STRENGERIANINAE RODRIGUEZ, 1982

Álvarez, Fernando, Ojeda, Juan Carlos, Souza-Carvalho, Edvanda, Villalobos, José Luis, Magalhães, Célio, Wehrtmann, Ingo S. & Mantelatto, Fernando L., 2020, Revision of the higher taxonomy of Neotropical freshwater crabs of the family Pseudothelphusidae, based on multigene and morphological analyses, Zoological Journal of the Linnean Society 193, pp. 973-1001 : 988-989

SUBFAMILY STRENGERIANINAE RODRIGUEZ, 1982 , NEW RANK lsid: urn:lsid:zoobank.org:act:C8D16D88-2E2E-4177-BBE2-CBDCD68CCBFB

Diagnosis (modified from Rodriguez, 1982; Campos, 2005): Anterolateral margin of carapace often finely serrate to unarmed, lateral armature indistinct. Exopod of third maxilliped not as long as, or slightly longer than, distal border of ischium; ratio exopod/ischium length ranging from 0.58 to 1.17. Opening of branchial efferent channel with jugal and lateral angles separated, in contact or almost in contact, closing aperture orifice. Gonopod long, slightly or evidently directed cephalically, lateromesially compressed, without lateral lobes on principal axis. Apical cavity rounded, next to mesial crest ( Chaceus ), or narrow and caudocephalically extended, surrounded by distal crests of three plates: mesial, lateral and marginal (Eidocamtophallus, Pallangothelphusa, Strengeriana ); field of apical spines in transversal position relative to principal axis, in distal or cephalic position; aperture of spermatic channel in mesocaudal position. Mesial process well developed, directed distally, acute or digitiform ( Chaceus ), or expanded and projected cephalically forming triangular or a complex dentate projection ( Strengeriana ), or divided into two lobes and projected cephalically (Pallangothelphusa), or as conical, acute tooth, projected cephalically (Eidocamtophallus). Marginal plate simple, overlapping caudal portion of mesialandlateralsurfaces,endingdistallyinapicalcavity; distal border straight or rounded (Eidocamtophallus, Pallangothelphusa, Strengeriana ), or projected over apex to form one of three apical elements ( Chaceus ). Row of long setae on proximal portion of marginal suture.

Type genus: Strengeriana Pretzmann, 1971 .

G e n e r a i n c l u d e d: C h a c e u s P r e t z m a n n, 1 9 7 1, Eidocamptophallus Rodríguez & Hobbs, 1989 , P h a l l a n g o t h e l p h u s a P r e t z m a n n, 1 9 6 5 a n d Strengeriana Pretzmann, 1971 .

Remarks: The gonopod type in this subfamily is based on those of the genera Phallangothelphusa and Strengeriana . Although no samples of Phallangothelphusa and Eidocamptophallus could be included in our molecular analysis, their gonopod morphology (see Rodriguez, 1982: 43, fig. 18; 121, fig. 78) clearly shows that they belong to this subfamily. Campos & Magalhães (2014) provisionally included Eidocamptophallus chacei in the Hypolobocerini after recognizing the difficulties in assessing their affinities with this or other tribes. It is herein suggested, however, placing this genus among the Strengerianinae due to the ornamentation of the apex of the gonopod bearing subapical spines on the lateral surface, in addition to the mesial process and the marginal tooth that are similar, although less developed, to the ornamentations of the gonopod of the species of Strengeriana .

Pending a future analysis including more species, Chaceus is placed in the Strengerianinae based on the morphology of the gonopod of C. turikensis ( Rodriguez & Herrera, 1994: 123, fig. 2A–E) and on an additional BI analysis (majority rule routine) where Chaceus and Strengeriana are sister genera ( Fig. 2 ). The members of this subfamily are distributed in Colombia and Venezuela.

Figures

Figure 2. Tree with divergence estimates for nodes of the main groups of the Pseudothelphusoidea (numbers at the nodes represent millions of years before present), with 95% confidence intervals represented by the grey bars. Three fossil crabs were incorporated into the analysis: (1) Hillius youngi Bishop, 1983, from the lower Cretaceous; (2) Tanzanonautes tuerkai Feldmann et al., 2007 in the Potamonautidae, from the Paleogene of Tanzania; and (3) an undetermined Trichodactylidae from the late Middle Paleocene of Peru (Klaus et al., 2017).