taxonID	type	description	language	source
502287BEFF89D535FF49B1AE14D737D5.taxon	description	In contrast to Osmerus and Hypomesus, the cartilage did not stain well in Mallotus villosus. Nevertheless, it is clearly visible that there is a single, large CMC over the complete height of the diastema (Fig. 9 J). Together with the neighbouring hypural plates, this CMC supports the lowest ray of the upper lobe and the uppermost ray of the ventral lobe. The CMC is clearly wider than the hypural plates with anterodorsal and anteroventral grooves for fitting on the neighbouring hypural plates. Medially directed pegs on the articulating fin rays are absent.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF89D537FCD1B0EC126B32DA.taxon	description	The single adult specimen of Argyropelecus in this study did not stain well for cartilage (Fig. 11 D). However, we can present some data, because there are also two well-expressed CMCs. In this case, the upper one is larger than the lower one. The upper one is slightly bean-shaped in lateral view and brick-shaped when seen from the posterior side. The lower CMC is slightly bean-shaped laterally and ball-shaped in posterior view. Only the lower CMC has a slight notch on the diastemal side. The uppermost ray of the lower lobe articulates on the lower CMC. On the upper CMC there are two rays articulating: the lowest ray of the upper lobe on the ventral half of the CMC and the second lowest ray on the dorsal end of the CMC. Sternoptyx appears unique in having a large cartilage bordering the diastema posteriorly and large parts of the hypurals (see below under Development of median caudal cartilages; Fig. 25 G, H). In Maurolicus muelleri there are two rather small CMCs (Fig. 11 E) of which the upper one is missing in some specimens (Fig. 11 F). They are comma-shaped and, in contrast to most other CMCs, positioned in the rostro-caudal plane, not extending laterally. The width of the CMCs does not exceed the width of the hypural plates. The CMCs seem to be in anatomical association with the most median rays of the caudal lobes, but these rays seem not to depend on the CMCs in terms of their attachment, which equals that of the other caudal rays on the hypural plates.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF94D529FCC3B73E16C73749.taxon	description	In Vinciguerria lucetia there is also one single cartilage occupying the space of the CMCs between hypural 2 and hypural 3 (Fig. 13 C). A major part of the diastema is filled by bony lamellar outgrowths of hypural 3. Only the posterior part of the diastema is spared by the outgrowth and houses the single CMC (Fig. 13 C). It is irregularly shaped in lateral view with a horizontal area where the cartilage seems less dense. One might even think there is a dorsoventral separation. However, in posterior view it becomes obvious that there is only one single, doughnut-shaped cartilage (Fig. 13 D). The outline of the hole in the cartilage shines through in lateral view and accounts for the misleading separation line and the less dense cartilage in the horizontal area. The lowermost caudal fin ray of the upper lobe articulates with the dorsal half of the cartilage, whereas the uppermost caudal fin ray of the lower lobe articulates with only the ventral margin of the cartilage.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF95D52BFF49B6B816C33521.taxon	description	In Aristostomias xenostoma (Fig. 14 E, F) and Bathophilus vaillanti (Fig. 14 G, H) there are two prominent CMCs in the diastema. In both species the upper CMC is slightly smaller than the lower one and they are both roundish in lateral view. In latero-posterior view the upper CMC in A. xenostoma resembles a bean with the slightly concave side facing hypural 3 (Fig. 14 F). The lower CMC in A. xenostoma is roughly boomerang-shaped with blunt tips facing ventrally, therewith embracing the sides of hypural 2 with its lateral arms (Fig. 14 F). In B. vaillanti the CMCs are slightly bean-shaped in posterior view, embracing the edge of hypural 2 and hypural 3 with their concave side facing anteriorly (Fig. 14 H). The CMCs in A. xenostoma and B. vaillanti are connected by strong connective tissue (Fig. 14 H). In A. xenostoma there is no direct articulation between any caudal fin ray and the CMCs. The lowermost caudal ray of the upper lobe articulates with the ventral edge of hypural 3, whereas the uppermost caudal ray of the lower lobe articulates with hypural 2. In B. vaillanti (Fig. 14 G) the lowermost caudal ray of the upper lobe articulates with hypural 3 and the upper CMC, its proximal tip points ventrally, therewith embracing the upper CMC. The uppermost caudal ray of the lower lobe articulates with hypural 2 and the lower CMC, its proximal tip points dorsally, therewith embracing the lower CMC. There are no medial pegs on the caudal rays in A. xenostoma and B. vaillanti. The CMCs are only slightly overlapping the edges of the hypurals in width. Hypural 3 gains in width more dorsally; hypural 2 more ventrally and at that point the width of the CMCs and the width of the hypurals are about the same (Fig. 14 D, H). There are also two CMCs present in the diastema of Chauliodus sloani (Fig. 14 I – K). They are of similar size with the upper one being slightly larger. In lateral view the lower CMC is roundish, and when seen in posterior view its shape resembles a bar or handle about double the width of a hypural plate. It seems somehow related to the upper ray of the lower lobe, but there is little connective tissue. In lateral view the upper CMC has an upright ovoid outline, but when seen from posterior side, its strongly curved, bean-like shape becomes visible. The concave part of the ‘ bean’ is facing ventrally towards the diastema. Two rays are articulating on this cartilage: in its lower half the lowest ray of the upper lobe and at its dorsal tip the penultimate ray of the upper lobe. None of the fin-ray bases show medially directed pegs. In Grammatostomias dentatus there are two small CMCs (Fig. 14 L). The upper CMC is bigger than the lower one, cordate in posterior view and with the tip pointing ventrally. The lower CMC is bean-shaped in posterior view, with its concave facet directed towards hypural 2. Neither cartilage has a direct articulation with caudal fin rays. In Eustomias obscurus the upper and lower CMCs are roundish in lateral view and V-shaped in posterior view (Fig. 14 M). In the upper CMC, which is smaller than the lower one, it becomes evident in posterior view that the left and right parts of the V are separate and not fused, thus actually representing two, bilateral cartilages. The CMCs are connected by a strong ligament (Fig. 14 M) and have no direct articulation with caudal fin rays. In Photonectes albipennis there is only a single CMC (Fig. 14 N), resembling the lower CMC in Chauliodus. It is positioned like a cap on the inner distal edge of hypural 2. An association with the uppermost ray of the lower lobe seems not very tight, if present at all. CMCs are absent in Malacosteus australis (Fig. 14 O) and Stomias boa (Fig. 14 P). Here the interior most rays of the caudal lobes articulate with hypural 2 and hypural 3, respectively.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF91D52DFF49B5EA12E23584.taxon	description	In Trachinocephalus myops a diastema is well visible, but there are no CMCs (Fig. 18 C). The lowest ray of the upper caudal lobe articulates directly in the diastema, but without cartilaginous support (Fig. 18 C). In Harpadon microchir the distal part of hypural 3 has a laminar extension that restricts the diastema caudally. There are also no CMCs present.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF91D52EFCD1B7F915B837CF.taxon	description	The situation is principally the same in other myctophid species (Fig. 19 C – F). In Lampadena speculigera there are small medially directed pegs in the interior-most fin rays of the caudal lobes. In Lampanyctus crocodilus the tips of the bracketshaped CMCs are elongated bridging a major part of the diastema (Fig. 19 D, E). In Diaphus watasei and Symbolophorus veranyi (Fig. 19 F) the CMCs are triangular in lateral view. In some specimens (not depicted here), there are very small bean-shaped accessory cartilages directly anterior to the CMCs.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
502287BEFF93D522FCD1B47516A93238.taxon	description	SIZE OF DIASTEMA AND PRESENCE OF MEDIAN CAUDAL CARTILAGES Some species show highly specialized caudal fins without any diastemal gap. However, most species have a diastema, but not necessarily cartilaginous structures in that area. Thirty-two individuals of 27 species with CMCs and 25 individuals of 25 species without CMCs were measured to examine the size relationships of the diastema and its cartilages, if present (Fig. 23; see Fig. 1 for measuring method). In specimens with CMCs, the size of the diastema ranged between 2.7 and 23.4 % of the total hypural height, with an average of 13.0 %. In specimens without CMCs, the diastemal gap ranged from 8.0 to 29.7 %, with an average of 15.9 %. There is no functional relationship between size of the diastema and presence / absence of CMCs among teleosts. DEVELOPMENT OF MEDIAL CAUDAL CARTILAGES Little information on the development of CMCs can be currently presented. Most information is available for salmoniform species (Fig. 24 A – I). Here, the single or two CMCs develop relatively late in comparison to other elements of the caudal fin. All hypurals are at least partly ossified before the first traces of CMCs appear (Fig. 24 B, E, H). This happens in Salmo and Thymallus shortly before the ural centra form. In Coregonus the two ural centra are already present when the first trace of a CMC appears (Fig. 24 H). First appearance of CMCs happens in Coregonus at about 27 – 30 mm SL, in Thymallus and Salmo between 19 and 25 mm SL. The CMCs form as a new structure in the diastema and do not originate as part of the hypural cartilages. They start as a small cartilage that grows during ontogeny (Fig. 24 B, C, E, F, H, I) until they reach their assumed final size, shape and place in the larger specimens depicted here. In cases where only one CMC develops, it appears in the ventral part of the diastema, close to the edge of hypural 2. The development of CMCs in Osmerus is similar (Fig. 24 J, K): they appear relatively late in comparison to other caudal fin elements. In Arctozenus risso juveniles of about 30 mm SL, the lower CMC is present in some specimens (Fig. 24 L), but not in all. It is formed as a simple bar embraced by the bases of the left and right hemitrich of the uppermost ray of the lower lobe. In many specimens of about the same size, no CMC is present, whereas in few, the upper CMC is present as a small ball between the bases of the lowest ray of the upper lobe. In the stomiid Photostomias the lower CMC appears between 21 and 32 mm SL (Fig. 25 A, B) and it develops before the upper CMC (Fig. 25 B). At this stage all hypurals are preformed of cartilage, but show no sign of ossification yet. There is one cartilaginous epural and the ossified uroneural, but there are no ossified vertebral centra. In a 92 mm SL specimen, all hypurals, caudal vertebrae and the single epural (with the tips still cartilaginous) are ossified, and two prominent CMCs are present in the diastema (Fig. 25 C). We lack intermediate developmental stages to determine the exact size at which the upper CMC appears. The same development of the CMCs during early ontogeny was observed in Astronesthes niger and Eustomias sp. (not illustrated here). In the phosichthyid Vinciguerria there is just a single CMC. This cartilage is present in a 9 mm SL specimen (Fig. 25 D). At this stage the hypurals have just started to ossify, but no ural centra are formed yet. In the sternoptychid genus Argyropelecus, the lower CMC develops before the upper CMC. At this stage (9.9 mm SL; Fig. 25 E) the hypurals, the parhypural and one ural centrum have already partly ossified. In our 13.3 mm SL specimen all caudal vertebrae have formed and the upper CMC is also present (Fig. 25 F). In the sternoptychid genus Sternoptyx there is one single, enlarged CMC. Our smallest specimen (8.8 mm SL) already shows this single cartilage (Fig. 25 G). At this stage the urostyle and hypurals already started to ossify. In a 9.5 mm SL specimen the single CMC has elongated in dorsoventral direction (Fig. 25 H). For the other investigated groups there is almost no information on the development available. In the smallest alepocephaliforms, sternoptychids and bathylagids available in this study, the CMCs are already present. In the smaller specimens of Polyipnus spinosus, the CMCs show a simpler, almost ball-like shape without the typical notch on the diastemal side found in bigger specimens.	en	Moritz, Timo, Buchert, Jan, Schnell, Nalani K (2019): Unexpected diversity of median caudal cartilages in teleosts. Zoological Journal of the Linnean Society 186 (3): 599-632, DOI: 10.1093/zoolinnean/zly094, URL: https://academic.oup.com/zoolinnean/article/186/3/599/5316022
