NEOPLECOSTOMINAE, Regan, 1904

Armbruster, Jonathan W., 2004, Phylogenetic relationships of the suckermouth armoured catfishes (Loricariidae) with emphasis on the Hypostominae and the Ancistrinae, Zoological Journal of the Linnean Society 141 (1), pp. 1-80 : 49

NEOPLECOSTOMINAE

I am recognizing an expanded Neoplecostominae that includes Hemipsilichthys , Isbrueckerichthys , Kronichthys , Neoplecostomus , and Pareiorhina despite the fact that these genera did not form a monophyletic group in this analysis. Hemipsilichthys , Isbrueckerichthys , Kronichthys , and Pareiorhina were placed in the Neoplecostominae by Gosline (1947), but have been placed in the Hypostominae since Isbrücker (1980). As the dataset presented herein evolved, the relationships of the genera of the Neoplecostominae were in flux because so few characteristics were found to help resolve them. In this final analysis, some of the genera ( Isbrueckerichthys and Pareiorhina ) formed a monophyletic group with Neoplecostomus , while Kronichthys and an undescribed genus ( Hemipsilichthys ?) formed a monophyletic group with the Hypoptopomatinae . Hemipsilichthys was sister to the remainder of the Neoplecostominae and Hypoptopomatinae . Montoya-Burgos et al. (1998) found support for a monophyletic Neoplecostominae minus Pareiorhina .

I have no confidence in the relationship of the genera of the Neoplecostominae and Hypoptopomatinae . Based on Gosline (1947) and Montoya-Burgos et al. (1998), and the fact that Hemipsilichthys , Isbrueckerichthys , Kronichthys , Neoplecostomus , and Pareiorhina definitely do not belong in the Hypostominae , the most conservative act is to place Hemipsilichthys , Isbrueckerichthys , Kronichthys , and Pareiorhina in the Neoplecostominae and await a study that will examine the relationships of these genera to each other and to the Hypoptopomatinae . The Neoplecostominae is currently being studied by Pereira and Reis.

Corymbophanes bahianus and typical Corymbophanes ( C. andersoni and C. kaiei ) are unrelated (Armbruster et al., 2000). Based on the phylogeny presented herein, C. bahianus is related to Hemipsilichthys while C. andersoni and C. kaiei are sisters to all other hypostomines. C. bahianus was transferred to Hemipsilichthys by Armbruster et al. (2000)

Despite the contention of Regan (1904) and Schaefer (1987), there is no support for Neoplecostomus as a basal hypostomine. Regan (1904) suggests that Neoplecostomus was close to Arges (= Astroblepus ) based on the presence of a plate-like lateropterygium (see 175); however, as mentioned in the character description above, the lateropterygium is shaped differently in Neoplecostomus and Astroblepus and the widened morphology is not likely to be homologous. Schaefer (1987) suggests one character that is synapomorphic for all loricariids minus Neoplecostomus - slender secondary radial elements in the pectoral-fin ray. However, the radial elements in callichthyids are also slender, and several loricariids have much wider elements than Astroblepus , suggesting that widened pectoral radial elements have evolved multiple times. Widened pectoral radial elements were not found to be useful in reconstructing the phylogeny of loricariids in this study.

Schaefer (1987) also suggests that Neoplecostomus lacks the characteristics he uses to diagnose all other loricariids; however, he states that a test of the phylogenetic position awaits examination of skeletal material. Neoplecostomus does have the characteristics Schaefer (1987: 21, fig. 15) provides as synapomorphies for Hypoptopomatinae + Loricariinae + Hypostominae + Ancistrinae .

Of the Neoplcostominae, Schaefer (1986) examined only Kronichthys , which he found to be the sister to Schizolecis (and incorrectly referred to as Pogonopomoides ) and this clade as sister to all other Hypostominae + Ancistrinae . In this study and in Schaefer (1991) Schizolecis is clearly a hypoptopomatine; a relationship between Kronichthys and the Hypoptopomatinae is certainly possible, given the results presented here. Kronichthys is also listed as examined in Schaefer (1987) and is considered to be a hypostomine; however, in the preparation of this study, the characteristics of Schaefer (1987) were re-examined in several taxa and Kronichthys has none of the characteristics that Schaefer used to diagnose the clade of Hypostominae + Ancistrinae .

Support for Neoplecostominae + Hypoptopomatinae ( Fig. 36 ) is moderately strong based on several synapomorphies, including (1) long anterior process of the fourth epibranchial (16: 1; Fig. 12B ), (2) a preopercular latero-sensory canal that proceeds posteriorly from the preopercle for a great distance (63: 1), and (3) a nasal capsule not completely supported ventrally (96: 1; Fig. 20C ; reversed in Neoplecostomus ). The most useful of these are 2 and 3 - characteristics possessed by no other loricariid examined.

There is congruence between this study and Montoya-Burgos et al. (1998) in the placement of Hemipsilichthys , Kronichthys , and Isbrueckerichthys with Neoplecostomus and the Hypoptopomatinae . In some analyses, Montoya-Burgos et al. obtain a monophyletic Neoplecostominae (minus Pareiorhina ); in all analyses they obtain a clade consisting of all of the genera of the Neoplecostominae and the Hypoptopomatinae .

Figures

Figure 12. Fourth epibranchial, right side, dorsal view (slightly twisted anteriorly). A, Pterygoplichthys multiradiatus, INHS 29787. B, Hemipsilichthys cameroni, USNM 279585. Scale bars = 0.5 mm. Shaded area is cartilage. Arrows indicate anterior processes.

Figure 20. Lateral ethmoid, right side, ventral view. A, Chaetostoma pearsei, INHS 345889. B, Delturus anguilicauda, USNM 318209. C, Hemipsilichthys sp., USNM 320377. D, Hypostomus unicolor, USNM 319355. Scale bars = 1 mm. Shaded area is cartilage. Dashed line indicates the extent of the nasal capsule.

Figure 36. Relationships of Astroblepus, Lithogenes, hypostomine tribes, and the nonhypostomine loricariids based on the ordered analysis. This is part of the strict consensus of 5098 most parsimonious trees of trees of 1328 steps, CI = 0.203, remainder of the consensus tree is in Figs 37 and 38. Numbers above the branches are clade numbers, numbers below are decay indices.