Hemmigrammopetersius, AND

Zanata, Angela M. & Vari, Richard P., 2005, The family Alestidae (Ostariophysi, Characiformes): a phylogenetic analysis of a trans-Atlantic clade, Zoological Journal of the Linnean Society 145 (1), pp. 1-144 : 110

( HEMMIGRAMMOPETERSIUS AND VIRILIA )

Diverse opinions about the relationships of Hemmigrammopetersius and Virilia have been advanced in the literature; but the hypothesis of their sister-group relationships arrived at in this study has not been proposed previously. In the case of Virilia , the unique species of the genus ( V. pabrensis ) was originally described within Phenacogrammus by Roman (1966). Subsequently, Roberts (1967b: 256) erected Virilia that included only P. pabrensis of Roman (1966). Roberts also suggested a close relationship of Virilia with Lepidarchus and Micralestes (presumably based on body size, sexual dimorphism and dentition).

Recently, Paugy (1990a: 80) proposed the synonymy of Virilia with Micralestes , together with the genera Hemmigrammopetersius , Rhabdalestes and Alestopetersius . Under Paugy’s scheme these five genera were brought together on the basis of the presence of a second row of inner dentary teeth. That character was, however, found to demonstrate a low level of consistency in this study (see also comments in character 88 concerning interspecific variation in this feature). Alternatively, Géry (1995: 46) discussed the sexual dimorphic anal-fin of Virilia and Rhabdalestes and proposed that those two genera should be synonymized based on the similarities that he observed in that body system.

Géry (1995: 46) also considered it appropriate to shift H. pulcher , the type species of Hemmigrammopetersius , into Phenacogrammus . Although H. pulcher was not examined in this study, the other two species of Hemmigrammopetersius incorporated in our analysis ( H. barnardi and H. intermedius ) are not closely related to Phenacogrammus within the final most parsimonious hypothesis of relationships. The results of our study, albeit based on hypothesized synapomorphies rather than overall similarity, parallel those of Géry (1995) in having Virilia and Rhabdalestes as closely related taxa. A more encompassing study involving all nominal species in Virilia and Rhabdalestes plus those of Hemmigrammopetersius must precede any change in the generic-level taxonomy of these taxa, as proposed by Géry (1995). Clade 30, formed by H. barnardi , H. intermedius and Virilia is defined by the following synapomorphies:

184. Inferior lamella of lateral ethmoid reduced and falling short of contact with vomer anteriorly (char. 27, 0> 1). Further modified in Virilia .

185. Lateral line distinctly reduced and with number of scales lacking laterosensory canal and pore greater than number of scales with those structures (char. 162, 0> 1). Also independently acquired in Phenacogrammus and clade 35.

The following features are ambiguously optimized for this clade:

186. Area of insertion of premaxillary-maxillary ligament on maxilla on anterior surface of maxilla (char. 66, 1> 0). Either derived at this level, reversed in Virilia and independently acquired in clade 35 with a reversal in Ladigesia , or independently acquired in Hemmigrammopetersius barnardi and H. intermedius and a synapomorphy for clade 35 that is reversed in Ladigesia .

187. More than four dentary teeth present (char. 84, 1> 0). Either derived at this level, reversed in H. barnardi and independently acquired in clades 32 and 35, or independently acquired in H. intermedius , Virilia and clades 32 and 35.

The relationships among H. barnardi , H. intermedius and Virilia remain unresolved in this analysis. H. barnardi is characterized by the following autapomorphies:

V 1. Third postcleithrum absent (char. 134, 0> 1).

V 2. Laterosensory canal in parietal absent (char. 157, 0> 1).

The following character is ambiguously optimized as an autapomorphy for this species:

V 3. Four dentary teeth present (char. 84, 0> 1)

H. intermedius is defined by two autapomorphies:

W 1. Medially directed, spine-like process on posttemporal present (char. 130, 1> 0).

W 2. Spine-like, medially directed process on medial surface of supracleithrum absent (char. 131, 1> 0).

Virilia is characterized by the following autapomorphies:

X 1. Inferior lamella of lateral ethmoid absent (char. 27, 1> 2).

X 2. Ridge on lateral surface of maxilla present (char. 76, 0> 1).

X 3. Relatively large inner row tooth proximate to dentary symphysis present (char. 88, 0> 1).

X 4. Distinct anteroposterior thickening of third unbranched anal-fin ray present and highly developed into anteriorly convex process (char. 183, 1> 2).

The following character is ambiguously optimized as an autapomorphy for this genus: X 5. Area of insertion of premaxillary-maxillary ligament on maxilla on lateral surface of maxilla (char. 66, 0> 1).