Vampyroteuthidae

 

1.  Arms
   • Arms II (probably) modified to form retractile filaments (see details below).
   • Lateral cirri present over arm length; suckers present only on distal half of arms where they alternate with cirri.
   • Suckers without cuticular lining; sucker stalks constricted distally to narrow plate at base of sucker.

     

2. Retractile filaments
   • Origin of the filaments:
     • The primitive (plesiomorphic) arrangement of arms in coleoid cephalopods is thought to be 10 equal arms. This arrangement is known in some fossil coleoids (belemnoids) and the presence of ten unequal arms in modern decapods is easily derived from such a condition. Therefore, octopods, with eight arms, have apparently lost one pair. If the vampire filaments represent modified arms II and if this is the pair that is lacking in octopods, then strong support would exist for a vampire-octopod affinity. Embryological evidence suggests that the missing arm pair in octopods is either arms II or III (Boletzky, 1978-79).
     • Pickford (e.g., 1940) concluded that the filaments were modified arms II based on their position in series with the arms, venous connections and innervation. Young (1967) clarified the innervation and argued that the filaments were not arms but homologues of the preocular tentacles of Nautilus. The axial nerves of arms send most of their fibers to the anterior subesophageal mass (brachial lobe) of the brain. Young found that the filament nerves bypass this lobe with efferent fibers arising from the middle subesophageal mass and the afferent fibers reaching an enlarged ventral magnocellular lobe. Dilly, et al. (1977), however, demonstated that large nerve bundles from the tentacles of the deep-sea squid Mastigoteuthis also pass to an enlarged ventral magnocellular lobe. Presumably the combined sensory function of thousands of suckers carried by the tentacles of Mastigoteuthis requires the large nerve bundle and the enlarged ventral magnocellular lobe. Similarly the still poorly understood functions of the filaments of Vampyroteuthis probably emphasized the connection to and size of the ventral magnocellular lobe while a loss of coordination with the principal arms resulted in a great reduction (at least) in the connection to the anterior subesophageal mass. As a result, the innervation of the filaments became a weak argument against filament-arm homology.
     • The homology of the filament appeared to be resolved when J. Z. Young (1977) reported a connection between the axial nerve of the vampire filament and ganglia of the circumoral commissure that connects the axial nerves of all arms. This evidence, however, could not be confirmed by Young and Vecchione (1996).
     • Recent confirmation of Pickford's earlier evidence (Pickford, 1946) that the vampire hatchling has relatively thick (i.e., more arm-like) filaments supports the homology between arms and filaments (Young and Vecchione, 1999)
     • 

       

     • The weight of evidence indicates that the filaments represent arms II. Proof may depend on examining the embryonic development of the vampire squid which is not feasible at present.
   • The filament:
     • Each long filament has muscles that run the along one side. Contraction of these muscles causes coiling of the filament and its retraction into the small filament pocket that lies at the base of the web. The following images show a filament that has been removed from a recently dead vampire. Most of the filament has an orange pigmentation; the cut base (arrow), however, is abruptly broader and has a pink color. Much of the tight coiling has been disrupted by handling.

       

     • Under the dissecting microscope numerous, straight "hairs" are seen extending from the filament. These "hairs" are thought to aid in capturing food.

       

     • The Histology of the filaments has been examined by Hoving and Robison, 2012. The "hairs" could not be detected in the paraffin-embedded sections but could be seen in SEM photographs collapsed onto the surface of the filament; there, they appear to be tree-like branching structures rather than simple hairs. The surface of the filament consists of a layer of "vacuolated" cells with little internal structure. In SEM photographs, these cells are also collapsed and the "hairs" seem to arise at the junctures between these cells. Beneath the vacuolated cell layer is a layer of simple cuboidal cells with larger cells broadly interspersed. These larger cells are apparently nerve cells as they have extensions that pass into a large, axial nerve. A large muscle exists along one side of the filament and its contraction results in the coiling of the filament.
     • The "hairs" apparently secure food particles (Hoving and Robison, 2012). The retraction of the filaments is a slow process and the vampire squid may swim to the portion of the tentacle holding the food (Hunt, 1996) and enclose it within the web. Next, the filament is drawn between the arms, wrapped in mucous produced by cells on the suckers, sucker stalks and cirri, and passed to the mouth (Hoving and Robison, 2012).
3. Head
   • Eyelid circular, without anterior optic sinus.
   • Beaks:
     • Lower beak:

       	V. infernalis, sex ?, 13 mm GL, 1.0 mm LRL, Hawaiian waters. Photographs by R. Young	V. infernalis, sex ?, ~40 mm ML, 2.2 mm LRL, Hawaiian waters. Photographs by R. Young.	V. infernalis, sex ?, ML ?, 5.3 mm LRL, Hawaiian waters. Photographs by R. Young.
       Side View
       Oblique View
       Oblique View
       “Top” view
       Oral view
       Front View
       Posterior Oblique View

     • About anaglyph 3D: Photographs here are in 3D, using anaglyph techniques which combines two photographs one in red and the other in cyan (blue + green) color. To get the 3D effect, you must use glasses with red and cyan lenses (filters) over your regular glasses. The form of the beak is far easier to interpret in 3D and we strongly recommend to the viewer that the glasses be obtained (this is especially helpful when viewing enlarged images - i.e. click on the image). These beak photographs were made using Red and Cyan Anachrome Aviator Glasses (see: http://www.anachrome.com/glassbuy.htm or http://www.amazon.com) which cost under $10.00 (USD).
     • Upper beak:

       	V. infernalis, sex ?, 13 mm GL, 1.0 mm LRL, Hawaiian waters. Photographs by R. Young	V. infernalis, sex ?, ~40 mm ML, 2.2 mm LRL, Hawaiian waters. Photographs by R. Young.	V. infernalis, sex ?, ML ?, 5.3 mm LRL, Hawaiian waters. Photographs by R. Young.
       Side View
       Oblique View
       Oblique View
       “Top” view
       Oral view
       Front View
       Posterior Oblique View

   • Nuchal cartilage present even though head and mantle broadly fused.
   • Central nervous system with incipient inferior frontal lobe system; superior buccal lobes adjacent (fused at edges) to posterior buccal lobes; suprabrachial commissure lies within brain.
4. Funnel
   • Funnel valve absent.
5. Mantle
   • Dorsal mantle cavity absent.
   • Mantle apex a highly-flexible muscular cone filled with gelatinous tissue located posterior to the cone of the gladius.
6. Fins
   • Two pairs of fins present during early ontogeny.
7. Spermatangia
   • Receptacle (deep sac) for spermatangia located anterior to each eye in females.
8. Shell
   • Shell a gladius with broad median field and broad conus with or without a short, narrow cyclindrical rostrum.
9. Photophores
   • Large circular, lidded organs (= "fin-base" organs or "large posterior photophores") present posterior to each adult fin .
   • Numerous small organs distributed over ventral surfaces of mantle, funnel, head and aboral surface of arms and web (="skin-nodule" organs or "epidermal photophores"). Two patches on dorsal surface of head look like aggregrated small photophores (see images in Introduction) but are photoreceptors (Herring, et al., 1994) and may be "Nuchal Organs" (see Parry, 2000).
   • Arm-tip organ(s) produce luminescent clouds consisting of microscopic glowing particles (Robison, et al., 2003).
   • Arm-tip organs that flash or glow (Hunt, 1996).
10. Pigmentation
    • Photographs, of the vampire squid, taken in situ at two different locations show the geographic differences in coloration:

      

    • These photographs of Vampyroteuthis were taken in situ by an ROV of the Monterey Bay Aquarium Research Institute. The two photographs were taken from widely different areas in the North Pacific showing geographic differences in coloration. The left image is a side view of the vampire in an unusual pose. Note the peculiar nature of the web in this posture which seems to suggest how the web can contract and expand. Also peculiar are the small epidermal photophores on the arms that seem to align in series. In the right image, the arms are aligned and the presence of a web is hardly noticed.
11. Viscera
    • Oviducal glands at terminal end of oviducts.
    • Visceropericardial coelom extends posteriorly as a slender duct, to a small organ at the apex of the conus of the gladius. This duct is possibly a remnant siphuncle.
    • Photosensitive vesicles located immediately dorsal to funnel and, possibly, on dorsal integument in nuchal region.

Comments: Mantle Cavity

  Ventral view of an immature, female V. infernalis with the mantle cavity of cut open. Posteriorly the lining of the mantle cavity has been cut away to better view the visceral nucleus. Note that there is no abdominal septum, no ink sac, no anal flaps. The visceropericardial coelom (dark region surrounding the ventricle, stomach and caecum) is large. Posteriorly, in the ventral midline, the mantle muscle terminates on the conus of the gladius. The photograph on the right shows a mature female. The arrangement of the viscera looks very different. The gladius, with a small rostrum and a dark "apical organ", is visible because surrounding tissue has been removed.