Calyptraeotheres Campos, 1990

Campos, Ernesto & Hernández-Ávila, Iván, 2010, Phylogeny of Calyptraeotheres Campos, 1990 (Crustacea, Decapoda, Brachyura, Pinnotheridae) with the description of C. pepeluisi new species from the tropical Mexican Pacific, Zootaxa 2691, pp. 41-52 : 44-45

Calyptraeotheres Campos, 1990

Type species. By original designation and monotypy Calyptraeotheres granti (Glassell, 1936) .Gender masculine.

Diagnosis. Female: Carapace arcuate anteriorly, anterolateral margin cristate; regions poorly defined, with 2 longitudinal cervical depressions from orbits to middle of carapace; front slightly projecting; MXP3 obliquely placed in buccal cavity; ischium, merus completely fused; palp 2- or 3-segmented; carpus larger than propodus; dactylus, when present, minute, inserted distoventrally on propodus; exopod with thin, unsegmented flagellum. WL1-3 of similar shapes; WL4 relatively more slender than others; propodi of WL 1and 2 with tuft of short stiff setae on distoventral margin; dactyli of WL 1‒3 similar in shape, those of WL 4 longest, sword-shaped. Abdomen covering thoracic sternum, with 6 abdominal somites and telson clearly separated.

Male: with carapace subpentagonal or suborbicular, regions poorly defined, dorsal region smooth, with short-spaced setae; anterolateral margin with fringe of simple setae. MXP3 similar to female. Abdomen with 6 somites, telson, well separated, widest at third somite, narrowing toward telson.

Distribution. Northeastern Pacific Ocean. C. granti : Mexico, throughout the Gulf of California and Magdalena Bay, west coast of Baja California Sur; C. pepeluisi new species: Michoacán, Mexico. Southeastern Pacific Ocean. C. politus: Ancón Bay , Perú to Castro, Chiloe I., Chile. Caribbean Sea. C. hernandezi: Cubagua I. , Venezuela. Southwestern Atlantic Ocean. C. garthi : Rio Grande do Sul, Brazil; Mar del Plata, Necochea, Golfo de San Matias, Argentina (see Campos 1990; 1999; Hernández & Campos 2006).

Hosts. Gastropoda: Calyptraeidea: Crepidula Lamarck, 1799 Calyptraea Lamarck, 1799 and Crucibulum Schumacher, 1917 (Campos 1990; 1999; Hernández & Campos 2006).

Remarks. While the taxonomy of the genus Calyptraeotheres has been well documented, its systematics and phylogenetic relationship have been a matter of debate (see Campos 1990, 1999; Hernández-Ávila & Campos 2006; Marques & Pohle 1995). Marques & Pohle (1995), in their phylogenetic analysis of the Pinnotheridae based on larval morphology, placed Pinnotheres politus (junior synonym of Caytraeotheres politus ) and Tumidotheres maculatus in their Pinnotheres -II group. They also concluded that both taxa were paraphyletic and transferred P. politus into Tumidotheres Campos, 1989 . Later, Campos (1999) re-analyzed the adult morphological traits on which Marques and Pohle (1995) based their conclusion and discovered that P. politus did not possess any of the diagnostic adult features of Tumidotheres (see, Campos 1989). Nevertheless, the adult morphology of both male and female P. politus concurred very well with that of Calyptraeotheres , and this species was finally included in this genus (see Campos, 1999). Palacios-Theil et al. (2009) subsequently performed a molecular analysis of selected members of the family Pinnotheridae to ascertain their phylogenetic relationships. Their results suggested a close phylogenetic relationship between Calyptraeotheres and Tumidotheres which, collectively with the genera Dissodactylus , Clypeasterophilus and Tunicotheres , formed the so-called clade-IIC of the Pinnotherinae sensu Palacios-Theil et al. (2009, Fig.1 ; but see discussion on this subfamily in Campos 2009). Our new analysis, on the updated matrix of Marquez & Pohle (1995), permitted to recognize that members of the genera Calyptraeotheres , Clypeasterophilus , Dissodactylus , Pinnaxodes Heller, 1865 and Tumidotheres (see Table 1, Pinnotherid V) share the larval characters analyzed and in general possess a very similar morphology. The larval morphology and molecular results suggest a closely relationship between Calyptraeotheres , Clypeasterophilus , Dissodactylus , and Tumidotheres but, these results mutually do not confirm the relationship of these genera with Tunicotheres and Pinnaxodes . Our results on larval morphology support a more closely relationship between the monotypic Tunicotheres and Pinnotheres taylori and in a less degree with members of the subfamily Pinnotherinae sensu Campos (2009) (see Fig. 1–2 ). Remarkably, Tunicotheres moseri and P. t a y l o r i share a similar kind of host (tunicates) ( Rathbun 1918; Campos 1996) and both have abbreviated larval development (see Hart 1935; Bolaños et al. 2004) which is highly derived. The systematics and classification of Pinnotheres taylori as well as of other crabs symbiotic of tunicates is currently under study by the first author, however, all the gathered morphological and ecological evidence suggest it, like Tunicotheres , neither belong in Pinnotheres nor in the subfamily Pinnotherinae sensu Campos (2009). The zoeae of this subfamily show a generalized and unique laterally convex telson with the furcal shafts greatly reduced to the size of the median projection and adults have a well developed protuberance on the basal antennal article (Campos 2009). Contrarily, the “tunicopinnos” have a telson subquadrate with two short lateral spines (see Hart 1935) and the antennal protuberance is absent (see Campos 1996). The discussion of the enigmatic molecular relationship between Tunicotheres and the Dissodactylus complex, is beyond the scope of the present paper, but probably this is the first documented molecular convergence within Pinnotheridea. Regarding Pinnaxodes , neither its adult morphology ( Campos et al., 1998; Takeda & Masahito 2000; Ng & Manning 2003) nor the molecular results suggest this genus is allied to Calyptraeotheres or other member of the clade IIC sensu PalaciosTheil et al (2009). We consider that the shared larval features between Pinnaxodes and other members of the Pinnotherid V group are probable homoplasies, like those observed in larvae of the Pinnixa -complex and Fabia- Juxtafabia (see Fig. 1 ; Palacios-Theil, et al. 2009: 457).

A preliminary analysis on selected adult morphological features of the carapace and third maxilliped of Calyptraeotheres suggests that is presumably more related to Dissodactylus and Clypeasterophilus than to Tumidotheres , although this would be in conflict with the molecular results of Palacios-Theil et al. (2009). The shared features between Calyptraeotheres and Dissodactylus - Clypeasterophilus include a glabrous subpentagonal-suborbicular carapace, and a third maxilliped with a fused ischium and merus and a carpus larger that the propodus in which, when present, a minute and rounded dactyl is inserted ( Griffith 1987; Campos & Griffith 1990; Campos 1990; 1999; Ng & Manning 2003; Hernandez-Avila & Campos 2006). Tumidotheres has a tumid and suborbicular carapare and its surface is covered with short, dense, and deciduous tomentum and the carpus of the third maxilliped is shorter that the large propodus in which the long, narrow and saptulate dactylus is medially inserted (see Campos 1989). We consider that this preliminary conclusion requires an extensive morphological comparative study between all genera cited here, but emphasizing non-adaptive features.

In spite of the uncertainty on the phylogenetic affinity of the Pinnotherid V group, the only conclusion that can be fully sustained until now from an adult morphological viewpoint, is that each genus remains valid, an opinion which is supported by several unique apomorphies that uphold the monophyly of each taxon ( Griffith 1987; Campos & Griffith 1990; Campos 1990; 1999; Campos et al. 1998; Takeda & Masahito 2000; Ng & Manning 2003; Hernandez-Avila & Campos 2006; Ocampo et al. 2010).

Figures

FIGURE 1. Strict consensus cladogram of 19 most parsimonious trees (length = 27 CI = 0.667; RI = 0.625; RC = 0.417) obtained from heuristic parsimony analyses of unweighted and unordered characters. Subfamily name as proposed by Campos (2009) is indicated. Pinnotherid I – V and Pinnixid I – II are explained in Table 1. Asthenognathus atlanticus was used as the outgroup. Numbers above branches are the percentage of 1,000 bootstrap replicates that support the relevant nodes.

FIGURE 2. Strict consensus cladogram of 13. 78 most parsimonious trees (length = 13.45 CI = 0.865; RI = 0.896; RC = 0.7751) obtained from heuristic parsimony analyses of unordered characters. The data were a posteriori reweighted using the rescaled consistency index (RC). Subfamily name as proposed by Campos (2009) is indicated. Pinnotherid I – V and Pinnixid I – II are explained in Table 1. Asthenognathus atlanticus (Varunidae) was used as the outgroup. Numbers above branches are the percentage of 1,000 bootstrap replicates that support the relevant nodes.