Belemnites - assorted favourites from my collection

[TqB]

Jumping for now from the end of the Lower Pliensbachian to the bottom of the next stage, the Toarcian (Upper Lias). Passaloteuthis is the dominant genus for a while - a typical belemnite of "average" shape and size (rarely more than about 13cm/5").

One characteristic of it (though shared with some other genera) is the pair of dorso-lateral furrows.

 

These Passaloteuthis bisulcata (Blainville, 1827) are from the Grey Shale Member, Whitby Mudstone Formation, of the north Yorkshire coast.

This member is notable for the frequent 3D preservation of the phragmocones - phragmocones are rare in most rocks. The actual preservation ranges from fairly soft (proto-nodule) to enclosed within a fully developed limestone nodule. The rostrum is always at least mostly outside the nodule.

 

specimen 1 - phragmocone in hard nodule (I really must finish prepping it!)

 

specimen 2 - no external nodule but still mostly 3D

 

specimen 3 - partial nodule 

 

The last two, showing the dorso-lateral furrow.

[Ludwigia]

Great samples with those phragmocones!

[TqB]

58 minutes ago, Ludwigia said:

Great samples with those phragmocones!

Thanks, Roger! It's actually quite hard to find a phragmocone with a whole belemnite attached, although that's down to having to wait for them to be exposed on the beach. Nodules with phragmocones inside are quite common as beach pebbles.

[Ruger9a]

OMG, that is really a nice specimen!  Thanks for sharing.

[Ludwigia]

2 hours ago, TqB said:

Thanks, Roger! It's actually quite hard to find a phragmocone with a whole belemnite attached, although that's down to having to wait for them to be exposed on the beach. Nodules with phragmocones inside are quite common as beach pebbles.

I believe you. I did manage to find at least a flattened and pyritized phragmocone attached to what I believe to be an Acrocoelites rostrum at Kettleness a few years ago.

 

 

[TqB]

12 hours ago, Ludwigia said:

I believe you. I did manage to find at least a flattened and pyritized phragmocone attached to what I believe to be an Acrocoelites rostrum at Kettleness a few years ago.

Nice, I think I remember that one. Acrocoelites coming up soon!

[TqB]

14 hours ago, Ruger9a said:

OMG, that is really a nice specimen!  Thanks for sharing.

Thank you! There are actually three separate ones there which isn't obvious - I'll edit it to make it clear.  

[AK hiker]

Thanks for the reference and to see whole specimens rather than bits and pieces gives me a clearer idea of what these fossils are. Bellamite pieces are closely associated with the ammonites I have found in the Talkeetna Mountains in Alaska.

[TqB]

On 04/06/2020 at 7:19 AM, AK hiker said:

Thanks for the reference and to see whole specimens rather than bits and pieces gives me a clearer idea of what these fossils are. Bellamite pieces are closely associated with the ammonites I have found in the Talkeetna Mountains in Alaska.

Thanks, glad it's useful. The word is "belemnite" by the way, from Greek "belemnon" = dart or javelin.

[TqB]

In the Yorkshire basin, the genus Passaloteuthis in my last post disappears below the top of the Grey Shale Member of the Whitby Mudstone Formation (Tenuicostatum Zone). This corresponds to the deepening waters and changing environment of the worldwide Toarcian Ocean Anoxic Event that is responsible for the much darker mudstones above.

The similar looking species Acrocoelites trisulculosus  (Simpson, 1855) appears a short way above the base of these, in the "Jet Rock" of the Mulgrave Shale Member, Serpentinum (Falciferum) Zone.

 

The most obvious difference is that Acrocoelites has an extra furrow - a ventral one - which appears for the first time at this level. Passaloteuthis only has the pair of dorso-lateral furrows. (Unfortunately, the ventral furrow is quite often not obvious or even absent in some specimens but an assemblage of a given population should show that it is the norm.)

 

A. trisulculosus rostra can be quite large - 220mm/8.5", possibly more.

 

Here's my longest, at about 195mm (depending on how much if the crushed alveolar rostrum you count). (The bulging bit is a portion of displaced phragmocone material that has cemented to the rostrum.)

 

This slightly shorter rostrum has a probably complete but flattened phragmocone. The whole specimen is about 310mm, just over 12". (The odd fin like feature is a bit of the keel of a Harpoceras, flattened out - its extended apertural rostrum, actually. It helps the provenance, as well as looking interesting!)

 

As an indication of how large the species can get, this is the largest piece of phragmocone of any belemnite that I have ever seen. It was a gift from a collector friend and must belong to one of the largest A. trisulculosus. (It's the only belemnite that is found in the bed.) I'd love to find a complete specimen of this size!

 

 

Here's a mock-up I did to show the probable full size, with a suitable 230mm Megateuthis and a smaller bit of Acrocoelites phragmocone in the gap. It comes to over half a metre.

 

Finally, just to demonstrate Acrocoelites grooves. Low angle light is often needed to show them up.

Dorso-lateral (lit from below to make it clearer):

 

And the characteristic ventral one - this is actually wider than the norm for the species:

 

 

 

Edited July 5, 2020 by TqB

[Natalie81]

Wauw! Keep posting them 

[TqB]

17 hours ago, Natalie81 said:

Wauw! Keep posting them 

Thanks, Natalie, plenty more to come.

 

I'll just add this here as it goes with the Acrocoelites trisulculosus in the last post.  

Megaonychites - one of the pair of specialised arm hooks that has been found in some belemnites.

The friend who found this has since seen a couple more eroded specimens in the same bed.

 

Full story in this post: Megaonychites

 

 

 

[TqB]

In Yorkshire, the next belemnite to appear in reasonable numbers after the Acrocoelites trisulculosus in the last posts is the large and elegant Acrocoelites inaequistriatus (Simpson, 1855). Serpentinum (Falciferum) Zone,  Falciferum Subzone.

 

It is actually rather scarce and finding one is always exciting. They are the first belemnites in the (Yorkshire) Toarcian to show an epirostrum - an extension of the "normal" orthorostrum, made of often rather ill defined layers which were possibly aragonitic and organic. These are subsequently covered by normal rostral calcite layers - the internal layers tend to be weak and/or dissolved away so the epirostrum is frequently crushed.

In this species, the outer calcite is usually quite thick and so largely 3D preservation is common.

 

A large specimen, fully 3D.  

 

View of the break near the apex, showing weakly laminated and strongly striated epirostral material in the centre surrounded by normal rostral laminations. (In some examples, the epirostral material is much more chaotic.)

 

A. inaequistriatus has three strongly marked grooves (ventral and dorso-lateral, as normal for the genus). It also has less marked parallel striations.

This is the ventral groove.

 

Another large specimen, this time with the epirostrum partially compressed. The extent of the normal rostrum is marked by the deflection at the 4" mark.

 

Strongly striated apex, with blister-like ornament - this is common in some epirostrid species.

 

Specimen where the epirostrum was lost prior to fossilisation (a common event).

 

 

 

 

 

Edited July 5, 2020 by TqB

[TqB]

This large, chunky one is a bit enigmatic. It's very rare and is the only complete specimen I have. (I have a badly eroded one that is probably the same.)

Probably Falciferum Subzone , bed 41 in Howarth's Yorkshire Upper Lias system. (That's above the Jet Rock for anyone who knows the area.)  It was given to me by a very kind collector friend and the stratigraphy is based on his description of the location.

(My damaged one is a from little higher, bed 43.)

 

It is the species called Belemnites validus Simpson 1855. In his work (The Fossils of the Yorkshire Lias), he identifies it as from beds corresponding to this subzone.

Simpson gives no figure but it was later figured in the classic Tate & Blake 1876, The Yorkshire Lias. For some reason, they place it in the previous zone - called "annulatus zone" at the time. now Tenuicostatum Zone (=Grey Shale Member). They list only three specimens and it's not clear if they collected any themselves or if they were all Simpson's.

 

In Doyle's 1990  monograph, "The British Toarcian (Lower Jurassic) Belemnites", he provisionally accepts Simpson's stratigraphy and regards it as probably an unusually fat variant of Acrocoelites trisulculosus,. He nominates a lectotype from Simpson's original material in the Whitby museum. (I really need to see if they have three specimens sometime.)

 

I'm not convinced it is A. trisulculosus. It seems too extreme in morphology (see photos) but admittedly this is based on very little material (two specimens really). The lectotype is much more Passaloteuthis/Parapassaloteuthis like, a view accepted by a couple of 20th century workers. There is a faint ventral furrow in mine which suggests Acrocoelites. So it's a tricky one and more material is needed, if possible! 

 

If Acrocoelites doesn't fit, a possible name for a revision would be Parapassaloteuthis validus.

 

Left lateral

 

Ventral

 

Compared with my fattest Acrocoelites trisulculosus below. 

 

Lectotype Belemnites validus (from Doyle, 1990, in Whitby museum.) Left lateral and ventral.

Edited July 5, 2020 by TqB

[Tidgy's Dad]

Fascinating stuff. 

[TqB]

On 19/06/2020 at 8:20 PM, Tidgy's Dad said:

Fascinating stuff. 

Thanks, Adam! Sorry for the late reply, I haven't looked at this for a while.

 

 

[TqB]

Still in the Falciferum Subzone of the Lower Toarcian, this is a good contender for most remarkable belemnite ever.  It's been a favourite of mine ever since I saw an illustration as a child, in the classic British Mesozoic Fossils handbook from the Natural History Museum (London). It was many years before I got the opportunity to collect any.

 

Cuspiteuthis tubularis (Young and Bird, 1822) from Yorkshire (also mainland Europe, possibly USSR though a lot of specimens I've seen have been wrongly assigned to it).

It's been assigned to various genera down the years - Belemnites originally as usual for the date, then Dactyloteuthis, Salpingoteuthis, Cuspiteuthis, Youngibelus and, most recently, Cuspiteuthis again.

 

It has an extremely long epirostrum which is usually crushed, though some specimens are solid.

A typical developed length is 20-25cm, over 30cm is rare.

 

In Yorkshire, they're common in maybe 2m of shale in the middle of the Falciferum Subzone (which here is about 23m thick). They require careful collecting, in several pieces always, and gluing them can be a challenge!

 

A largely uncrushed specimen, just over 30cm.

 

It shows a range of typical surface textures - ridges at the alveolar end:

 

and pustular ornament along the epirostrum:

 

Another specimen, just over 31cm. The epirostrum is entirely crushed and the much shorter, solid orthorostrum (about 10cm) is clear. This is the lateral view, it sank to the seabed on its side.

 

Dorsal view - this specimen was very fiddly to glue together.

 

Orthorostrum underneath thin epirostral sheath:

 

Striations on the epirostrum are typical:

 

A typical 250mm specimen but with phragmocone (detail obscured by pyrite crystals and an overgrowth of the inoceramid bivalve Pseudomytiloides dubius - a common situation.). 

 

Edited February 20, 2021 by TqB

[Ludwigia]

That last species is fascinating.

[Tidgy's Dad]

I agree with Roger. 

Also remember seeing it in British Mesozoic Fossils as a nipper. 

[TqB]

5 hours ago, Ludwigia said:

That last species is fascinating.

I agree! You get them (and similar species) at Holzmaden of course, and other localities - and the nomenclature has always been mixed up with Belemnites acuarius. Very slender Acrocoelites (probably gracilis) get called by this name sometimes - e.g. Taf. 8, fig. 7-8 in Schlegelmilch's Die Belemniten but they have no epirostrum.

 

3 hours ago, Tidgy's Dad said:

I agree with Roger. 

Also remember seeing it in British Mesozoic Fossils as a nipper. 

It was a wonderful book to grow up with! I used to imagine collecting an example of everything in it.

[TqB]

16 hours ago, Tidgy's Dad said:

Also remember seeing it in British Mesozoic Fossils as a nipper. 

I missed a chance to blow my own trumpet.  It gave me great pleasure to be asked to update the belemnite names for the latest edition, which came out in 2018. An honour for an amateur and a childhood dream come true.

Edited June 30, 2020 by TqB

[Tidgy's Dad]

7 hours ago, TqB said:

I missed a chance to blow my own trumpet.  It gave me great pleasure to be asked to update the belemnite names for the latest edition, which came out in 2018. An honour for an amateur and a childhood dream come true.

Congratulations. 

[TqB]

1 hour ago, Tidgy's Dad said:

Congratulations. 

Thank you, Adam!

[butchndad]

i know this is presumptuous to even ask as i'm sure you already have far better ones, but if you're interested in some (incomplete) specimens from Big Brook in NJ i would be happy top mail them to you (for free of course)

[TqB]

22 hours ago, RuMert said:

Incredible collection! Almost every entry surprises me

Thank you, glad you like them.

 

@butchndad Thank you very much, PM sent.