wings (2016) provided the obvious launching point and was invaluable for correlating information.

It differs a bit in structure from The Theropod Database format in that all referred specimens are given entries even if wrongly referred.  Those wrongly referred have an X in front of their specimen entry, and Gerke and Wang's Morphotype for each specimen is given at the end of their entry.  I figured this was the most condensed way to contain all proposed monasterii information, but the upcoming Database entries will be divided between higher taxon pages as usual.

"Megalosaurus" monasterii (Münster, 1836) Struckmann, 1878
= Saurocephalus monasterii Münster, 1836
?= Saurocephalus münsteri von Meyer vide Struckmann, 1871
?= Saurocephalus muensteri von Meyer vide Brauns, 1874 emmend.

Etymologies- "we now also owe the knowledge of another new species from the upper Jurassic layers near Linden to the zeal of my brother, who has been trying for many years to find rare, previously unknown fossils and to make them available for scientific use; just as he has also discovered ... the fish remains made known in this treatise ... . I therefore have no qualms about naming this new fish after him" (translated). Latin monastērium means monastery, yet Münster describes his "brother Wilhelm" as "chief of the Garde du Corps Regiment in Hanover", a military position as opposed to a religious one.
muensteri after German paleontologist Count Georg Ludwig Friedrich Wilhelm zu Münster who first described Saurocephalus monasterii, or after his brother Wilhelm Münster who he named the species after (see below).

Late Kimmeridgian, Late Jurassic
Ahlem (or Lindener Berg?), Mittlerer or Oberer Kimmeridge, Lower Saxony, Germany
Holotype- (NLMH101375a; = Struckmann coll.; as Saurocephalus münsteri) incomplete tooth (28.3x14.4x7.6 mm) I
Late Kimmeridgian, Late Jurassic
Ahlem, Mittlerer Kimmeridge, Lower Saxony, Germany
Referred- X(NLMH101375b; = Struckmann coll.; as Saurocephalus münsteri) incomplete tooth (42x20.5x10 mm) (Struckmann, 1871) B
Late Kimmeridgian, Late Jurassic
Ahlem, Oberer Kimmeridge, Lower Saxony, Germany
X(NLMH101377; = Struckmann coll.) incomplete tooth (25.3x14.8x6.2 mm) (Gerke and Wings, 2016) C
Late Kimmeridgian, Late Jurassic
Holzen/Ith, Mittlerer or Oberer Kimmeridge, Lower Saxony, Germany
X(GZG.V.010.333) tooth (77x31.5x17.8 mm) (Royo y Gómez in García, Chillón and Ortega, 2009) A
Late Kimmeridgian, Late Jurassic
Kahlberg, Oberer Kimmeridge, Lower Saxony, Germany
X(GZG.V.010.334) tooth (37.3x19x11.4 mm) (Smith, 1893) K
Late Kimmeridgian, Late Jurassic
Lindener Berg, Mittlerer or Oberer Kimmeridge, Lower Saxony, Germany
?(GZG.V.010.319) incomplete tooth (29.4x14.5x8 mm) (Gerke and Wings, 2016) I
?(GZG.V.010.327) tooth (27.9x12/6x6.2 mm) (Gerke and Wings, 2016) I
Early Kimmeridgian, Late Jurassic
Marienhagen, Unterer Kimmeridge, Lower Saxony, Germany
X(RPM.NKP.14356) tooth (57x26.8x?13 mm) (Gerke and Wings, 2016) B
Oxfordian, Late Jurassic
Marienhagen, Korallenoolith, Lower Saxony, Germany
X(GZG.V.010.381) incomplete tooth (45x22.8x10.5 mm) (Wichmann, 1907) B
Late Kimmeridgian, Late Jurassic
Tönniesberg, Mittlerer Kimmeridge, Lower Saxony, Germany
?(MNCN 84; = ACN239/005) tooth (García, Chillón and Ortega, 2009)
?(MNCN 85; = ACN277/012) tooth (García, Chillón and Ortega, 2009)
X(NLMH101376a; = Struckmann coll.; as Saurocephalus münsteri) incomplete tooth (23.5x13.8x6.4 mm) (Struckmann, 1872) C
X(NLMH101376b; = Struckmann coll.; as Saurocephalus münsteri) tooth (15.7x8.4x6.3 mm) (Struckmann, 1872) G
?(NLMH101376c; = Struckmann coll.; as Saurocephalus münsteri) tooth (25.5x11.8x6.1 mm) (Struckmann, 1872) I
X(NLMH101376d; = Struckmann coll.; as Saurocephalus münsteri) tooth (16x9.9x5.3 mm) (Struckmann, 1872) G
X(NLMH101376e; = Struckmann coll.; as Saurocephalus münsteri) incomplete tooth (10.5x6.2x4.4 mm) (Struckmann, 1872) G
X(NLMH101378a; Struckmann coll.) tooth (21.1x11.1x8 mm) (Struckmann, 1878) G
X(NLMH101378b; Struckmann coll.) tooth (19.8x11x6.5 mm) (Struckmann, 1878) F
X(NLMH101378c; Struckmann coll.) tooth (14x9.3x5.8 mm) (Struckmann, 1878) E
X(NLMH101380a; Struckmann coll.) tooth (20.2x11.5x6.7 mm) (Struckmann, 1878) F
X(NLMH101380b; Struckmann coll.) tooth (14.7x7.7x5 mm) (Struckmann, 1878) F
X(NLMH101380e; Struckmann coll.) tooth (15x10x6 mm) (Struckmann, 1878) E
?(NLMH16416c; = Dahl coll.) partial tooth (?x14.4x8 mm) (Gerke and Wings, 2016) I
?(RPM.NKP.14357) tooth (39x15.8x?8.6 mm) (Gerke and Wings, 2016) I
X(RPM.NKP.14358) tooth (21.8x12.5x7.5 mm) (Gerke and Wings, 2016) G
(XRPM.NKP.14359) incomplete tooth (10.8x8.5x4.5 mm) (Gerke and Wings, 2016) E
?(University of Marburg coll.) four teeth (11 mm) (Royo y Gómez in García, Chillón and Ortega, 2009)

Diagnosis- (after Gerke and Wings, 2016) lateral teeth similar to Sinraptor dongi except- base lancleolate instead of 8-shaped; distal carinae not twisted in distal view.

Comments- Gerke and Wings (2016) are the only authors to examine "Megalosaurus" monasterii in a modern context. They refer the holotype (NLMH101375a) to their Morphotype I, along with GZG.V.010.319, GZG.V.010.327, NLMH101376c, NLMH16416c and probably RPM.NKP.14357. They note "The cladistic analysis places morphotype I within Allosauroidea close to teeth of Sinraptor", although "several differences exist, such as the outline of the basal cross-section and the rather straight and non-twisted distal carinae in distal view." Furthermore, "The DFA results classify GZG.V.010.319 (41.08%) and NLMH101375a (45.34%) as Neovenator and GZG.V.010.327 (49.49%), NLMH101376c (with CBR instead of MC 17.12%) and RPM.NKP.14357 (39.77%) as Erectopus. The DFA results support therefore the assignment of the cladistic analysis of morphotype I to Allosauroidea." Among named Late Jurassic European allosauroids, Metriacanthosaurus is known from slightly earlier Oxfordian sediments in England but preserves no dental remains, while Allosaurus and Lusovenator are known from comparably aged Kimmeridgian deposits in Portugal. Morphotype I teeth did not match closely with Allosaurus (DFA 0.00%), so Lusovenator which lacks preserved teeth but is a basal carcharodontosaurid like Neovenator might be a good candidate.

"Megalosaurus" monasterii Morphotype I teeth. A- GZG.V.919.319 in (1) labial and (2) distal views. B- GZG.V.010.327 in (1) distal and 2 (mesial) views; (3) distal carina. C- holotype NLMH101375a in (1) labial and (2) distal views. D- NLMH101376c in (1) distal and (2) basal views. E- RPM.NKP14357 in (1) labial view. (after Gerke and Wings, 2016)

History and referred specimens- Münster (1836) initially referred the holotype tooth to Saurocephalus, placed by him in the [super]family Sphyraenoidea (today sphyraenids are classified as carangiform percomorphs) but today recognized as a saurodontid ichthyodectiform. He said "At first glance I thought I was looking at the tooth of a dinosaur, specifically Brachytaenius perennis, H. v. M. Fifth volume of contributions p. 22., to which it is very similar in size, external shape and markings, as well as in terms of the notched side edges" (translated), with Brachytaenis now being a junior synonym of Geosaurus giganteus. He thought it was different in exhibiting lingual curvature however- "There is ... a striking difference in the type of curvature of the tooth crown, which is ... curved ... from one side edge to the other towards the flat side." Münster further stated the tapered distal edge gave a drop-shaped cross section "almost like in the Saurocephalus inaequalis from the tertiary formations." That species is now a junior synonym of the sphyraenid Sphyreana substratus. He also wrote "the enamel shows ... a very faint, fine longitudinal maturation, which is intersected by delicate ring-shaped impressions, as in the Saurocephalus lanciformis" (the type species). Thus no differences from other supposed species of Saurocephalus were suggested. Munster wrote the tooth was collected at Lindener Berg by his brother and given to him.

Pictet and Campiche (1858) when describing Saurocephalus albensis noted that S. monasterii "perhaps does not belong to this genus" (translated).

Struckmann (1871) listed "Teeth of Saurocephalus Münsteri v. Meyer. Quite rare." (translated) collected by himself from the Middle Pteroceras layers of Ahlem. Based on Gerke and Wings' (2016) specimen table, this corresponds to two teeth (NLMH101375a, b) labeled Saurocephalus münsteri from the Struckmann collection from Ahlem. One of these (NLMH101375a) is the type of S. monasterii. Interestingly, Struckmann listed it under Reptilia instead of Pisces, perhaps presaging his decision to reassign the material seven years later.

Struckmann (1872) then listed "Saurocephalus Münsteri v. M" (under Pisces now) as being known as a "fairly common occurrence" of "individual teeth" from the Middle and Upper Pteroceras layers of Ahlem and Tönniesberg (translated). Based on Gerke and Wings' specimen table, this corresponds to five teeth (NLMH101376a-e) labeled Saurocephalus münsteri from the Struckmann collection from Tönniesberg. Brauns (1874) also mentioned "Saurocephalus Muensteri Meyer at Tönniesberge" from the Unterer Kimmeridge, which would be the valid spelling under the ICZN today (Article 32.5.2.1- "In the case of a diacritic or other mark, the mark concerned is deleted, except that in a name published before 1985 and based upon a German word, the umlaut sign is deleted from a vowel and the letter 'e' is to be inserted after that vowel"). Notably, these three 1870s references and Gerke and Wings' table depicting museum labels are the only records I could find of Saurocephalus münsteri/muensteri as opposed to S. monasterii. One might be tempted to blame a misunderstood spelling except all three historic references list von Meyer as the author instead of Münster. An in depth search has not located any publication by von Meyer naming S. münsteri, so whether it was validly proposed or an objective junior synonym of Saurocephalus monasterii is unknown. It certainly seemed to be understood as synonymous with S. monasterii since the two species were never listed in the same reference and given the same distribution in Struckmann's (1872 and 1878) tables. One distinct possibility is that it was a replacement name by von Meyer, perhaps because he thought it was more appropriate since Münster had named it or more understandably since Münster claims to have named it after his brother Wilhelm Münster. Thus von Meyer might have thought it was the species name Münster intended. The ICZN would not accept either rationale, but would not exist for another century and such replacement names were attempted in the 1800s (e.g. Zeuglodon for the non-reptilian Basilosaurus). Pending discovery of further documentation, Saurocephalus muensteri is here considered a junior synonym of Saurocephalus monasterii.

Struckmann (1878) listed "Megalosaurus (Saurocephalus) Monasterii Munster sp." (under Reptilia) as being known as a "fairly common occurrence" of "individual teeth" from the Mittlerer Kimmeridge Pteroceras layers (both the zone of Nerinea obtusa and the zone of Pteroceras oceani) of Ahlem and Tönniesberg (translated). This marks the first time the species had been placed in Megalosaurus, though no rationale is given. Six teeth (NLMH101378a-c, NLMH101390a-b, e) are listed as being labeled Megalosaurus monasterii from Struckmann's collection from Tönniesberg in Gerke and Wings' table that might correspond at least in part to these specimens. A final tooth (NLMH101377) from Gerke and Wings' specimen table is labeled Megalosaurus (Saurocephalus) monasterii from the Struckmann collection. It is from the Oberer Kimmeridge Virgula layers of Ahlem, which the taxon was marked as being unknown from in his 1878 publication, so the tooth would have been recognized after that.

Smith (1893) in his thesis lists "Megalosaurus Monasterii MNSTR." as being present at Kahlberg, which Gerke and Wings state "Following the collection label ("Megalosaurus monasterii, Late Kimmeridgian"), ... probably represent morphotype K (GZG.V.010.334) of this study." In Smith's table "List of fossils found on the Kahlberg in the Upper Jurassic" (translated) it is marked as being from the Lepidotus-Schichten which he placed above the Mittlerer Kimmeridge.

Woodward (1901) lists "Saurocephalus monasterii, G. von Münster, op. cit. pt. vii. (1846), p. 48, pl. iii. fig. 15.-Upper Jurassic; Linden, Hanover. [Probably Megalosaurian.]", which was referenced by Bardack and Sprinkle (1969) in their review of saurodontids.

Von Koenen et al. (1911) later mention Megalosaurus teeth "in Oxfordian sediments of the now abandoned quarry southwest of Marienhagen" (Gerke and Wings, 2016), which matches "Megalosaurus Monasterii Mnstr." reported by Wichmann (1907) from the Korallenoolith of the southern Roggesch quarry near Marienhagen. This is probably GZG.V.010.381 based on its label reading Oxfordian in Gerke and Wings' table.

Garcia et al. (2009) quoted from Royo y Gomez's (1924-1925) diary regarding a visit to the Geological Institute at the University of Marburg- "Megalosaurus monasterii Mst. Ob. Jura Tönjesberg (Hannover) (Saurocephalus id. id.), 6 teeth. They are from the same species that I have seen in Munich [Old Academy] and Frankfurt [Naturmuseum Senckenberg]. The largest ones are like those there and there are others that are no more than 11 mm long. They are indeed quite similar to ours [a destroyed tooth from the Weald of Benagéber] but they always have the anterior keel denticulated up to more than the lower half." They also write of this same diary- "At the Geological Institute in Göttingen (Germany), he also describes teeth that he cites as belonging to Megalosaurus monasterio (sic): "Huge tooth. The enamel is more than 80 mm long and the total tooth 10 mm. It has denticulated keels in the anterior part up to 15 mm from the base and in the posterior part all of it. 37 mm. of half circumference”." Based on these measurements and Gerke and Wings' table, this is almost certainly GZG.V.010.333, cataloged as Megalosaurus sp. in the GZG and with a crown height of 77 mm and mesial serrations ending ~16 mm from the enamel base. Finally, Garcia et al. say that donated to the MNCN "on January 25 by Prof. Wedekind, from the Geological Institute of Marburg, ... from the German Cretaceous, ... [are] two teeth from Hannover classified by him as Megalosaurus monasterii (ACN239/005; ACN277/012), currently MNCN 84 and MNCN 94." These seem likely to be two of the six teeth mentioned earlier, but the whereabouts of the other four are unknown.

Carrano et al. (2012) incorrectly said "Windolf (1997) transferred the taxon to Megalosaurus" when this had been done 119 years earlier by Struckmann (1878), and believed the holotype "tooth cannot be identified past the level of Theropoda indet." Note that while Carrano et al. say it originates "from the Oxfordian Korallenkalk", Struckmann (1871, 1872, 1878) and Brauns (1874) consistently placed the taxon in the Kimmeridgian layers, not the Oxfordian Korallenbank or Korallen-Oolite.

Gerke and Wings (2016) state "Following the collection label and figure presented by Graf Georg zu Münster, one tooth of morphotype I probably represents the specimen, possibly NLMH101375a, originally described as the fossil fish "Saurocephalus Monasterii"." Though reported as being from Lindener Berg by Munster, it was given to him by his brother instead of being collected personally with direct knowledge, so the museum label indicating the nearby locality of Ahlem may have been a later determination by e.g. Struckmann who had acquired the tooth for his collection and (1878) didn't list monasterii as being known from Lindener. Which locality is correct is likely lost to history as the preservation looks identical to both Ahlem (NLMH101375b) and Lindener Berg (GZG.V.010.319) teeth. Gerke and Wings assign the holotype to their Morphotype I. Their table also lists RPM.NKP.14356 from Marienhagen and RPM.NKP.14357-14359 from Tönniesberg as being labeled Megalosaurus monasterii in their museums' collections. Among teeth previously referred to monasterii/muensteri, Gerke and Wings identified some as their Morphotypes A (Megalosauridae), B (cf. Torvosaurus), C (Ceratosauria), E (cf. Tyrannosauroidea), F (basal Tyrannosauroidea), G (basal Tyrannosauroidea), I (Allosauroidea) and K (Allosaurus).

"Megalosaurus" monasterii holotype NLMH101375a in (a) lingual, (b) distal, (c) basal section and (d) close up of base in lingual view. (after Münster, 1836)

References- Münster, 1836. Ueber die im Korallenkalk das Lindner Berges bei Hannover vorkommenden Ueberreste von Fischen, mit Beschreibung und Abbildung einiger neuen Arten. In Münster and Wissman (eds.). Beitrage zur Petrefacten-Kunde. 7, 36-50.
Pictet and Campiche, 1858. Seconde Partie. Description des fossiles. In Pictet and Campiche, 1858-1860. Description des Fossiles du Terrain Cretace dees Environs de Sainte-Croix. Kessmann and Georg. 29-380.
Struckmann, 1871. Die Pteroceras-Schichten der Kimmeridge-Bildung bei Ahlem unweit Hannover. Zeitschrift Deutschen geologischen Gesellschaft. 23(1), 214-230.
Struckmann, 1872. Ueber die fossile Fauna des hannoverschen Jura-Meeres. Zweiundzwanzigster Jahresbericht der Naturhistorischen Gesellschaft zu Hannover. 21(1873). 29-71.
Brauns, 1874. Der obere Jura im nordwestlichen Deutschland von der oberen Grenze der Ornatenschichten bis zur Wealdbildung, mit besonderer Berücksichtigung seiner Molluskenfauna. Nebst Nachträgen zum unteren und mittleren Jura. Friedrich Vieweg and Son. 434 pp.
Struckmann, 1878. Der Obere Jura der Umgegend von Hannover. Hahn'sche Buchhandlung. 169 pp.
Smith, 1893. Die Jurabildungen des Kahlberges bei Echte. PhD thesis, Georg-August-Universität zu Göttingen. 71 pp.
Woodward, 1901. Catalogue of the Fossil Fishes in the British Museum (Natural History). Cromwell Road, S.W..Part IV. Containing the Actinpterygian Teleostomi of the Suborders Isospondyli (in part), Ostariophysi, Apodes, Percesoces, Hemibranchii, Acanthopterygii, and Anacanthini. British Museum of Natural History. 636 pp.
Wichmann, 1907. Der Korallenoolith und Kimmeridge im Gebiet des Selter und des Ith. Dieterich University. 39 pp.
von Koenen, Menzel and Schlunck, 1911. Geologische Karte von Preußen und benachbarten deutschen Ländern Lieferung 153: Blatt Gronau. Preußische Geologische Landesanstalt. [pp].
Bardack and Sprinkle, 1969. Morphology and relationships of saurocephalid fishes. Fieldiana Geology. 16, 297-340.
Windolf, 1997. Theropoden-Zähne aus dem Oberen Jura Niedersachsens. In Sachs, Rauhut and Weigert (eds.). Terra Nostra. 1. Treffen der deutschsprachigen Paläoherpetologen. Extended Abstracts. 33-34.
García, Chillón and Ortega, 2009. Contributions of José Royo y Gómez to the knowledge on the dinosaurs of Spain. Paleolusitana. 1, 339-364.
Carrano, Benson and Sampson, 2012. The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology. 10(2), 211-300.
Gerke and Wings, 2016. Multivariate and cladistic analyses of isolated teeth reveal sympatry of theropod dinosaurs in the Late Jurassic of northern Germany. PLoS ONE. 11(7), e0158334.