Automate

Anker, Arthur & Komai, Tomoyuki, 2004, Descriptions of two new species of alpheid shrimps from Japan and Australia, with notes on taxonomy of Automate De Man, Coronalpheus Wicksten and Bermudacaris Anker and Iliffe (Crustacea: Decapoda: Caridea), Journal of Natural History 38 (15), pp. 1895-1914 : 1907-1912

Relationships among Automate , Coronalpheus and Bermudacaris

As already mentioned, the taxonomy of the genus Automate is not satisfying, and the morphological diversity indicates that Automate is a quite heterogeneous

assemblage. The genus can be divided into three informal species groups by a number of morphological characters (summarized in table 1):

Automate dolichognatha species group, with two species, A. dolichognatha s. l. and A. talismani . The species group is characterized by: (1) rostrum not concealing eye-stalks, very short, triangular, not reaching to level of antero-lateral margin of carapace; (2) eye-stalks parallel and mesially juxtaposed; (3) ventro-mesial carina on first segment of antennular peduncle unarmed; (4) stylocerite usually not reaching distal margin of first segment of antennular peduncle; (5) scaphocerite somewhat reduced, not reaching distal margin of second segment of antennular peduncle; (6) second maxilliped without podobranch; (7) major chela oval or sub-rectangular in general outline; (8) propodus of third pereopod armed with spines; (9) dactyli of third to fifth pereopods simple, subconical; (10) uropodal endopod only slightly exceeding exopod; (11) diaeresis on uropodal exopod bearing dorsally two blunt teeth.

Automate evermanni species group, with five species, A. evermanni , A. rectifrons , A. rugosa , A. branchialis and A. anacanthopus . This species group is characterized by: (1) rostrum not concealing eye-stalks, very short, triangular, not reaching to level of lateral margins of frontal concavity, completely reduced in A. rectifrons ; (2) eye-stalks parallel and mesially juxtaposed; (3) ventro-mesial carina on first segment of antennular peduncle unarmed; (4) stylocerite not reaching distal margin of first segment of antennular peduncle; (5) scaphocerite somewhat reduced, not reaching distal margin of second segment of antennular peduncle; (6) second maxilliped with podobranch; (7) major chela variable in shape, more or less rounded in general outline, sometimes with inferior margin constricted, mesial face usually densely covered with anteriorly directed setae, fingers sometimes largely gaping; (8) propodus of third pereopod without spines, instead with long stiff setae; (9) dactyli of third to fifth pereopods subspatulate; (10) uropodal endopod only slightly exceeding exopod; (11) diaeresis on uropodal exopod devoid of teeth.

Automate hayashii species group, with presently two species included, A. salomoni and A. hayashii sp. nov. The inclusion of A. salomoni in the A. hayashii species group is tentative because of the incompleteness of the unique type specimen of A. salomoni . This species group can be defined by: (1) rostrum concealing at least most basal mesial portion of eye-stalks, broadly triangular ( A. hayashii sp. nov.) or triangular ( A. salomoni ), reaching or slightly overarching level of antero-lateral margin of carapace; (2) eye-stalks subparallel, with small antero-mesial tubercle in A. salomoni ; (3) ventro-mesial carina on first segment of antennular peduncle terminating anteriorly in acute tooth; (4) stylocerite overreaching distal margin of first segment of antennular peduncle; (5) antennal scaphocerite relatively well developed, reaching or nearly reaching distal margin of second segment of antennular peduncle; (6) second maxilliped without podobranch; (7) major chela more or less rounded in general outline (in A. hayashii sp. nov., unknown in A. salomoni ); (8) propodus of third pereopod armed with spines; (9) dactyli of third to fifth pereopods subconical; (10) uropodal endopod reaching far beyond exopod; (11) diaeresis on uropodal exopod with two blunt teeth.

Notably, Coronalpheus natator Wicksten, 1999 , the type species of the monotypic genus Coronalpheus Wicksten, 1999 , shares several characters with the A. hayashii species group (cf. figure 8 ). These characters include: triangular rostrum; ventro-mesial carina on basal segment of antennular peduncle terminating anteriorly in sharp tooth; scaphocerite not markedly reduced, reaching distal margin of second segment of antennular peduncle; uropodal endopod distinctly over-reaching exopod. Nevertheless, Coronalpheus natator differs from all Automate species in having the rostrum much more elongated ( figure 8A ); the eye-stalks clearly separated and divergent (not parallel and not mesially touching) ( figure 8A ); the antero-mesial angle of the eye-stalk bearing a conspicuous tubercle ( figure 8A, B ) (there is a similar, although much smaller tubercle at the same position in A. salomoni ); more slender chelipeds, with the carpi being more elongated, ventrally slightly excavated, fingers more slender, and the pollex of the major chela armed with a single, large tooth in adult males ( figure 8G, H ). These differences seem to warrant a full generic status for Coronalpheus . Furthermore, future phylogenetic study may eventually reveal that Automate is a non-monophyletic group; in this case the three informal species groups recognized herein could be considered as distinct genera.

At an earlier stage of this study, the presence of a row of small spines on the dorso-mesial margin of the first segment of the antennular peduncle in A. salomoni and A. hayashii sp. nov. appeared to be significant in suggesting a close relationship between A. hayashii species group and Coronalpheus . However, examination of several Automate specimens in the MNHN collections has shown that one to three homologous spines are present on the dorso-mesial margin of the first segment of the antennular peduncle in A. branchialis , A. anacanthopus , A. dolichognatha s. l., and also in Bermudacaris harti . Although in Coronalpheus natator these spines are much more developed and more numerous than in Automate (forming a peculiar row, cf. figure 8C, D ), this character should be not considered anymore as unique to Coronalpheus , as suggested by Wicksten (1999).

The absence of the appendix masculina in males in Automate is a feature generally believed to be of generic significance ( Chace, 1988; Wicksten, 1999). However, the absence of the appendix masculina in males has not been confirmed in A. salomoni and A. talismani . Although the holotype of A. hayashii sp. nov. lacks an appendix masculina, the presence of several flexible elongated setae typical of ovigerous females suggest that this specimen is a pre- or post-ovigerous female. Wicksten (1999) stated clearly that the appendix masculina is present in the males of C. natator . When the absence of the appendix masculina is confirmed for all species of Automate , this character will further support the generic separation between Automate and Coronalpheus .

Bermudacaris can be easily separated from Automate and Coronalpheus by the symmetrical chelipeds with the dactyli situated in the ventral position (~inverted). Bermudacaris harti , the type species, is a troglobitic species characterized by the reduced pigmentation of corneas, a feature that was included in the diagnosis of the genus ( Anker and Iliffe, 2000). Since B. australiensis sp. nov. has relatively wellpigmented corneas, the generic diagnosis given by Anker and Iliffe (2000) is slightly modified. The statement ‘corneal pigmentation reduced or absent’ is changed to ‘corneal pigmentation normal or reduced to small spot’. Anker and Iliffe (2000) noted that while the two paratype males had at least a small pigmented spot, the corneas of the holotype female were almost devoid of pigment. This raised the possibility of sexual dimorphism. Recently, two more specimens of B. harti mentioned as ‘not traced’ in the original description (cf. Anker and Iliffe, 2000: 765) were finally located in the USNM collections and examined by one of us (A.A.). One is an ovigerous female carrying four large eggs, and having a clear small pigment spot in the eye-stalks. A series of 11 specimens of B. harti was recently collected by T. Iliffe in the Deep Blue Cave, Bermuda (T. Iliffe, personal communication). Two of them, an adult non-ovigerous female and a juvenile specimen, both deposited in the collections of the MNHN, also have a small pigmented spot on each eye-stalk. This clearly rejects the sexual dimorphism in the eye-stalk pigmentation in B. harti ; the quasi-absence of pigmentation in the female holotype is simply due to more advanced destruction of the pigments in ethanol.

A single specimen, collected at low tide on the Grand Re«cif de Tule«ar (now Toliara) in the south-western part of Madagascar, referred to Automate dolichognatha by Ledoyer (1970), is very unusual for Automate . The first pereopods of Ledoyer’s specimen are equal or subequal in size (cf. Ledoyer, 1970: pl. 24B), with dactyli situated clearly in ventral position (cf. Ledoyer, 1970: pl. 18, the two figures depicting the cheliped are actually upside down), which is one of the characteristics of Bermudacaris . However, in all other respects (frontal region, third maxilliped, second pereopod, etc.) the specimen exhibits features typical of Automate . Unfortunately, our efforts to locate Ledoyer’s specimen in the collections of MNHN, the University of Marseilles and the Endoume Marine Station, France, were fruitless. Future collections of small alpheid shrimps in the Toliara region, south-western Madagascar, may result in a discovery of a new taxon, which appears to be intermediate between Automate and Bermudacaris .

Figures

FIG. 8. Coronalpheus natator Wicksten, 1999. Paratype, ovigerous female (CL 6.6 mm; USNM 287088). (A) Anterior part of carapace and eyes, dorsal view; (B) same, lateral view; (C) left antennular peduncle, ventro-mesial view; (D) same, dorso-mesial view; (E) left antenna, dorsal view; (F) ultimate segment of right third maxilliped, lateral view; (G) major left cheliped, lateral view; (H) same, carpus and chela, mesial view; (I) right third pereopod, lateral view; (J) dactylus and distal part of propodus of fifth pereopod, mesial view; (K) exopod of left uropod, dorsal or ventral view. Scales: 1 mm.