CLUPEIFORMES
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publication ID |
https://doi.org/ 10.1111/zoj.12142 |
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persistent identifier |
https://treatment.plazi.org/id/03DB6116-533A-A21C-FE15-D472272C799D |
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treatment provided by |
Marcus |
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scientific name |
CLUPEIFORMES |
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CLUPEIFORMES View in CoL View at ENA
Descriptions
Denticeps clupeoides ( Fig. 12 View Figure 12 )
The segmentum facialis lacks any subdivision and originates from the quadrate, symplectic, metapterygoid, hyomandibula, and preopercle. The lateral-most facial fibres insert onto the mandibular tendon and, based on positional correspondence, this muscle portion presumably corresponds to the ricto-malaris. The medialmost set of fibres of the segmentum facialis is slightly shorter than the lateral set and seems to be homolo- gous, at least in part, with the stegalis. These fibres converge to the meckelian tendon that, in turn, inserts on the coronomeckelian.
The ramus mandibularis trigeminus nerve passes external to the segmentum facialis.
At its origin, the segmentum mandibularis of Denticeps is well differentiated into three distinct sections. The coronalis and prementalis arise, respectively, from the dorsal and ventral regions of the mandibular tendon. The third section, the postmentalis, originates from a small faucal tendon that attaches to the anteromedial portion of the quadrate. As they continue anteriorly, all three of these mandibular sections progressively conjoin to a common single attachment onto the angulo-articular, dentary, and Meckel’s cartilage.
Pellona harroweri ( Fig. 13 View Figure 13 )
Sections within the segmentum facialis are more discernible in Pellona than in Denticeps . The rictomalaris of Pellona originates from the quadrate, symplectic, and hyomandibula and remains undivid- ed along most of its anteroposterior expanse. The dorsalmost fibres of the ricto-malaris, corresponding to the malaris, insert onto the coronoid area of the retrojugal lamina. This membrane is continuous ventrally with a short, but wide, mandibular tendon. Consequently, the fibres of the ricto-malaris become gradually attached ventrally to the mandibular tendon. The ventral set of fibres in the ricto-malaris attached to the mandibular tendon thus primarily corresponds to the rictalis.
Although not separate from the ricto-malaris, the stegalis is unequivocally distinguishable as a separate unit from a medial view given its more anterior origin from the metapterygoid. The stegalis converges onto the ventral portion of the intersegmental aponeurosis, primarily on the meckelian tendon that is anchored anteriorly to the coronomeckelian.
The ramus mandibularis trigeminus nerve passes lateral to the anterior portion of the segmentum facialis.
The segmentum mandibularis is not differentiated into subparts. This segment originates primarily from the mandibular tendon, although a few posteroventral fibres also arise from the meckelian tendon. Insertion of the segmentum mandibularis is onto the dentary, angulo-articular, and Meckel’s cartilage.
Remarks
Diogo & Doadrio (2008) described the adductor mandibulae of Denticeps clupeoides , one of the species of clupeiforms that we examined. According to their interpretation, this species bears only a single facial section that they identified as the A2 and lacks the other sections of the segmentum facialis commonly found in most other teleosts. Our observations of Denticeps clupeoides confirm the lack of obvious division in the segmentum facialis in this taxon ( Fig. 12 View Figure 12 ). Nonetheless, contra Diogo & Doadrio (2008), the evidence indicates that none of the other primary sections of the teleostean segmentum facialis is lost in this taxon, but rather that these sections are present albeit undifferentiated from each other. Supporting this hypothesis is the fact that the undivided segmentum facialis in Denticeps clupeoides exhibits the same basic origin, in- sertion, and position of the entire segmentum facialis of other teleosts that have more clearly discernible rictalis, malaris, and stegalis (see Datovo & Vari, 2013), including other members of the Clupeiformes , such as pristigasterids and clupeids (see below). Therefore, as is the case with the elopomorphs Elops and Megalops and the osteoglossomorph Hiodon discussed above, the segmentum facialis of Denticeps is formed by the three fundamental sections common across the Teleostei that are poorly differentiated from each other.
The adductor mandibulae in the Clupeidae greatly resembles the configuration encountered in the pristigasterid Pellona ( Fig. 13 View Figure 13 ), inasmuch as the segmentum facialis in both taxa is also primarily differentiated into two similar sets of fibres: a superficial set associated with both the segmentum mandibularis and the retrojugal lamina, which thus corresponds to the ricto-malaris; and an inner set of fibres directly attached to the lower jaw that clearly corresponds to the stegalis ( Eaton, 1935; Munshi, 1960; Wu & Shen, 2004). As in Pellona , the segmentum mandibularis in the Clupeidae is often reported to be mostly undivided ( Eaton, 1935; Van Dobben, 1935; Munshi, 1960; Wu & Shen, 2004).
Diogo & Doadrio (2008) also reported the existence of an Aω not differentiated into subparts that originated exclusively from the intersegmental aponeurosis in Denticeps clupeoides . Our observations of the same species conclusively demonstrate that the segmentum mandibularis can be differentiated at its origin into three sections. One of these, the postmentalis, which originates from the quadrate, was apparently overlooked by Diogo & Doadrio (2008; compare their fig. 3 with our Fig. 12B View Figure 12 ).
Synonymy
Segmentum facialis
A 2: Van Dobben (1935): Clupea .
A2: Diogo & Doadrio (2008): Denticeps .
Adductor mandibulae: Edgeworth (1935): Clupea .
Mandibularis: Munshi (1960): Hilsa ilisha (= Tenualosa ilisha ).
Pars ricto-malaris
A 1 A 2: Eaton (1935): Clupea .
A2: Wu & Shen (2004): Amblygaster , Nematalosa .
Adductor 1 or Ad 1: Munshi (1960): Hilsa ilisha (= Tenualosa ilisha ).
Pars stegalis
A 3: Eaton (1935): Clupea .
A3: Wu & Shen (2004): Amblygaster , Nematalosa .
Adductor 2 or Ad 2: Munshi (1960): Hilsa ilisha (= Tenualosa ilisha ).
Segmentum mandibularis
Aw or Aω or intramandibularis: Munshi (1960): Hilsa ilisha (= Tenualosa ilisha ).
Aw: Wu & Shen (2004): Amblygaster , Nematalosa .
Intramandibularis: Edgeworth (1935): Clupea .
Pars corono-prementalis Aω: Diogo & Doadrio (2008): Denticeps .
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