Expanding diversity in the mantis shrimps : two new genera from the eastern and western Paci c ( Crustacea : Stomatopoda : Squillidae )

Squillidae is the largest family in the Stomatopoda, with 47 genera to date. Phylogenetic analyses have shown Squilla Fabricius, 1787 and Oratosquilla Manning, 1968 to be paraor polyphyletic. Two poorly documented species within these genera, Squilla parva Bigelow, 1891 (eastern Pacifi c) and Oratosquilla kempi (Schmitt , 1931) (western Pacifi c) are not closely related to the respective type species of the genera in which they are currently placed. We herein redescribe S. parva and O. kempi based on type and other material, and propose two new genera for their reception, increasing the number of squillid genera to 49. key words Squilloidea, new genus, mantis shrimp, Indo-West Pacifi c, Atlanto-East Pacifi c. original article CORRESPONDING AUTHOR Shane T. Ahyong shane.ahyong@austmus.gov.au SUBMITTED 19 December 2016 ACCEPTED 10 February 2017 PUBLISHED 8 May 2017 Guest Editor Célio Magalhães DOI 10.1590/2358-2936e2017012 This article is part of the tribute offered by the Brazilian Crustacean Society in memoriam of Michael Türkay for his outstanding contribution to Carcinology Van Der Wal and Ahyong 2 New mantis shrimp genera Diagramação e XML SciELO Publishing Schema: www.editoraletra1.com Nauplius, 25: 2017012 IntroductIon Until the latter half of the 20th century, most species of Stomatopoda were included in the genus Squilla Fabricius, 1787, family Squillidae Latreille, 1802. In a major revision of Squillidae, Manning (1968) restricted the genus Squilla to species occurring in the AtlantoEast Pacific regions and erected numerous new genera to accommodate the Indo-West Pacific species as well as several Atlanto-East Pacific species. Significant subsequent revisions to Squillidae have recognized a total of 47 genera to date (Manning and Camp, 1983; Manning, 1995; Manning and Heard, 1997; Ahyong, 2001; 2013). Comprehensive phylogenetic analyses of the Squillidae recognized several generic groups within the family (Ahyong, 2005) and corroborated speculation by Manning and Camp (1983) and Manning and Heard (1997) in finding the Atlanto-East Pacific genus Squilla (as restricted by Manning, 1968) to be polyphyletic, and identified further polyphyly in the genus Oratosquilla Manning, 1968. Among these, two species that have often been mentioned in literature but which are poorly documented taxonomically were found not to be closely related to the respective type species of their assigned genera: Squilla parva Bigelow, 1891 (eastern Pacific) was found to lie outside the primary Squilla group (that including the type species, Squilla mantis Linnaeus, 1758), and Oratosquilla kempi (Schmitt, 1931) (western Pacific) was found to be distantly removed from other species of Oratosquilla. Although both Squilla and Oratosquilla are subject to further ongoing study, we herein redescribe S. parva and O. kempi based on type and other material, and propose two new genera for their reception, increasing the number of squillid genera to 49. Material and Methods Morphological terminology and size descriptors follow Ahyong (2001; 2012). Total length (TL) is measured along the dorsal midline from the tip of the rostral plate to the apices of the submedian teeth of the telson. Carapace length (CL) is measured along the dorsal midline and excludes the rostral plate. The corneal index (CI) is given as 100CL/cornea width. Specimens are deposited in the Australian Museum, Sydney (AM); the Florida Museum of Natural History, Gainesville (FLMNH); the National Museum of Natural History, Smithsonian Institution, Washington D.C. (USNM); and the National Taiwan Ocean University, Keelung (NTOU).


Material and Methods
Morphological terminology and size descriptors follow Ahyong (2001;2012). Total length (TL) is measured along the dorsal midline from the tip of the rostral plate to the apices of the submedian teeth of the telson. Carapace length (CL) is measured along the dorsal midline and excludes the rostral plate. The corneal index (CI) is given as 100CL/cornea width. Diagnosis. Dorsal integument finely pitted. Eye large, cornea bilobed. Ophthalmic somite anterior margin emarginate. Ocular scales separate. Carapace with anterolateral spines; median, intermediate, lateral, marginal and reflected marginal carinae present; median carina lacking branches of anterior bifurcation; lower posterolateral margin without obtuse angle. Mandibular palp absent or 1-3 articulate. Maxillipeds 1-5 each with epipod. Raptorial claw dactylus with 6 teeth; carpus with undivided dorsal carina; propodus unarmed distally; merus lacking outer inferodistal spine. Thoracic somite 5 lateral process a blunt diagonal projection, with small ventral spine. Thoracic somites 6-7 lateral processes triangular, faintly bilobed; anterior lobe considerably smaller than posterior lobe. Hook process of petasma apically blunt, longer than tube process. Abdominal somites 1-5 with distinct submedian, intermediate, lateral and marginal carinae; somite 6 with submedian, intermediate and lateral carinae. Telson with prelateral lobe; mid-dorsal surface with curved rows of pits; submedian teeth with fixed apices; postanal carina absent. Uropodal protopod with one lobe between terminal spines; inner margin crenulate.
Etymology. Derived from the combination of the Greek for Michael (Mιχάλης) and the generic name Squilla, in honour of the late Michael Türkay for his career long contributions to carcinology. Gender feminine.
Remarks. Ahyong (2005) showed S. parva to lie outside of Squilla sensu stricto, being probably more New mantis shrimp genera Nauplius, 25: 2017012 closely related to Gibbesia Manning and Heard, 1997. The presence of six rather than five teeth on the dactylus of the raptorial claw, the short and blunt rather than strongly produced lateral process of thoracic somite 5, and the blunt rather than spinular apex of the hook process of the male petasma, however, exclude S. parva from Gibbesia, justifying its removal to the new genus Michalisquilla. Michalisquilla parva n. comb. shares with species of Squilla a distinctly bilobed cornea, a unilobate lateral process of thoracic somite 5 and fixed submedian teeth on the telson. Michalisquilla, however, differs from Squilla as now restricted, in having the posterior lobe of the lateral process of thoracic somite 5 produced to a short, diagonal projection instead of a prominent lateral or anterolaterally produced spine, and a rounded instead of angular posterolateral margin of the carapace. Additionally, the hook process of the petasma is blunt in Michalisquilla instead of being produced to an apical spine, and the hook process of the petasma is markedly longer than, instead of about as long the tube process. Furthermore, Michalisquilla is the only squilloid in the Atlanto-East Pacific with variable segmentation of the mandibular palp, which may be absent or composed of 1-3 articles in adults. All species of Squilla, as well as all other Atlantic squilloids bear an apical spine on the hook process of the petasma, and lack variation in the condition of the mandibular palp. Crenatosquilla oculinova (Glassell, 1942) is the only other eastern Pacific squillid with an apically blunt process on the petasma, but it differs in numerous diagnostic features and is phylogenetically distant, as a member of the Meiosquilla Group, rather than Squilla Group (Ahyong, 2005).
Although further revision of Squilla is required, the removal of S. parva to Michalisquilla renders Squilla homogeneous for the major diagnostic features of a distally pointed hook process of the endopod of male pleopod 1, presence of a 3-articulate mandibular palp, and the lateral process of thoracic somite 5 as a single prominent anterolaterally produced spine.

New mantis shrimp genera
Nauplius, 25: 2017012 Rostral plate linguiform, as wide as or slightly longer than wide; lateral margins weakly carinate; apex rounded; dorsal surface with median carina anteriorly. Carapace anterior width 0.45-0.52CL; anterolateral spines extending slightly beyond base of rostral plate; anterior bifurcation of median carina absent; posterior median projection obtuse.
Telson slightly wider than long; apices of intermediate teeth extending posteriorly beyond base of submedian teeth; prelateral lobe as long as or slightly longer than margin of lateral tooth. Submedian, intermediate and lateral primary teeth each with smooth carina, that of lateral tooth not reaching anteriorly to distal end of prelateral lobe. Submedian denticles rounded; intermediate and lateral denticles blunt, triangular, each with low dorsal tubercle or swelling, often fusing in adult males; denticle formula: submedian 2-4, intermediate 6-8, lateral 1. Median carina interrupted proximally, with slender posterior spine. Dorsolateral surface with rows of shallow pits; supplementary longitudinal carinae absent. Telson postanal carina absent; ventrolateral carina extending almost to base of lateral tooth.
Uropodal protopod terminating in 2 slender spines; lobe on outer margin of inner spine narrower than to slightly wider than adjacent spine, proximal margin concave; inner margin of inner spine crenulate; minute blunt projection proximal to endopodal articulation.
Uropodal exopod proximal article with 9 or 10 movable spines on outer margin, distalmost reaching to midlength of distal article; distal margin with 2 ventral spines, outer spine longer. Exopod distal article as long as or shorter than proximal article.
Colour in life. Translucent with brown speckling and mottling. Carinae and grooves of carapace, body and telson dark-brown; lateral surfaces of thorax and abdomen pale pinkish. Telson with median carina and carinae of prelateral lobe primary teeth dark brown, those of submedian teeth also with dark red hue; anterior one-third of median carina with dark red hue and pair of small, clear spots; general surface pale brown, rows of dorsal pits dark brown. Uropodal protopod with ridges dull-yellow and brown-speckled; endopod with brown distal margins; exopod midrib and distal one-third black, extending onto mesial threefourths of distal article, remainder of distal exopod article yellow. Antennules dark-brown with yellowish peduncular articulations. Raptorial claw white overall; merus with dark brown speckling dorsally, pale yellowgreen meral depression. Pereopods 1-3 translucent, with sparse white and brown speckling.
Remarks. Michalisquilla parva comb. nov. is unusual among squillids in the variably segmented mandibular palp. Palp segments in M. parva are usually minute and relatively undifferentiated, but this is partially related to maturity. Individuals do not exceed TL 80 mm and appear mature at TL 38-44 mm. In juveniles, the palp may be present as a bud, as two minute articles, absent (with an insertion usually present as in the lectotype), or a combination of these states. In adults, New mantis shrimp genera Nauplius, 25: 2017012 the palp is typically 2-or 3-articulate, though in the largest male examined, the palp is absent on one side (with an insertion) and unisegmental on the other; it is not clear if the missing palp was damaged or never present. In other respects, morphological variation is typical of other squillids: eye size and abdominal spination vary allometrically, with eyes proportionally larger in smaller specimens, and the marginal carinae of abdominal somites 1 or 1-2 unarmed in juveniles and small individuals up to TL 39 mm, armed in all others.
The syntype series of M. parva consists of seven specimens (one female and six males). The largest and most intact specimen (an immature male, TL 42 mm, USNM 18479) is herein selected as the lectotype to fix the identity of the species. The remaining syntypes become paralectotypes.
Distribution. Tropical eastern Pacific from the Gulf of California, Mexico, to Peru; intertidal to 132 m, but usually 10-25 m (this study; Hendrickx and Vázquez-Cureño, 1998 Etymology. Named for Harry Vos, "opa" of the first author, for encouragement with her studies. The name is a combination of Vos and the generic name Squilla. Gender feminine.
Remarks. Ahyong (2005) showed by phylogenetic analysis that O. kempi and the type species of Oratosquilla, Oratosquilla oratoria (De Haan, 1844), were not closely related. Oratosquilla kempi was instead sister to a large clade of genera of the Oratosquilla group that included Oratosquilla sensu stricto deeply nested within. Moreover, apart from the similarly uninterrupted anterior bifurcation of the median carina of the carapace, O. kempi differs from other species of Oratosquilla in important diagnostic features. Given the distant phylogenetic position of O. kempi and its aberrant morphology in comparison to other species assigned to Oratosquilla, a new genus is justified, herein named Vossquilla.
Vossquilla shares with Oratosquilla the uninterrupted anterior bifurcation of the median carina of the carapace, but differs in lacking an outer inferodistal spine on the merus of the raptorial claw, in having an irregular instead or distinctly tuberculate dorsal carina on the carpus of the raptorial claw, in having an undivided instead of distinctly bilobed lateral process of thoracic somite 7, and in having dark dorsal pigment patches on abdominal somites 2 and 5. Removal of Vossquilla kempi from Oratosquilla enables consistent diagnosis of the latter genus. Oratosquilla can now be clearly diagnosed by the combination of an uninterrupted anterior bifurcation of the median carina of the carapace that opens anterior to the dorsal pit, a tuberculate dorsal carina on the carpus and presence of an outer inferodistal spine on the merus of the raptorial claw, and the bilobed lateral processes of the thoracic somites 5-7.
Rostral plate subtrapezoid, slightly wider than long; lateral margins carinate; apex truncate to rounded; dorsal surface smooth or with short median tubercle or carina. Carapace anterior width 0.47-0.51CL; anterolateral spines not extending beyond base of rostral plate; anterior bifurcation of median carina well-defined, about as long as distance between base of bifurcation and dorsal pit; posterior median projection obtuse.

New mantis shrimp genera
Nauplius, 25: 2017012 Telson about as long as wide to slightly wider than long; apices of intermediate teeth extending posteriorly to base of submedian teeth; prelateral lobe slightly shorter to slightly longer than margin of lateral tooth. Submedian, intermediate and lateral primary teeth each with smooth carina, that of lateral tooth extending anteriorly slightly beyond distal end of prelateral lobe. Marginal denticles rounded, submedian and intermediate denticles each with low dorsal tubercle or swelling; denticle formula: submedian 2-4, intermediate 6-8, lateral 1. Median carina interrupted proximally, with tubercle below posterior spine. Dorsolateral surface with rows of shallow pits; supplementary longitudinal carinae absent. Telson ventral surface with short postanal carina, extending posteriorly to about proximal one-fourth of distance to between anal pore and posterior margin; ventrolateral carina extending almost to base of lateral tooth.
Uropodal protopod terminating in 2 slender spines; lobe on outer margin of inner spine narrower than adjacent spine, proximal margin concave; inner margin of inner spine crenulate; minute tooth proximal to endopodal articulation.
Uropodal exopod proximal article with 7 or 8 movable spines on outer margin, distalmost spine reaching to proximal one-third of distal article; distal margin with 2 ventral spines, outer longer. Exopod distal article slightly longer than proximal article.

Colour in life.
Light grey-brown dorsally, darker middorsally. Carinae and grooves of carapace, submedian carinae, intermediate carinae, and abdominal somite 6 lateral carinae dark red. Mid-posterior margin of carapace yellow orange. Abdominal somite 2 and 5 with transverse black-brown patch between intermediate carinae, that of somite 5 on posterior half. Telson with median carina and prelateral lobe dark red; primary teeth with white tips and dark green carinae; telson surface with dark, irregular grey-green band across central one-third; submedian denticles white; intermediate and lateral denticles dull yellow-green. Uropodal protopod with whitish base colouration and dark yellow-green carinae, terminal spines white; endopod with speckled yellow distal half; exopod with white movable spines, with deep blue patch on distal half of proximal article; exopod distal segment diffuse blue in mesial half, diffuse white-yellow on lateral half. Antennules with black speckling. Raptorial claw white overall; merus with black and pink speckling dorsally, yellow-green meral depression and pale orange ventral outer margin; carpus white with yellow spot proximally; propodus with yellow disto-extensor margin and diffuse brown speckling; dactylus white. Pereopods 1-3 translucent white, yellowish distally.
Remarks. The series of V. kempi examined is largely consistent, with variation in abdominal spination that is largely size related. The intermediate carinae on abdominal somite 4 are unarmed in the smallest specimens (male TL 28, female TL 30 mm, NTOU), armed in all others. The prelateral lobes range from slightly shorter to slightly longer than the margins of the lateral teeth and the rostral plate may have a short median carina or dorsal tubercle, but is usually smooth dorsally; these variations appear unrelated to body size.
The dorsal carina of the raptorial claw carpus in V. kempi has been characterized as irregularly tuberculate as in O. oratoria (e.g., Manning, 1971;1995), though the condition in V. kempi is better characterized as smooth or irregular, but not distinctly tuberculate; the condition varies allometrically, being smooth in the smallest specimens, becoming increasingly irregular with increasing body size. In Oratosquilla, the dorsal carina of the carpus of the raptorial claw is distinctly, albeit irregularly tuberculate in adults, and less pronounced in juveniles.
Distribution. Vietnam, China, Japan and for the first time from Taiwanese waters (Kinmen); intertidal to shallow subtidal depths.